Mysticeti
Eubalaena glacialis Muller 1776 Right whale
The range of this species used to include all temperate waters of the North Atlantic, North Pacific, and southern hemisphere (Rice and Scheffer, 1968). Tomilin (1967) gives a more detailed account of its distribution, as do the whaling maps of Townsend (1935). The distribution of stocks is discussed in detail by the Report of the (1983) Workshop on the Status of Right Whales (IWC/35/Rep2). Berzin and Vladimirov (1981) state that the population in the North Pacific used to number around 10 000 before exploitation, but that currently only around 200-500 remain. The Report of the Status of the Right Whale Workshop lists other estimates of population sizes and numbers of whales sighted in a number of areas worldwide, indicating a total world population of at least 2 000. The report also summarises information on feeding habits of this species. Tomilin (1967) states that the main food in the North Atlantic is the calanoid copepod C. finmarchius, and the schizopod Thysanoessa inermis. Omura et al (1969) also report that the main food is calanoid copepods in the North Pacific. Tomilin states that no fish have ever been found in stomachs of this species, and adds that the right whale is now extremely rare. A few animals are known to become entangled in fishing gear. (See areas 21, 57 and 41).
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Balaena mysticetus Linnaeus 1758 Bowhead whale
Confined to Arctic waters, or floating ice areas (Tomilin 1967). There are 4 or 5 stocks in the Arctic waters, all of which have been decimated by commercial whaling over 4 centuries. Braham (1982) estimates the current population size to be around 5 000 in all, which is around 5–10% of the original population size. Some stocks are more depleted than others, the Spitzbergen stock possibly being extinct (see area 27). Townsend (1935) provides a map of the original distribution of this species in the North Pacific area, as represented by whaling catches. Calanus finmarchius is the main food in the North Atlantic (Tomilin 1967), and pelagic copepods and euphausids form most of the diet in the Bering Sea area (Marquette et al 1982). Tomilin states that fish are not eaten, and no interactions with fisheries have been recorded.
18 21 27 61 67
Caperea marginata (Gray 1846) Pygmy right whale
Ross et al (1975) describe the distribution of this species, based on 71 recorded individuals at that time, as circumpolar in the southern hemisphere, north of the Antarctic convergence, and south of about 31°S. They suggest the northern distribution may be limited by the 20 degree isotherm. Citing Ivashin et al (1972), Ross et al state that Caperea feeds mainly on copepods and that as such its distribution patterns probably follow those of sei and right whales in the southern hemisphere. This species has occasionally been caught accidentally in beach seines in South Africa (see area 47). No population estimates are possible, but it cannot be considered common, even though it has never been exploited.
41 47 51 57 81 (87)
Eschrichtius robustus (Lilljeborg, 1861) Grey whale
Hershkovitz (1966) describes the distribution of this species as extending from around 72°N in the Oriental Arctic, southwards to Mexico in the east and to Japan and Korea in the west. Of the 2 stocks, the eastern Pacific stock has recovered from a few thousand at most in the 1880's to 1930's, to an estimated 11 000 today, from an initial population of about 15 000 (see area 77). The western stock is near extinction (see area 61), and a 3rd stock, in the Atlantic went extinct some centuries ago (Hershkovitz 1966). Zimusko & Ivashin (1980) state that although they have identified 70 different food species, the main food is amphipods. Little interaction with fisheries is known. Wolman & Rice (1979) suggest that increased boat traffic in the breeding lagoons in Mexico, some of which is fishing boats, may jeopardise breeding. A few whales are known to get entangled in gill nets in California (see area 77)
18 61 67 77
Balaenoptera physalus (Linnaeus, 1758) Fin whale
According to Tomilin (1967) this species is found in all oceans, and is particularly abundant in the Antarctic “in warm weather”. It is not so abundant in the northern hemisphere, but is still the dominant species of baleen whale there. It is more common in the North Pacific than the North Atlantic, and rare in the tropics, rarer than the blue whale. Tomilin gives a detailed description of the distribution.
Gambell (1976) gives estimates for the original population sizes of the various stocks before whaling. The initial world total population size may have been around 700 000. The North Atlantic population of fin whales has been divided into 7 non interbreeding management stocks by the IWC (see Rorvik & Jonsgaard 1981). The latest figures for stock sizes in these areas total 11 550 (IWC 1984: Report of the Sub-Committee on Other Baleen Whales; IWC 1977: Report of the Sub-Committee on North Atlantic Whales). Using Gambell's (1976) conversion figure of total population being 1.5 times the exploitable stock size, the total population of the North Atlantic may exceed 17 000. In a similar manner the IWC has estimated the stock sizes for the southern hemisphere at around 82 000 (IWC 1979: Report of the Sub-Committee on Protected Stocks; IWC 1981: Report of the Sub-Committee on Other Baleen Whales), which would suggest a total population of around 122 000. There are no recent IWC estimates for North Pacific stocks, but these are presumably nearer to the size of the Atlantic population than the southern hemisphere. (Gambell (1976) gives a figure of 24 000.) A world total population therefore might not exceed 163 000 animals.
Tomilin (1967) gives detailed accounts of feeding around the world which includes a number of small pelagic schooling fish species, such as herring, smelt, capelin, arctic cod and sand eels, as well as some larger fish such as cod and salmon, and a number of pelagic crustacea. The diet is much more varied in the northern hemisphere than the southern, as this species shares the feeding, and breeding, habits of other baleen whales in the Antarctic, feeding on krill (largely Euphausia superba) in the summer and fasting in more northerly latitudes in the winter. There has been some reported interaction with fisheries, although all such instances have been of an operational nature (see areas 21 and 37).
18 21 27 31 34 37 41 47 48 51 57 58 61 67 71 77 81 87 88
Balaenoptera musculus (Linnaeus, 1785) Blue whale
Another cosmopolitan species which according to Tomilin (1967) prefers colder waters and shuns coastal zones. He states that large numbers are found in selected areas, around South Africa, South America, and Australia in the austral winter, and that there are “incomparably fewer” in the northern hemisphere. In the south, the usual baleen whale habits are observed as regards feeding and breeding. In the northern hemisphere the food is, again according to Tomilin, macroplankton, especially Thysanoessa inermis, and not fish. Nemoto (1959) states that blue whales prefer euphausiids in the North Pacific. The northern stocks winter in subtropical belts. It is worth noting that Ichihara (1966) first noted the presence of smaller blue whales, which he called B. brevicauda, in the summer north of the Antarctic convergence in the Indian Ocean. Other people have also noted the presence of blue whales in the subtropical and even tropical belt in summer. Berzin (1978) saw a considerable number in the eastern tropical Pacific in June, and Tomilin states that not all whales migrate to the poles in summer.
Gambell (1976) suggests that the initial population throughout the world may have totalled around 250 000, and that at present it numbers around 10 000, three quarters of which are in the southern hemisphere. Gulland (1981) suggests that the total population in the southern hemisphere is around 10 000, whilst Grenfell (1981) puts the figure for the total population of Antarctic areas II, III, and IV at over 20 000. Clearly there is no satisfactory world population estimate, but this cannot be more than a few tens of thousands. There have been no records of interaction between this species and fisheries anywhere, as yet.
18 21 27 31 34 41 47 48 51 57 58 61 67 71 77 81 87 88
Balaenoptera acutorostrata Lacepede, 1804 Minke whale
Minke whales occur from the edge of the ice in both Arctic and Antarctic seas to the tropics, but according to Tomilin (1967), are rare in the tropical areas. In the southern hemisphere they exhibit the usual baleen whale characteristics of feeding on krill and migrating to fairly well defined breeding sites in the winter. In the northern hemisphere they are perhaps, again according to Tomilin, the most icthyophagous of baleen whales, feeding on a wide range of schooling fish, especially herring and capelin, but also cod, whiting and pollack.
The latest Report of the Sub-committee on Minke Whales (IWC 1984) suggests that a reasonable figure for the total population of minke whales in the southern hemisphere might be around 580 000. Only two other stock sizes have been estimated, that of the exploited Barents Sea population may total 60 – 90 000 animals, and that of the Korean stock as much as 14 000 (IWC 1984) animals in all. There are no estimates of a world population size, but if, as is the case for other baleen whales, the southern hemisphere stocks are larger than the northern hemisphere ones, then there are unlikely to be more than 1 million animals in all. Minke whales, being small, have not until recently been the subject of much commercial exploitation, although since 1975 catches have been in the region of 5 – 10 thousand per year worldwide (Brown 1982). Minke whales are known to become trapped in Canadian and other fishing nets (see areas 21, 37 and 61) and have also drawn comment in Norway for their icthyophagous habits (see area 27).
18 21 27 31 34 37 41 47 48 51 57 58 61 67 71 77 81 87 88
Balaenoptera borealis Lesson, 1828 Sei whale
Occurring in all oceans of the world up to the ice, but Tomilin (1967) states that it is more warmth loving than physalus, and is rare south of the Antarctic convergence or north of Japan or east of the North Cape in Norway. Tomilin also states that sei whales do not migrate as regularly as other baleen whales and are often found in shallow waters. The diet consists of both pelagic crustacea and small schooling fish, although Kawamura (1974) states that in the southern oceans borealis feeds almost exclusively on copepods and euphausiids. Nemoto (1959) also states that they prefer copepods in the North Pacific, agreeing with Tomilin, who asserts that they are less well adapted to eating fish than are fin or humpback whales. The world population was estimated by Gambell (1976) to have been around 300 000 prior to exploitation, and to be around 110 000 at present. The Report of the Special Meeting on Sei Whales (IWC 1980) however, suggests that there are only 15 – 30 000 sei whales in the southern hemisphere, so that 110 000 may be considered optimistic for the world population. There have been no reported interactions between this species and any fisheries as yet.
21 27 31 34 41 47 48 51 57 58 61 67 71 77 81 87 88
Balaenoptera edeni Anderson, 1878 Bryde's whale
Ivashin (1980) gives a comprehensive account of the distribution of this whale, which although centred on the tropics extends as far north as 43°N in the Pacific, and around 37°S in the south. The distribution of this species may be limited by the 15° isotherm (NOC 1980). There is apparently not enough information as yet to distinguish separate stocks, nor to make any reliable population estimates. The fact that the catch statistics of this species used to be included in the statistics for sei whales also makes an assessment of the status of this species very difficult (NOC 1980). Nemoto (1959) lists anchovies, Yarrella sp., Myctophum sp., and horse mackerel, as well as euphausiids as food items in the diet of this species in North Pacific waters. Omura (1966) also states that both small fish and euphausiids are eaten in the North Pacific. As yet there are no reports of interaction with fisheries although this whale is known to feed on the same stocks of small fish as are fished for commercially (see e.g. Best 1967).
21 31 34 41 47 51 57 61 71 77 81 87
Megaptera novaeangliae (Borowski, 1781) Humpback whale
Humpbacks are found in all oceans, performing long migrations from feeding grounds in colder waters to breeding grounds in warmer ones. Tomilin (1967) states that at least 10 such migration routes are known, one on each side of the North Pacific and Atlantic, whilst humpbacks feeding in Antarctic waters migrate to the coasts of Zaire, Madagascar, Peru, Australia, New Zealand and Tonga to breed. Townsend's (1935) maps of whale distribution clearly show concentrations around each of these areas, two such occurring off Australia. In Antarctica humpbacks feed on krill inside the Antarctic convergence, whilst in the northern hemisphere, feeding occurs as far north as the Chukchee Sea, and Svalbard, the diet here consisting of a number of small fish species, notably Capelin (Mallotus villosus), and other fish of the families Clupeidae, Osmeridae, Gadidae, Salmonidae, Ammodytidae, and Hexagrammidae, as well as pelagic crustacea (Tomilin 1967). Chittleborough (1965) refers to some limited feeding during migration of southern stocks, on pelagic decapod crustacea, but he thought this was of minor importance.
There do not appear to be reliable estimates for all of the stocks, but Berzin and Vladimirov (1981) suggest that the North Pacific stocks number about 1 500, or maybe a tenth of their initial population size. There are estimates of the North West Atlantic stock ranging from less than 1 000 to more than 4 000 (see area 21), but this stock was probably never as large as the Pacific ones, and may be fully recovered now (NCC 1980). The Eastern Atlantic population size is unknown, but a few hundred individuals have been sighted (Annex G, IWC 1983). Gambell (1976) suggests that the total population in the southern oceans may be only around 3 000, from an initial stock size of around 100 000.
Humpbacks have been implicated in a few interactions with fisheries in the northern hemisphere. There have been a number of entanglements in fishing nets in Canada, and there has been a suggestion that the over-exploitation of the capelin stocks there have also led to a reduced recruitment to the humpback population (see area 21). In area 61 there have also been reports of whales annoying salmon fishermen (Tomilin 1967).
18 21 27 31 34 41 47 48 51 57 58 61 67 71 77 81 87 88
Odontoceti
Tasmacetus shepherdi Oliver 1937 Shepherd's Beaked whale
Like most of the beaked whales this species has only rarely been recorded. Mitchell (1975) states that it was known from only about 8 specimens, all from New Zealand and South America. Obviously population estimates are impossible on the basis of such limited information. Mead and Payne (1975) have suggested that the diet may consist of deep water bottom dwelling organisms, on the basis of the stomach contents of their specimen from Argentina, which consisted of the hake Merluccius hubbsi, a serranid, brotulid remains, which formed the bulk of the food, as well as some crab and squid remains. There have been no recorded operational interactions with fisheries yet, and the implications of the fact that commercial fish species are included in the diet remain obscure at present.
41 81 87
Berardius arnuxii Duvernoy, 1861 Arnoux's Beaked whale
Mitchell (1975) states that this species has been recorded from New Zealand, South Australia, the Falkland Islands, Argentina, South Africa, South Georgia, South Shetlands and the Antarctic Peninsula. Again this indicates a southern circumpolar distribution of a population of unknown size. McCann (1975) also states that this species is not found north of about 30°S, and that it feeds on cephalopods. No interactions with fisheries are known anywhere.
41 47 48 51 57 58 81 87 88
Berardius bairdii Stejneger, 1883 Baird's beaked whale
Confined to the North Pacific, in offshore waters from the Pribilof Islands and Alaska to southern California on the one side, and from the Sea of Okhotsk to southeast Japan on the other (Mitchell 1975). The diet consists mainly of squid, Gonatus fabricii and Onychoteuthis sp. having been found in the stomachs of North East Pacific specimens (Rice 1963). There is a small fishery in Japan, much reduced in recent years from a few hundred in the 1950's (Mitchell 1975) to around 30 in 1981 (IWC 1982 p 125). According to Ohsumi (1975) there has been no decrease in the catch per unit effort however, so the stocks are presumed not to be depleted. There are no records of interactions with fisheries.
61 67 77
Mesoplodon spp.
12 species have been recognised in this genus (Moore 1966), yet almost all of these remain virtually unknown. Most seem to feed on squid, as attested to by the characteristic reduction in dentition (Gaskin 1976), though Mitchell (1975) thought that a variety of fish may also be taken. In general they are associated with deep water, and occur in small groups (Mitchell 1975). Moore (1966) has suggested that the distribution of those species recorded around American waters at least, approaches allopatry. This is not so clear for a number of other species, however, where distribution at present seems to be largely conjectural. Almost all of them should be regarded as rare on the basis of the number of animals seen, though their apparent shyness of boats and often remote habitat may lend some bias to this suggestion; no population estimates are possible for any of the species (NCC 1980). Interactions with fisheries are almost unknown (but see below: M. ginkgodens), and are at any rate unlikely to be significant in any species due to their squid - eating habits and apparent scarcity.
Mesoplodon pacificus (Longman, 1926) Longman's beaked whale
Only two individuals have ever been definitely identified, one in Australia, the other in Somalia (Azzaroli, 1968), but Keller et al (1982) report that they saw beaked whales which may have been of this species near the Seychelles. If the distribution of this species is continuous then its range should extend over the Indian Ocean and Indo-Pacific region.
51 (57) 71
Mesoplodon bidens (Sowerby, 1804) Sowerby's beaked whale
According to Moore (1966) this species is inferred to inhabit the North Sea and adjacent waters, straggling to the North American coast.
21 27 37
Mesoplodon densirostris (de Blainville, 1817) Blainville's beaked whale
Otherwise known as the dense-beaked whale, this is possibly the most widely distributed of all Mesoplodon species. It has been reported from tropical and warm temperate waters of the Indian Ocean, the South Pacific, the southern North Atlantic, and the North Pacific (NOC 1980).
21 31 34 (41) 47 51 (57) 61 71 77 81
Mesoplodon europaeus (Gervais, 1855) Gervais' beaked whale
Moore (1966) suggests that this species is centred on the Antillean region, straggling northwards to New York and to England on the Gulf stream. Rankin (1953) reported that at that time there were only 6 records of this species.
21 27 31
Mesoplodon layardii (Gray, 1865) Strap-toothed whale
Hershkovitz (1966) records this species from Australia, New Zealand, and the mid south Atlantic. Leatherwood and Reeves (1983) add South Africa, Uruguay, the Falkland Islands and Tierra del Fuego. They suggest a distribution outside Antarctic waters with a northern limit of about 30°S.
41 47 51 57 71 81
Mesoplodon hectori (Gray, 1871) Hector's beaked whale
Leatherwood and Reeves (1983) suggest a temperate southern hemisphere distribution extended to the temperate eastern North Pacific, specimens having been found in Tierra del Fuego, New Zealand, Tasmania, South Africa, the Falklands Island and California.
41 47 57 77 81
Mesoplodon grayi von Haast, 1876 Gray's beaked whale
At first sight, another species with a circumpolar southern hemisphere temperate distribution (NCC, 1980). Watson (1981), however, cities Boschma's (1950) record of a stranding in Holland. The distribution of this species therefore remains unclear.
27 41 47 51 (57) 81 87
Mesoplodon stejnegeri True, 1885 Stejneger's beaked whale
Hershkovitz (1966) gives this species a North Pacific distribution, from Akita beach in Honshu, Japan, to the Bering Sea and to the Oregon coast of North America. Moore (1966) considered that its main area of distribution was the sub-arctic North Pacific, with stragglers occuring further south. Leatherwood and Reeves (1983) states that strandings are fairly common in the Aleutians, suggesting the species may be most numerous in that area.
61 67
Mesoplodon bowdoini Andrews, 1908 Andrew's beaked whale
According to Leatherwood and Reeves (1983) this species has so far been recorded only from strandings in New Zealand, Tasmania, Western and Eastern Australia, and Kerguelen Island but Nishiwaki (1962) also records a specimen from Akita beach in Honshu, Japan. If distribution is continuous, then this species should also occur in area 71.
57 61 (71) 81
Mesoplodon mirus True, 1913 True's beaked whale
Moore (1966) considers that this species may inhabit primarily deep water of the continental shelf off the mid-Atlantic States of the USA, straggling north wards to Europe. A number of specimens have also been recorded from Sout Africa (IWC 1980), once again making the distribution of this species somewhat conjectural.
21 27 31 47
Mesoplodon ginkgodens Nishiwaki & Kamiya, 1958 Ginkgo-toothed beaked whale
This species has been found in Japan, Taiwan, California and Sri Lanka (Leatherwood and Reeves 1983). Watson (1981) refers to “at least 2” further, unconfirmed, records of animals being taken on Japanese longliness near Taiwan, which might indicate a diet of fish as well as the presumed diet of squid, though longliness are often baited with squid. Leatherwood and Reeves (1983) suggests that on the basis of the location of strandings to date, this species is the most common in the Western North Pacific.
51 (57) 61 (71) 77
Mesoplodon carlhubbsi Moore, 1963 Hubb's beaked whale
Moore (1966) states that this species is found in the North Pacific temperate waters, generally to the south of the area inhabited by M. Stejnegeri. Leatherwood and Reeves (1983) suggest it may be limited to the waters around Honshu in the Western Pacific, and from Vancouver to San Diego in the east.
61 67 77
Ziphius cavirostris G. Cuvier, 1823 Cuvier's beaked whale
Apparently found in all Seas, but rarely polar ones (NCC 1980), there are numerous reports of strandings of this species from all over the world, which indicates that it may be relatively common. Tomilin (1967) however states that whereas it is found in all oceans it is not numerous in any; Tomilin also states that like all squid eating beaked whales, this is a pelagic species. Erdman's (1962) specimen from Puerto Rico contained only squid in its stomach, but Mitchell (1975) states that in some areas deep water fish may predominate. It has been subject to some small scale hunting in mixed small whale fisheries in Japan and St Vincent (Mitchell 1975a) but has not, it would appear, been involved in any interaction with fisheries anywhere.
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Hyperoodon ampullatus (Forster 1770) Northern bottlenose whale
Found throughout the North Atlantic, from the Artic Ocean, Spitzbergen and Greenland (Mitchell 1977) to Rhode Island, Cape Verde and the Mediterranean (Tomilin, 1967). Benjaminsen (1972) states that it avoids shallow waters, preferring those mostly greater than 1 000m in depth, or according to Mitchell (1977) submarine canyons. Food is principally cephalopods, chiefly Onycoteuthis, Loligo and Sepia spp. according to Tomilin, or Gonatus fabricii according to Benjaminsen. Tomilin also states that either by accident or in supplement, some fish are also taken, such as herring and cod, and also starfish and holothurians. Mitchell (1977) maintains that the population is currently depleted after centuries of hunting, notably by the Scots and Norwegians. There are no records of direct interaction with fisheries however.
21 27 37
Hyperoodon planifrons Flower, 1882 Southern bottlenose whale
A circumpolar southern hemisphere species, reported from South America, South Africa, Australia, New Zealand and the Indian and Pacific Ocean coasts of Antarctica (NCC 1980). Mitchell (1975) states that it is widespread throughout the range, and cities Hale (1931) that the stomach of one specimen was full of squid remains. He also states that this species is occasionally taken by whalers in the Antarctic waters. There are no interactions with fisheries at present, nor would any seem likely.
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Physeter macrocephalus Linnaeus, 1758 Sperm whale
Found in all seas, chiefly between 40°S and 40°N. Females are found in subtropical zones, whereas males may be found as far as the polar ice fields (Tomilin, 1967). Townsend's (1935) maps also show the distribution of sperm whales throughout the year. Tomilin states that the distribution of sperm whales is limited by the distribution of cephalopods, on which they feed, and which tend to prefer warmer, more salty waters. Numerous presumed feeding grounds are evident in Townsend's maps, notably along the equator in the Pacific basin (“On The Line”), off Angola (“Carroll Ground”), and in the central North Atlantic (Charleston, Western, and Twelve Forty Grounds). Sperm whales have been hunted for centuries, and at present continue to be in the Pacific.
There are no accurate assessments of population sizes, but Gambell (1976) thought that the male populations in the southern hemisphere and the North Pacific were about half of the initial population size, and the female stocks in both areas were reduced by about a third. By his estimates the total population of males and females in both of these areas is a little more than one million animals. He also estimates the total population in the Atlantic as currently around 22 000. Some later individual stock assessments are given in the area accounts.
Sperm whale diet has been studied in a number of regions throughout the world, notably in the North Pacific. Clarke (1980) and Berzin (1972) both give useful summaries of information on sperm whale diets. Berzin states that 25 species of squid have been identified in sperm whale stomachs, the most important being squids of the families Gonatidae, Onychoteuthidae, Histioteuthidae and Ommastrephidae. Berzin also states that Betesheva found more than 24 species of fish in sperm whale stomachs; between 12% and 30% of stomachs of whales from the northwestern Pacific had some fish in them over a number of years. Mizue (1951), however found fish in only 3.4% of stomachs which he analysed. The most important fish species found were from the families Macruridae, Gadidae, Cottidae, Scorpaenidae as well as sharks and rays. There appears to be only one reported instance of any interaction between sperm whales and fisheries (see area 37). The only significant area of overlap in prey species occurs with the squid species Todarodes pacificus, which is both eaten by sperm whales and fished for around Japan.
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Kogia breviceps (de Blainville, 1838) Pygmy sperm whale
Distributed mainly in “tropical and warm waters” (Mitchell, 1975). Tomilin (1967) states that it occurs as far as Holland, Nova Scotia, Japan, Southern California, and the Kuril Islands in the northern hemisphere, and as far as the Cape of Good Hope, Tasmania, and Chile in the southern hemisphere. Records from South America and Africa are scarce (Handley, 1966), but this may be due to the fact that they are not noticed so much in such areas. There are no estimates of population size, but Mitchell (1975) suggests that their apparent rarity may be due to earlier unrecorded exploitation by whaling ships as practice targets, though this view has been criticised (NCC 1980). Currently they are taken in small numbers in Japan, and possibly in Indonesia (Mitchell 1975). Handley (1966) states that they feed on squids, crabs and shrimps, and Fitch and Brownell (1968) add some fish also. The fact that this species feeds mainly on squid, is not particularly common, and travels in small groups of 3 – 6, or alone (Mitchell 1975) might suggest that interactions with fisheries are unlikely, but some gear conflicts have been reported (see area 61).
21 27 31 34 (41) 47 51 57 61 71 77 81 87
Kogia simus Owen, 1866 Dwarf sperm whale
This species was for a long time confused with the previous one (Handley 1966), and so there is little exclusive information pertaining to it (Mitchell 1975). Handley states that it has been found in South Africa, India, Sri Lanka, Japan, Hawaii, South Australia, and eastern USA Leatherwood and Reeves (1983) add California and Guam. Like the previous species it must be considered uncommon and no population estimates are possible. Leatherwood and Reeves (1983) suggest that it may prefer the edge of the continental shelf. Fitch and Brownell (1968) found that deep water fish supplement the main diet of squid. Again, interactions seem to be limited to occasional gear conflicts (see area 61).
31 (34) (41) (47) 51 57 61 (71) 77 (87)
Monodon monoceros Linnaeus, 1758 Narwhal
Tomilin (1967) states that this species is confined to the Arctic Ocean, north of the ‘drifting ice boundary’; Mitchell (1975) adds that it is absent from the north Siberian shelf and rare in the north Alaskan sector. Hershkovitz (1966) reports its presence as far south as the Bering Sea in the Pacific region and the Netherlands in the Atlantic. These must represent extremes however. There are no population estimates for the species as a whole, but Mitchell (1975) records a ‘conservative’ estimate of the northern Canadian and northwestern Greenland stock to be around 10 000. Tomilin states that the species has been severely reduced in the region around Novaya Zemlya and Franz Josef Land. The diet according to Tomilin is made up from squids in the main, but also some fish including skate, flounder, halibut, cod, salmon and herring. Meldagaard and Kapel (1981) found that Boreogadus saida, the Arctic cod, predominated in one stomach they examined, whilst Finley and Gibb (1982) found Boreogadus and several other species including Arctogadus sp., Rheinhardtius hippoglossoides and Gonatus fabricii in their samples. This species is hunted in and around eastern Canada and western Greenland. No direct interaction with fisheries is known at present.
18 21 27 61 67
Delphinapterus leucas (Pallas, 1776) White whale
Tomilin (1967) describes the white whale as widespread in cold waters, adding that it stays in the coastal zone. Gurevich (1980) provides a useful review of this species and gives details of distribution and diet. The southerly limits to distribution are France and New York in the Atlantic, and the Sea of Japan and the Gulf of Alaska in the Pacific. The diet consists largely of fish, and Gurevich provides a comprehensive list of these; they include Arctogadus glacialis, Mallotus villosus, Ammodytes spp. and various other small fish, as well as a variety of flatfish and some more commercially valuable fish, such as salmon and haddock. Gurevich states that no other small whale has such a varied diet, but that they usually feed on small fish, crustaceans and benthic animals such as molluscs and polychaete worms, adding that they may be unable to swallow large fish and that deep water organisms are entirely absent from the diet. Mitchell (1975) lists a possible 9 separate stocks. Sergeant and Brodie (1975) have estimated the North American population as around 30 000 or more individuals. The report of the Sub-Committee on small Cetaceans (IWC 1982) gives figures of 232 and 1 570 as minimum and maximum counts of white whales in the Barents, Kara and white seas. The varied diet of the white whales probably safeguards it from any immediate threat to its food supply, but the fact that its diet includes commercial fish species may not protect it from some criticism at least (see area 27). White whales have been involved in incidental catches and mortalities in fishing operations (see areas 21 and 67), and they have also been hunted over their entire range (Mitchell 1975).
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Steno bredanensis (Lesson, 1828) Rough-toothed dolphin
Hershkovitz (1966) gives the distribution of this species in the Atlantic from the Netherlands and Virginia in the north, to the coast of Argentina and to north east of Tristan da Cunha. In the Pacific it is recorded from California, Japan, and the Galapagos Islands, and in the Indian Ocean from South Africa to Aden and Indonesia. Mitchell (1975) also records its presence in small numbers in the Mediterranean. There are no population estimates, but Leatherwood and Reeves (1983) suggest that they are widely distributed without being known to be numerous in any particular area, and prefer deep waters far offshore. Perrin and Watkin (1975) found fish and molluscs in stomachs of animals from the Pacific, and Layne (1965) recorded pelagic octopus in Florida, otherwise there is little information on feeding. This species has been caught in tuna nets (see area 77) and is sometimes deliberately taken in the St Vincent small whale fishery (see area 31) as well as in Japan both deliberately and incidentally (see area 61). There appears to be no major problem for either the species or fishermen with this degree of interaction however.
21 27 31 34 37 41 47 51 57 61 71 77
Sotalia fluviatilis (Gervais, 1853) Tucuxi
Hershkovitz (1966) recognised 3 separate species, though these are curently considered to be conspecific. The distribution of the three forms is, according to Hershkovitz, throughout the Amazon river and in the lower parts of its tributaries, along the coasts and in the rivers of Venezuala and the Guianas, and along the coast of Brazil, possibly as far as Sao Paulo, but with certainty only in the Baia de Rio de Janeiro. Mitchell (1975a) states that it occurs all along the South American coast from Lake Maracaibo to Santos in Brazil. There are no population estimates of this species. Mitchell (1975a) states that they eat armoured catfish and some crabs and prawns. Leatherwood and Reeves (1983) state that shoaling fish are also eaten in the central Amazon. Mitchell (1975a) and Leatherwood and Reeves (1983) both refer to catches along the coasts of Brazil and Surinam in gill nets around river mouths (see areas 31, 41).
31 41
Sousa chinensis (Osbeck, 1765) Indo-Pacific hump-backed dolphin
This species was previously thought of as 4 separate species (NCC 1980). The distribution is from near the Cape of Good Hope around the East African coast to the Red Sea, through the Indonesian archipelago, to Australia, Sydney on the east and Carnarvon on the west, and up to the Canton River in China (Mitchell 1975). Mitchell also states that data on feeding is lacking, but says that they eat fish. Saayman and Taylor (1973) describe their feeding behaviour as solitary and dispersed, feeding in rocky areas and reefs, often near breaking waves. They have been caught in nets incidentally along the African and Australian coasts (see areas 51 and 57), but elsewhere apparently remain uninvolved with fisheries, perhaps surprising for a coastal species.
47 51 57 61 71
Sousa teuszii (Kukenthal, 1892) Atlantic hump-backed dolphin
Mitchell (1975) states that its presumed range is along the West African coast from Mauritania in the north to Angola in the south and that the only information on the population size is that it is rather common in the coastal waters of Senegal. Busnel (1973) describes the way fishermen in Mauritania use the dolphins feeding behaviour to catch mullet, which the dolphins also eat (see area 34). Cadanet (1956, 1957, 1959) also reports some taken in shark nets. These are the only records of interaction with fisheries.
34 47
Orcaella brevirostris (Gray, 1866) Irrawaddy dolphin
Distributed in coastal waters, estuaries and rivers of the Indian ocean and South China Sea from North Borneo (Sabah) to the Bay of Bengal and up the Mekong, Ganges and Irrawaddy rivers (Mitchell 1975). Also found in northern Australian waters and in Papua New Guinea (Mitchell 1975). There is little data on feeding, beyond Mitchell's (1975) suggestion that the species feeds on fish as well as crustaceans, and no information on the size of the population. There have been a few instances of interaction with fisheries (see areas 57 71).
57 71
Peponocephala electra (Gray, 1846) Melon-headed whale
Distributed throughout tropical seas north of 10°S, but apparently unknown from South American waters, and with few records in the Atlantic. There are no estimates of the population size, but it does not seem to be particularly rare, especially in the Pacific, and may normally be distributed away from land masses (NCC 1980). There is no data on feeding. This species has been caught, infrequently, in tuna nets, (see area 77) and has been caught deliberately and incidentally elsewhere (see area 61 31). This has probably had little effect on the population.
31 34 41 47 51 57 61 71 77
Feresa attenuata Gray, 1875 Pygmy killer whale
Caldwell and Caldwell (1971) chart the records of this species untill 1971. It is recorded, infrequently, from warm waters worldwide: Caribbean, Senegal, South Africa, Japan, and the tropical Pacific. Racey and Nicoll (1982 in press) cited by Keller et al (1982) also record it around the Seychelles, thereby confirming its worldwide distribution. It has been taken in some small whale fisheries, in Japan (Nishiwaki et al 1965), and in St Vincent (Caldwell & Caldwell, 1975). Pryor et al (1965) report that a specimen in captivity in Hawaii ate mackerel, squid, and other fish, as much as 12 lbs per day, whereas Nishiwaki et al (1965) reported that their specimen rejected squid, saurie and mackerel-pike, but accepted sardines. The data on feeding is therefore somewhat confused. There is no information on the population status of this species: the paucity of records may indicate that it is very rare (NCC 1980), yet Pryor et al reported seeing one school of about 50 individuals. They have been taken accidentally in fishing nets (see area 77), but the infrequency of their occurrence makes such conflicts unlikely to affect their population dynamics, unless whole schools are taken.
31 34 47 51 (57) 61 71 77 (87)
Pseudorca crassidens (Owen, 1846) False killer whale
Widely distributed throughout warm and temperate waters, from the North and Baltic Seas and the Davis Straits, to South Africa and Patagonia in the Atlantic; from the Bering Sea to Chatham Island, Tasmania and New Zealand in the Pacific and also in the Indian Ocean (Tomilin, 1967). Tomilin also states that this species is usually pelagic, inshore movements are usually associated with those of squid, and that the diet includes fish as well as squid. The false killer whale seems to be fairly common, though there are no assessments of the population. It is also subject to occasional directed fishing in both Japan (Miyazaki 1983) and St Vincent (Caldwell et al 1971a). Several conflicts with fisheries are known (see areas 57 61 71 77), and it seems likely that the distribution and feeding habits of this gregarious species could mean that more instances of such conflicts may become known. Mitchell (1975), for example, states that the species “damages fish on longlines, worldwide”.
21 27 31 34 37 41 47 51 57 61 71 77 81 87
Orcinus orca (Linnaeus, 1758) Killer whale
Tomilin (1967) states that the killer whale is a cosmopolitan species found in coastal and oceanic regions from Arctic to Antarctica, though not in the Laptev nor East Siberian Seas. Mitchell (1975) suggests that abundance is greatest within 800 km of the shore in cold waters of both hemispheres.
Dahlheim (1981) states that there are no population estimates available on a worldwide basis, and reviews the biology and exploitation of the species. Hammond (1983) estimates that there are more than 160 000 in Antarctic areas II III IV and V. They have been hunted in many areas of the world (see Mitchell 1975a, Dahlheim 1981), and a few are still taken by Korea, Norway, Japan and also by Iceland for display (IWC 1983 pl68). Descriptions of diet vary with author and location, and notwithstanding Gurevich's (1980) contentions relating to the white whale (see above: Delphinapterus leucas), the killer whale seems to consume a more varied diet than any other cetacean. A review of information on diet is presented by the report of the Killer Whale Workshop (IWC 1982 p628–629). A large number of marine mammal species have been recorded as well as fish and squid. Authors vary as to which groups are most important. The consumption of commercial fish, however is widespread and has led to one of the greatest number of interactions between fisheries and any species of marine mammal (see for example Mitchell 1975a). These are mentioned under sections dealing with areas: 27 34 41 51 57 61 71. Despite this and despite the fact that they are frequently shot at by fishermen throughout their range (e.g. Mitchell 1975a, Goodall and Cameron 1980), there does not seem to be any particular threat to this species, probably due to its relative abundance and catholic diet which precludes a depletion of its food supply.
18 21 27 31 34 37 41 47 48 51 57 58 61 67 71 77 81 87 88
Globicephala melaena (Traill, 1809) Long-finned pilot whale
Found in the North Atlantic from the Barents Sea, Iceland and Greenland, south as far as Cape Hatteras on the east and the Mediterranean on the west (NCC 1980). Apparently absent from the North Pacific at present, it seems to have existed there at one stage, its disappearance remaining a mystery (Kasuya 1975). This same species also exists in the southern hemisphere (Van Bree 1971), from north of the Antarctic convergence in the cold Humboldt, Benguela and Falkland currents (Mitchell 1975). There are no population estimates but Mitchell (1973) believes that the stock around Newfoundland had been depleted due to overexploitation. This species has been subject to a number of hunts and is still taken in the Faroes (IWC 1983 pl68). Sergeant (1962) found that the diet in Canada consisted almost entirely of squid Illex illecebrosus, and cod when this was scarce. Mitchell (1975) also reports another squid, Ommastrephes saggitatus and some fish including the horse mackerel Caranx trachurus and flatfish in stomachs of animals from Britain. Mercer (1967) found the Greenland turbot Rheinhardtius hippoglossoides as a food item in the western North Atlantic in winter. A number of incidental catches have been recorded (see areas 21 27 37).
21 27 (34) 37 41 47 81 87
Globicephala macrorhynchus Gray, 1846 Short-finned pilot whale
Occuring in all tropical and warm waters of the world, this species appears to be allopatric with the previous one. In the Atlantic it ranges as far north as Cape Hatteras, Mauritania and Madeira, south to Angola on the east and possibly around the same latitude in Brazil on the west. It probably occurs throughout the Indian Ocean, and from Peru to the Gulf of Alaska, from Japan to northern Australia in the Pacific (Mitchell 1975). There are no population estimates available, but Mitchell (1975) suggests that the Japanese stock may have been depleted due to overexploitation. A few hundred are still taken in Japan, (IWC 1983 p.168) and some may be taken in the Caribbean (Caldwell et al 1971a).
Kritzler (1952) found that 3 animals had squid in their stomachs and that a fourth kept in captivity ate only squid for some time, eating 20lbs per day. Later it took fish and also grew, eating 45lbs of food per day. He reports that it had difficulty in digesting herring and suggests that the absence of a gall bladder may mean that the species needs lots of fatty food. Some are known to be caught incidentally in Japan (see area 61) but otherwise this species does not seem to interact much with fisheries (see also area 77).
27 31 34 41 47 51 57 61 67 71 77
Lagenorhynchus albirostris (Gray, 1846) White-beaked dolphin
Confined to the North Atlantic from Davis Strait to Massachusetts, and from Iceland and Norway through the Baltic and North Sea to France (Sergeant and Ficher 1957). Tomilin (1967) adds that it is most common in the North Sea, especially the northern part. There are no population estimates, but Mitchell (1975) refers to it as ‘fairly abundant’. The diet consists of fish, (Clupea harengus, Gadus morhua, Merlangius merlangius, Eleginus navaga,), some crustaceans, and some molluscs including cephalopods (Tomilin). There is possibly some by-catch in Iceland (Mitchell 1975a).
21 27
Lagenorhynchus acutus (Gray, 1828) Atlantic white-sided dolphin
As with L. albirostris this species is confined to the North Atlantic. Tomilin (1967) states that it occurs as far north as Spitzbergen and Greenland in coastal waters. Testaverde & Mead (1980) have extended the known southern occurrence of this species in the USA to Chesapeake Bay. Marcuzzi and Pilleri (1971) give the southern limits of its distribution on the eastern side of the Atlantic as the Mediterranean. Mitchell (1975) describes it as abundant at least near Newfoundland and Norway. The diet is said to consist largely of squid and herring (Sergeant & Fisher 1957), whilst Tomilin suggests mackerel and salmonids too, and also relates that vast numbers are known to enter Norwegian fiords chasing herring.
21 27 37
Lagenorhynchus obscurus (Gray, 1828) Dusky dolphin
Mitchell (1975) descibes this as an inshore species with an apparent circumpolar distribution in temperate and cooler waters of South America, South Africa, New Zealand, southern Australia and Kerguelen Island. Mitchell (1975) states that there is no information on the status of the population of this species. As regards diet, Watson (1981) states that they eat ‘fish and squid’, but there appears to be little more information than this. Dusky dolphins are known to be caught incidentally in a number of fisheries (see areas 41 47 87)
41 47 51 57 81 87
Lagenorhynchus cruciger (Quoy & Gaimard, 1824) Hourglass dolphin
There is very little information on this species. Brownell (1974) gives its distribution as pelagic circumpolar in the southern hemisphere, both sides of the Antarctic convergence, but confined to cold water. Watson (1981) describes the species as apparently relatively common in cold southern waters and reports seeing them eating fairly large fish on the surface. There are no reports of interactions with fisheries.
41 47 48 51 (57) (58) 81 87 88
Lagenorhynchus australis (Peale, 1848) Peale's dolphin
Confined to the coastal zone around southern South America and the Falkland Islands. Nothing is known of the status of the population, and the only information on food is that one specimen had octopus in its stomach, (Mitchell 1975). There has been some operational conflict in southern Argentina and Chile with local fishermen which may represent a threat to the population (see areas 41, 87).
41 87
Lagenorhynchus obliquidens Gill, 1865 Pacific white-sided dolphin
Confined to the coastal waters of the North Pacific, from the Bering Sea to California and Japan (Mitchell 1975). Tomilin (1967) states that it eats small gregarious fish such as sardines, herring, salmon, anchovies, saury and jack mackerel, and cephalopod molluscs such as Ommastrephes pacificus. Fitch and Brownell (1968) added the hake Merluccius productus to this list. Mitchell (1975) cites Nishiwaki (1972) who estimates the population in the northwest Pacific to be between 30 and 50 thousand. There are some records of incidental catches of this species (see area 61) as well as the directed Japanese catch of around 250 (IWC 1983 p 168).
61 67 77
Lagenodelphis hosei Fraser, 1956 Fraser's dolphin
Until 1973 there was only one record of this species, from Sarawak. Perrin et al (1973a) reported 5 or 6 new records of the species which has since been recorded a number of times again. Perrin et al suggest a continuous distribution of the species on the high seas of the Indian and Pacific oceans. It has since been recorded in the Atlantic too (Caldwell et al 1976), where it has turned up in the St. Vincent small whale fishery. The only population estimate available is for the eastern tropical Pacific where 7800 animals are estimated to be involved in the tuna seine fishery. Tobayama et al (cited in NCC 1980) have found deep-sea fish and squid in stomachs. Robinson and Craddock (1983) found mesopelagic fish. Leatherwood and Reeves (1983) state that these items as well as crustaceans are eaten at night when they rise to the surface. The only known interactions with fisheries are in the eastern tropical Pacific tuna fishery and in Japan (see areas 61, 77).
31 (34) (41) (47) 51 57 61 71 77
Tursiops truncatus (Montagu, 1821) Bottlenose dolphin
Mitchell (1975) states that distribution is worldwide in temperate to tropical waters, and that the species is mainly coastal but that it may occur far offshore in some areas. There are no overall population estimates, but in some areas the size or status of local stocks has been estimated. Diet varies considerably, but Tomilin describes the species as ‘benthoichthyophagous’, or feeding on bottom fish of the neritic zone, and goes on to suggest that feeding on pelagic fish only occurs where these are in dense enough shoals. Feeding on pelagic fish has been described in Florida by Hoglund (1965). There have been a number of fisheries for this species notably in the eastern U.S.A. and the Black Sea, but exploitation at present is restricted to a few hundred in Japan and possibly a few elsewhere (IWC 1983 pl68). This species is involved in a great number of interactions with fisheries, mostly incidental catches, largely because it feeds in much the same area and often on many of the same fish species as are fished by fisheries (see areas 27 31 37 41 51 57 61 71 77 81 87). No doubt many more are killed in coastal drift nets and beach seines than are recorded so far.
21 27 31 34 37 41 47 51 57 61 71 77 81 87
Grampus griseus (G. Cuvier, 1812) Risso's dolphin
Tomilin (1967) describes this species as rare but widespread in warm and temperate waters of the northern and southern hemispheres. Mitchell (1975) adds that it is generally found in waters deeper than 180 metres, and from Sweden and Newfoundland south to Argentina and South Africa in the Atlantic. The distribution in the Pacific he describes as from the Kurils and British Columbia to Peru and New Zealand, and probably throughout the Indo-Pacific region. Both of these authors agree that Risso's dolphin feeds on squid. There is no information on the status or number of any stocks (Mitchell 1975). There are a few still taken in small whale fisheries in Japan and the Caribbean (Miyazaki 1983, Caldwell et al 1971a) but these probably amount to less than 30 per year (IWC 1983 pl68). There are also however a few reports of incidental catches of this species in some areas (see areas 27 37 61 77). It is unlikely that any other form of interaction could develop in the absence of intensive squid fisheries.
21 27 31 34 37 41 47 51 57 61 67 71 77 81 87
Stenella longirostris (Gray, 1828) Spinner dolphin
Mitchell (1975) describes the distribution of these dolphins as throughout all tropical seas. This species is one of those involved in the tuna seining operations of the eastern tropical Pacific, and as such its population may have been severely affected. In 1978 the total population of two stocks there was estimated at around 2 million animals (IWC 1978 p81), but there are no reliable estimates either for the whole of area 77 nor for the rest of the world. Currently (1981) between 7 and 10 000 animals are taken in seining operations (IWC 1983 p 168). Perrin et al (1973a) report that spinner dolphins feed on mesopelagic fish and epipelagic and mesopelagic squids. A number of other interactions with fisheries have been reported from around the world, though none of these is likely to be of the same magnitude as the tuna seining in the ETP (see areas 31 34 51 57 61 71).
31 34 41 47 51 57 61 71 77 87
Stenella coeruleoalba (Meyen, 1833) Striped dolphin
Occurring from southern Greenland and the North Sea to Rio de la Plata in Argentina and southern African seas in the Atlantic; from the Bering Sea and Siberian waters to California and to New Zealand in the Pacific (Hershkovitz 1966). Watson (1981) also reports seeing large numbers in the Indian Ocean and Leatherwood and Reeves (1983) describe this as the most common cetacean species in the Mediterranean. Again there are few reliable population estimates for this species although there are some in areas where they are caught accidentally or deliberately. Nishiwaki (1975) estimates the Japanese population at between 0.4 and 0.6 million animals and claims that the catch at that time of around 20 000 per year in drive fisheries was not affecting the population. Currently the ‘drive-catch’ in Japan is less than 5 000 per year (IWC 1983 pl68). In the ETP it was estimated in 1978 that there were around 250 000 animals (IWC 1978 p81), but the catch there was never as large as for other species, and is currently only around 60 animals per year, so it may be presumed that the population is not greatly reduced. Miyazaki et al (1973) found that the main food of striped dolphins is small mesopelagic fish, with some squid and shrimp. There are a number of other interactions between this species and fisheries which have been reported, but these are all incidental catches (see areas 27 37 61 77); the diet of this species, which does not seem to include any major commercial species at present is unlikely to bring it into any closer contact with fishing interests.
21 27 31 34 37 41 47 51 57 61 67 71 77 81
Stenella attenuata (Gray, 1846) )
Stenella dubia (G. Cuvier, 1812) ) Spotted dolphins
Stenella frontalis (G. Cuvier, 1829) ) (2 species)
Stenella plagiodon (Cope, 1866) )
There are probably only 2 species amongst these nominal 4 (Mitchell 1975). S. attenuata occurs in the Atlantic, Pacific and Indian Oceans, whilst the other 3 species are confined to the Atlantic. S. attenuata occurs in both coastal and offshore waters of tropical seas, whereas the range of the species group in the Atlantic extends into warm temperate waters (Mitchell 1975). S. attenuata was the species most affected by the ETP tuna seine fishery. There were estimated to be more than 3 million in 1978 (IWC 1978 p 81), with over 150 000 being killed per year in the early 1970's (Mitchell 1975). The number being killed has dropped now to around 25–30 000 per year in the ETP. There is also a small fishery in Japan (IWC 1983 p 168).
There are no other estimates of population size or status for any other stocks of any of the species group. Spotted dolphins associated with tuna in the ETP have been shown to feed on epipelagic fish and epipelagic and mesopelagic squids (Perrin et al 1973a). A number of animals are caught incidentally around the world in different types of fishery (see areas 31 57 61 71 77), but there is always the possibility that large mortalities of these species may recur if dolphin associated tuna fishing is expanded in other areas of the world outside the ETP (see e.g. Caldwell & Caldwell 1971). As surface feeding and frequently coastal feeders, these species are also always open to incidental capture by a number of types of fishery.
31 34 41 47 51 57 61 71 77 87
Stenella clymene (Gray, 1846) Clymene dolphin
Only recently recognised as a valid species, this dolphin is confined to the warm waters of the Atlantic, from New Jersey to the Caribbean and across the tropical Atlantic to West Africa. There are no data on the population size, but the diet is thought to include small mesopelagic fish, especially myctophids (Perrin et al 1981). There are no reported interactions with fisheries yet, but this may be due to the fact that this species has only recently been re-discovered.
31 34
Delphinus delphis Linnaeus, 1758 Common dolphin
Worldwide in distribution, this species occurs from Newfoundland, Iceland and Norway to Argentina and South Africa in the Atlantic; Japan and California to New Zealand and Tierra del Fuego in the Pacific and in the Indian Ocean (Hershkovitz 1966, Goodall 1977, Leatherwood and Reeves, 1983). Tomilin (1967) states that it is most numerous in the temperate waters of the northern hemisphere, but may occur in schools of thousands in the tropics. Estimates of population size are lacking, except in the ETP where a population of at least 1.5 million is estimated (IWC 1978 p 81), (see area 77). Current world catches exceed 8 000 per year (IWC 1983 p 168). Diet varies with location. Tomilin says they eat sprats, sardines and anchovies on the French coast and in the Black Sea, but also lists numerous other species which they are known to take in the Black Sea. Watson (1981) states that they eat mesopelagic fish and squid in the scattering layer. The diet is clearly fairly varied, though mostly of small animals. There are a number of recorded interactions with fisheries around the world (see areas 27 34 37 41 47 51 61 77 81).
21 27 31 34 37 41 47 51 57 61 71 77 81 87
Lissodelphis peronii (Lacepede, 1804) Southern right whale dolphin
Distributed around the southern hemisphere north of the Antarctic convergence and in cold currents as far north as Peru, South Africa and New Zealand (Brownell 1974). Brown (1982) and Cruickshank and Brown (1981) provide descriptions of the known distribution of the species, as well as information on other aspects of the biology. There are no estimates of the population size. Cruickshank and Brown state that the food is thought to be myctophids and squid. There is one record of interaction with fisheries (see area 87). The inaccessability of the species' habitat, and its diet of non-commercial species make any further interactions unlikely.
41 47 48 51 57 58 81 87 88
Lissodelphis borealis (Peale, 1848) Northern right whale dolphin
Tomilin (1967) describes the range as from California and Japan to the Bering Sea. Mitchell (1975) says that it prefers cooler offshore waters. There are no estimates of abundance. Fitch and Brownell (1968) recorded squid and lantern fish (Myctophidae) remains in a sampled stomach. Relatively little is known of this species, like the previous one. There are a few taken incidentally and/or deliberately by Japanese fishermen (see area 61).
61 67 77
Cephalorhynchus heavisidii (Gray, 1828) Heaviside's dolphin
Confined to the coastal seas of South Africa, from Cape Town northwards along the Atlantic coast to Cape Cross (Mitchell 1975). Nothing is known of the status of the population. The diet is suggested to consist of squid and bottom dwelling fish (Mitchell 1975). This species is known to be caught incidentally in a number of fisheries (see area 47).
47
Cephalorhynchus eutropia (Gray, 1846) Black dolphin
Distributed along the coast of Chile from around Concepcion to Tierra del Fuego at least (Aguayo 1975, Goodall 1977). Although nothing is known of the status of this species, Aguayo maintains that it is the rarest of the genus. There appears to be no detailed data on feeding. There is known to be some incidental catch of this species, but the size and effect of this catch have not been determined (see area 41 87).
41 87
Cephalorhynchus hectori (van Beneden, 1881) Hector's dolphin
Found only around the islands of New Zealand in coastal waters (Mitchell 1975), Baker (1978) states that it is often found in muddy waters, less than 8 km from shore, and is commonest in the central eastern part of New Zealand. The status of the species is unknown, but it has been suggested both that it is in decline and that the population is stable (Baker 1978). Again according to Baker, the food consists of pelagic and benthic fish from below the surf zone, including Physiculus bachus the red cod, stargazers and anchovies. Some are known to be taken incidentally in gill net and trawl fisheries of the area.
81
Cephalorhynchus commersonii (Lacepede, 1804) Commerson's dolphin
Brownell (1974) describes the distribution of this species which appears to have a range extending from around Kerguelen Island, South Georgia, the Falklands/Malvinas and the coast of Argentina from Peninsula Valdez to Tierra del Fuego. It is not clear to what extent these populations are isolated from one another. There is no information on the status of this animal, yet Goodall and Cameron (1980) report it around Tierra del Fuego in such numbers that it may be quite common. This species is also taken incidentally by fisheries in Tierra del Fuego (see areas 41 87).
41 48 58 87
Phocoena phocoena (Linnaeus, 1758) Harbour porpoise
Gaskin (1983) has presented a detailed account of the apparent distribution and status of regional populations of this species; he describes the distribution as more or less circumpolar in temperate waters of the northern hemisphere. Reporting various authors' findings, Gaskin gives a northerly limit for the distribution of the species in the Pacific region as the Mackenzie River delta in northern Alaska, and the Chukot Peninsula in the Chukchi Sea. It is apparently rare in the waters of Japan, this, Gaskin suggests, may be the result of over-exploitation, but is frequently found as far south as Monterey in California on the other side of the Pacific. In the northwest Atlantic the harbour porpoise is found as far north as about 70°N in the Davis Strait on the Greenland side, though not apparently this far north on the Canadian side and not in the Hudson Bay. It is said to be common around Iceland and Norway, extending as far north as the White Sea. The southerly limit of the range is about 34°N on the western side of the Atlantic and Senegal and the Cape Verde Islands on the east. A population exists in the Black Sea, considerably reduced by exploitation, but the presence of a population in the Mediterranean is questionable. Gaskin suggests that the number of animals in European Atlantic waters, the Baltic and possibly the North Sea have declined in recent years, for unknown reasons, although it is still common in both Norway and the Azores. The diet of the harbour porpoise has been summarised by Gaskin et al (1974) and includes a large number of fish species, which Mitchell (1975) describes as ‘mainly smooth, non-spiny fish especially gadoids and clupeoids’. The harbour porpoise is also regularly taken incidentally, often in quite large numbers, throughout most of its range (see areas 21 27 61 67 77)
18 21 27 34 37 61 67 77
Phocoena sinus Norris and McFarland, 1958 Cochito
Restricted to the Gulf of California in Mexico, and more abundant in the northern part of the Gulf (Mitchell 1975). This is not a particularly numerous species though no population estimate is available. The diet is known to include striped grunts Orthopristis reddingi, and gulf croakers Bairdiella icistius, as well as squid (Brownell 1983). Between 10 and 100 are taken accidentally in gill nets per year (see area 77), and this according to Brownell, may represent a substantial impact on a local and relatively small population.
77
Phocoena spinipinnis Burmeister, 1865 Burmeister's porpoise
Distributed around the coast of southern South America, from Punta del Diabolo in Uruguay (Pilleri & Gihr 1972) to Tierra del Fuego (Goodall 1977) and up the coasts of Chile and Peru to around 5°S (Aguayo 1975). It has been considered as possibly the most numerous small cetacean in this area (Brownell and Praderi 1982), but there are no estimates of the size of the population. The diet is known to include Merluccius hubbsi, Pagrus sedecim and squid (Brownell and Praderi 1982). This species is taken in large numbers both accidentally and deliberately, particularly off Peru (see areas 41 87), but the effect of this catch on the population is not known.
41 87
Phocoena dioptrica Lahille, 1912 Spectacled porpoise
Known only from only a few individuals and originally thought to be confined to the South West Atlantic (Brownell 1974), this species has since turned up in New Zealand (Baker 1977) and possibly in the Indian Ocean off South Africa (Frost and Best 1976). In the South Atlantic it is known from Tierra del Fuego (Goodall 1977) as well as the Falklands, South Georgia and Uruguay (Brownell 1975a). It is not clear whether these populations are isolated from one another, and there is no information on the status of the species, though the number of times it has been recorded (about 15) indicates that it may not be very common. There is nothing known of the food habits either. Some are known to be taken in Argentinian tangle nets (see area 41).
41 48 51 81
Phocoenoides dalli (True, 1885) Dall's porpoise
Common in inshore cold waters of the North Pacific, but also found out to about 500 miles, this species ranges from Baja California around the North Pacific via Alaska, the Bering Sea, sea of Okhotsk and eastern sea of Japan to Honshu (Mitchell 1975). Bouchet (1983) estimates the population in the North Pacific and Bering Sea to be between 790 000 and 1 738 000 by a strip-transect method. Wilke and Nicholson (1958) found myctophid lantern fish and squids to be the most important food items in the diet. This species is taken in large numbers by the salmon gill net fishery (see areas 61 and 67), but the effect of this on the population is unclear.
61 67 77
Neophocoena phocaenoides (Cuvier, 1829) Finless porpoise
A coastal and riverine species found in the major rivers and around the coasts of the region bounded by the Arabian Peninsula, Indonesia, and Japan, and including Oman, Pakistan, India the Philippines and China as well as most other countries in the region. There is also some dispute as to whether its range extends to South Africa (NCC 1980). Baker (1972) suggests that it may occur as far south as New Zealand. There is no information on the overall population size, but the numbers around Japan have been estimated at between 1 600 and 4 900 (Kasuya and Kureha 1979, cited in NCC 1980), and may be common in other parts of its range (NCC 1980). The diet is said to consist of small squids and cuttlefish, crustaceans and some small fish such as sandlance (Mitchell 1975). There is some reported interaction with fisheries in Japan, Australia and the Indo-Pakistan coast (see areas 51 61).
51 57 61 71
Platanista gangetica (Roxburgh, 1801) Ganges susu
Mitchell (1975) describes the distribution of this species as “throughout the Brahmaputra and Ganges river systems”. Its range extends up to the Himalayas, to Nepal and possibly Bhutan, and down to the estuaries in Bangladesh and India (NCC 1980). The total population has been estimated at around 4 – 5 000, with the population in the Ganges having declined (Jones 1982). The food species are unknown, but said by Mitchell (1975) to be probably fish and shrimps. This species is known to get caught in nets of river fishermen (see area 57), but the extent of this is unknown.
57
Platanista minor Owen, (1854) Indus susu
Confined mainly to the lower reaches of the Indus River in Pakistan, the range used to cover the entire river system to the foothills of the Himalayas (NCC 1980). The population is now isolated into a number of groups by the building of barrages along the river (Mitchell 1975a). Kasuya and Nishiwaki (1975) have estimated the population at between 450 and 600, with a decline of 10% per year at that time. The food of this species is unknown, but Pilleri's (1972) specimens ate between 1 – 1.4 kg of fish per day. They are still apparently killed in nets of fishermen (see area 51).
51
Inia geoffrensis (de Blainville, 1817) Boutu
Found throughout the Amazon and Orinoco river systems in South America, including the tributaries upstream in Bolivia (Mitchell 1975). Traditionally the species was given some superstitious protection from such hunting. Mitchell states that the stocks of this species might be near original levels but Leatherwood and Reeves (1983) state that increased numbers of this dolphin are being killed by settlers in the Amazon region, who are not inhibited by traditional taboos. Food is known to consist of characins and catfish, as well as crustaceans (Mitchell, Leatherwood and Reeves). There are also known to be some mortalities of this species in gill nets, and it has been claimed that the species cooperates with fishermen (see areas 41 31).
31 41
Lipotes vexillifer Miller, 1918 Beiji
Pei-Xun (1981) provides an account of this little studied species. It is confined to the middle and lower reaches of the Chianjiang River in China. The population is said to be small, with only one animal seen per 10 km. Pei-Xun describes it as rare. Brownell and Herald (1972) describe the contents of one stomach as being catfish, but there is little more information than this concerning the diet. The species is thought to be declining due in part at least to the conflict with local fisheries (see area 61).
61
Pontoporia blainvillei (Gervais & d'Orbigny, 1844) Franciscana A coastal species ranging from the Peninsula Valdez in Argentina to the tropic of Capricorn in Brazil (NCC 1980), extending out as far as the 20 fathom curve (Leatherwood and Reeves, 1983). There are no estimates of abundance available. The food is described in detail by Brownell and Praderi (1976) and includes the species Engraulis anchoita, Cynoscion striatus, Trachurus lathami, Porichthys lathamis, and other Anchoa species. There is some by-catch by a local shark fishery which may have a significant effect on the Franciscana population (see area 41)
41
Eumatopias jubatus (Schreber, 1776) Steller sea lion
Distributed around the edges of the North Pacific from the Sea of Japan northwards to around 66° North, and then south around the coast of the USA and Canada to San Miguel Island, California. The total population is estimated to be around or in excess of 230 000, the bulk of which population (200 000) is found in Alaskan waters. The population in southerly areas is smaller and may be declining as the population recedes northward (Mate and Gentry, 1979). Approximately 15 000 animals are killed in Alaska, Japan and the USSR, mostly in fishing operations (Mate 1982a). The diet is said to consist mostly of non-commercial fish species and cephalopods, but may also include some commercial species such as salmon (Fiscus & Baines, 1966). Wilke and Kenyon (1952) also found small gadids, flatfish and sandlance in 2 stomachs they examined. Schusterman (1981) cites Keyes' (1968) review of feeding date for this species and includes flounder, halibut, cod, pollock, smelt and greenling. Schusterman also cites Mathison et al (1962) who found that 27% of the diet was fish, 35% cephalopods, 20% bivalves and 8% shrimps and crabs. Some conflict is known between this species and fishermen (see areas 61 67 77).
61 67 77
Zalophus californianus (Lesson, 1828) California sea lion
According to Mate (1979) there are three breeding sub-populations of this species. The northerly limit of the range of the Californian/Mexican population is British Columbia (51°N), which is reached by post breeding males. The limit of the breeding season range is around 34°N, and some males apparently also migrate south as far as Manzanillo in Mexico (19°N). The Galapagos group breeds in and inhabits the area around the Galapagos Islands, and the third group, which bred in the Sea of Japan may be extinct. This species is also known to exist in small numbers on the eastern seaboard of the USA, having escaped from captivity, but apparently has not yet bred there (Caldwell et al 1971). Mate (1982) indicates a total Californian/Mexican population of around 75 - 100 000 animals, and a Galapagos population of around 20 000; the former, after some quite heavy exploitation last century may now be increasing and expanding its range northwards. He also describes this species as a shallow water opportunistic feeder, whose main foods are thought to be squid, including Loligo, and small fish such as Engraulis, Merluccius, Clupea, and various small rock fish. Bailey and Ainley (1982) have confirmed the importance of Merluccius productus in the diet. There are a number of known interactions between this species and commercial fisheries in the California region (see areas 67 and 77).
31 (61) 67 77
Otaria flavescens (Blainville, 1820) South American sea lion
Distributed around the coasts of South America from around 23°S on the Brazilian coast southwards to Tierra del Fuego, and then north to around 4°S on the coast of Peru (Scheffer 1958). The total population has been estimated from various authors to be around 273 000 animals (Vaz-Ferreira 1979), 2/3 of this total being in Argentinian waters. The population structure has changed historically, having decreased in some places such as the Falkland Islands, but increased in others such as Peru since the end of commercial exploitation. Some exploitation still occurs in Uruguay and possibly Peru (Vaz-Ferreira 1979). Vaz-Ferreira (1982) summarizes the knowledge of the diet of this species. It is known to include fish, molluscs and crustaceans. Amongst the fish commonly eaten are Sebastodes oculatus, Merluccius gayii, Clupea bentinckii and Engraulis anchoita, as well as bottom fish, squids, and at least occasionally, penguins. There are known to be conflicts between this species and fishermen throughout most of its range, particularly with regard to damaged nets and catch (see area 41 and 87).
41 87
Neophoca cinerea (Peron, 1816) Australian sea lion
Scattered around the southern coast of Australia, this species breeds mostly on islands, with one colony on the mainland of south Australia. The most westerly colony occurs off West Australia (about 28°S) and the the range continues around the south coast to Kangaroo Island off Adelaide (138°E) (King and Marlow 1979). Warneke (1982) estimates the total population at between 3 and 5 thousand. King and Marlow state that the diet is known to consist of local fish and squid, and both penguins and the fiddler ray (Trygonorhina sp.) have been noted as food items too (Warneke 1982). There is some conflict recorded between this species and fishermen (see area 57).
57
Phocarctos hookeri (Gray, 1844) Hooker's sea lion
Marlow and King (1979) state that this species is centred on the Auckland Islands 300 miles south of New Zealand, and also occurs in a few other sub-antarctic islands (the Snares and Campbell Island) as well as straggling as far as Macquarie Island. The population they estimate to be around 4 000 animals, which is possibly stable. Yaldwyn (1958) reports cephalopods, prawns, crayfish and crabs in the diet. Penguins have also been eaten occasionally (Marlow and King 1979). There is some interaction with fishermen in the region (see area 81).
81
Callorhinus ursinus (Linnaeus, 1758) Northern fur seal
Lander (1979) states that this species breeds in the high latitudes of the North Pacific on the Commander, Pribilof, and Kuril Islands, as well as Robben Island and San Miguel Island. In the winter they migrate south to the Japanese and American coasts as far as about 34°N. Lander estimated the total population as around 1,765,000 animals, nearly 3/4 of which breed in the Pribilof Islands and migrate to American waters in the winter. This species is exploited on a sustained management basis. During winter Wilke and Kenyon (1952) found that the diet of 148 animals examined consisted of around 99% herring whilst the remainder was pollack Theragra chalcogramma. Lander (1979) however states that food varies with season, age and area and consists of a number of items including squid, herring, hake, anchovy, sandlance, capelin, walleye pollack, atka mackerel and deep sea smelt. Perez and Bigg (1981) provide a detailed account of the feeding of this species, and suggest that Pacific hake Merluccius productus, northern anchovy Engraulis mordax, Pacific saury Cololabis saira, rockfish Sebastes, herring, salmon, and capelin, as well as a number of squid species are all important in the diet. There are reported interactions between this species and commercial fisheries (see areas 61 67 77).
61 67 77
Arctocephalus townsendi Merriam 1897 Guadaloupe fur seal
Restricted to a small part of the former range, this species breeds now only on part of the Isla Guadaloupe, Baja California, although individuals have been sighted in other areas around Baja California, particularly San Miguel Island (Peterson et al, 1968, cited by Hubbs 1979). Hubbs estimates the population size to be possibly more than 500, which is thought to be increasing. The species is fully protected, after nearly having been driven extinct by commercial sealing operations which destroyed the ca. 200 000 strong population. There is apparently no information on the feeding habits of this species, neither is there any record of interactions with fisheries. Such interactions, however cannot be ruled out especially for an increasing population.
77
Arctocephalus philippii (Peters, 1866) Juan Fernandez fur seal
This species is closely related to the preceding one (Repenning et al 1971), and is confined to the Juan Fernandez Archipelago off the coast of central Chile. The population is thought to number fewer than 1 000, possibly around 750, having been reduced from extremely abundant levels 300 years ago after the slaughtering of several million up to 1824. The population may be increasing at present (Aguayo 1979). Aguayo also states that the diet is thought to consist of several kinds of fish, cephalopods and a local spiny lobster (Jasus frontalis). There is some evidence of a number being killed by local fishermen (see area 87).
87
Arctocephalus galapagoensis (Heller, 1904) Galapagos fur seal
Confined to the Galapagos Islands, this species has also been nearly exterminated by commercial sealing since 1535. The population may have increased to as many as 5 000 at present, though other estimates have put the population at around 1 000. Clarke and Trillmich (1980) found that the diet is exclusively cephalopods, 94.6% of it ommastrephid squids. There are no records of interactions with fishermen. The species is anyway fully protected (Clark 1979).
77
Arctocephalus australis (Zimmerman, 1783) South American fur seal
Distributed around the coast of southern South America, from Rio de Janeiro in Brazil, southwards, including the Falklands/Malvinas Islands, to Tierra del Fuego, and then up the coast of Chile and Peru as far as Lima (Repenning et al 1971). The total population may exceed 320 000, 252 000 of which breed in Uruguay, and is thought to be increasing overall (Vaz-Ferreira 1979a). The population is managed in Uruguay, around 8 000 – 10 000 being taken per year (FAO 1983). Vaz-Ferreira goes on to state that the diet is known to include a number of fish species such as Engraulis anchoita, Trachurus lathami, Cynoscion striatus, Pneumatophorus japonicus, and Peprilus sp., as well as some cephalopods and crustaceans. Feeding takes place over a wide area of the continental shelf and beyond. Vaz-Ferreira (1982a) indicates that fur seals cause little or no disturbance to commercial fishing operations.
41 87
Arctocephalus pusillus (Schreber, 1776) Cape fur seal/Australian fur seal
There are two sub-species recognised, A. pusillus pusillus and A.pusillus doriferus (Repenning et al 1971). The former breeds along the coast and on offshore islands of Namibia and South Africa, wandering as far north as Angola and as far east as East London (28°E) (Shaughnessy 1982), and the latter ranges from around 152°E on the coast of New South Wales to about 138°E via southern Tasmania (Warnecke 1982). The populations are apparently isolated from one another. The total population of A.pusillus pusillus is estimated to be about 850 000, or 73% of the initial population size with an annual kill of around 78 000 pups (Shaughnessy 1979). The Australian population is estimated at around 20 000 and may now be stable (Warnecke 1982). Rand (1959) found that small schooling fish make up 60% of the volume of all food consumed, and gives a detailed analysis of the diet. The diet of the Cape fur seal consists largely of fish, and also squid, food species including Trachurus trachurus, Loligo spp., and pilchards (Shaughnessy 1979). The Australian fur seals' diet is less well known but may consist largely of squid (Notodarus, Sepioteuthis) as well as a variety of fish species such as barracouta (Thyrsites), and occasionally a number of other small fish species, e.g. red mullet, pilchards and parrot fish. Both of these subspecies are known to interact to some extent with fisheries, especially in South Africa (see areas 47 57 81).
47 57 81
Arctocephalus forsteri (Lesson, 1828) New Zealand fur seal
There are two geographically isolated populations of this species also. Breeding groups are distributed on islands around the southern coast of Australia, from the south western tip of Western Australia (117°E) to Kangaroo Island in South Australia. The second population is distributed around the coast and surrounding islands of South Island in New Zealand, and some of the subantarctic islands such as Macquarie, Chatham, Bounty, Stewart, Antipodes and Auckland Islands. In winter the range extends northwards along the coasts of North Island to 34°S (Crawley & Warneke, 1979). The Australian stock size is unknown, but it may not exceed a few thousand individuals, and is thought to be stable (Warneke, 1982). The New Zealand stock has been estimated at around 38 000 and is thought to be recovering from decimation last century (Crawley & Warneke, 1979). According to Warneke (1982) the diet consists mostly of barracouta (Thrysites), and also some octopus, squid and other small fish. Some conflict with fisheries may occur throughout the range (see areas 57, 81).
57 81
Arctocephalus gazella (Peters, 1875) Antarctic fur seal
The species is distributed on islands south of the Antarctic circle, including South Georgia, South Orkney, South Sandwich, Bouvetoya, South Shetland, Heard and McDonald Islands and possibly Kerguelen. The population is thought to be increasing rapidly following decimation by commercial sealing operations and was estimated to be around 363 000 in 1976, 350 000 of which are from South Georgia (Bonner 1979). Bonner (1982) suggests a total projected population stabilizing at around 1.5 – 2.5 million animals. The food is thought to be largely krill, but some fish, birds and squid are also known to be eaten (Bonner 1979). There are no well documented interactions with fisheries, but these could materialise if krill fishing is intensified in the region (see areas 48, 58, 88).
48 58
Arctocephalus tropicalis (Gray, 1872) Subantarctic fur seal
Known to breed on a number of subantarctic islands including Gough, New Amsterdam, St Paul, Prince Edward and Marion Islands, as well as Nightingale and Inaccessible Islands and occasionally on Tristan da Cunha, this species is also occasionally reported from the South African coast, Macquarie Island, the Crozet Archipelago and South Georgia (Bonner, 1979a). Shaughnessy (1982a) estimates the total population to exceed 23 400, whereas Bonner (1979a) gives a figure of more than 120 000. The population appears to be thriving after near extinction last century (Laws 1973). Rand (1956) found cephalopods to be the most important group in the diet of this species, which also included euphausiids and some nototheniid fish. According to Shaughnessy (1982a) other authors have described penguins in the diet too. There are no records of interaction with fisheries, and Shaughnessy (1982a) regards these as unlikely.
47 51 57
Odobenus rosmarus (Linnaeus 1758) Walrus
Two or possibly three sub-populations are recognised, in the Atlantic and Pacific oceans, and possibly the Laptev Sea. Distribution in the Atlantic is from the eastern Canadian Arctic and West Greenland, to Spitzbergen, Franz Josef Land, and the Barents and Kara Seas. In the Pacific area the distribution ranges from the Bering and Chukchi Seas to the Laptev Seas. The Pacific stocks are thought to number around 140 000, whilst the Atlantic stocks are thought to number less than 20 000. The stocks are thought to be recovering at present from over-exploitation, though a few thousand are probably still taken every year. The diet of the walrus consists of benthic invertebrates taken in shallow waters, especially molluscs, echinoderms, tunicates, crustaceans, echiuroids and priapulids, up to 45 kg of food being eaten per day. (Brenton 1979). Although there is no reported interaction with fisheries at present, development of mollusc fisheries in Arctic waters could affect walrus populations (Harwood 1981) (see areas 18 61 67).
18 21 27 61 67
Phoca vitulina Linnaeus, 1758 Harbour seal
A widespread species found from Iceland, Norway, Britain and the East Atlantic as far south as the southern North Sea, and also in the Baltic, sparsely. In the West Atlantic the species occurs from Maine northwards up the coast of Canada and West Greenland to Hudson Bay and the Arctic Circle. In the Pacific the range extends from Baja California northwards to Bristol Bay and Herschel Island in Alaska. Also found in the Kuril Islands, northern Hokkaido, and the Aleutian Islands. There are thought to be around 400 000 worldwide more than half of which are found in Alaska, with around 30 – 50 000 on each side of the Atlantic also; the population may be stable. A few thousand are taken in kills every year. The diet is extremely catholic with a wide range of pelagic and demersal fish taken as well as cephalopods and crustacea. Gadids, clupeids, pleuronectids, salmonids and other fish of commercial importance are all included in the diet. (Bonner 1979c). There is some interaction with fisheries, as this species is both caught in nets (e.g. Naito, 1976) and also eats commercial fish species (see areas 21 27 61 67 77).
18 21 27 31 61 67 77
Phoca largha (Pallas, 1811) Largha seal
Some authors regard this as a sub-species of P. vitulina, (e.g. Naito, 1976), it is distributed throughout the Sea of Okhotsk, Bering Sea, Chukchi Sea, Mackenzie Sea, Po Hai Sea and the north western part of the Yellow Sea, this species also occasionally turns up off the Japanese and Korean coasts. It is more closely associated with ice than the harbour seal, as it breeds on ice rather than land. The total population is unknown, but is thought to exceed 250 000 at least. There is a small amount of hunting at present. There is not much information on the diet of this species, but it is known to feed on fish, including salmon, as well as cephalopods and crustacea. (Bonner 1979b). There are records of some interaction with fisheries (see area 61).
18 61 67
Phoca hispida (Schreber, 1775) Ringed seal
There is a circumpolar distribution in the Arctic, often closely associated with the ice. Southern limits are marked by the Sea of Okhotsk, the northern Bering Sea as far as the pack ice, into the Hudson Bay, around Greenland and as far south as Labrador, the sea-ice of Eurasia, the upper reaches of the Baltic Sea, and Lakes Ladoga and Saimaa. (Stirling and Calvert 1979). Frost and Lowry (1981) describe the populations in Lakes Saimaa and Ladoga, in the Okhotsk Sea and in the Baltic as subspecies, P.h.saimensis, P.h. lagodensis, P.h.ochotensis and P.h. botnica respectively. This is said to be the most abundant of Arctic Ocean seals, with a total population of around 6–7 millions, which is thought to be fairly stable. Tens of thousands are harvested each year for their pelts (Stirling and Calvert 1979). Popov (1982) states that polar cod (Boreogadus saida) may account for around 90% of the diet in winter in northern European waters, other species being eaten then including navaga, smelt, sand eel and flounder. In summer crustaceans form the main part of the diet. In other areas, such as the White and Barents Seas, the main food items may include commercial species such as herring and navaga. Similar species are consumed in the Pacific. Salmon are also eaten, especially around the Kola Peninsula. There are records of incidental catches too (see areas 27 and 61).
18 21 27 61 67
Phoca sibirica (Gmelin, 1788) Baikal seal
Confined to Lakes Baikal and Oron, there are an estimated 50 – 60 000 seals, mostly in Lake Baikal; an annual kill takes 2 – 3 000 (Popov 1982). Popov (1982) describes the diet of this species as being Comephoris baicalensis, 72% of the diet by weight, with the rest (25%) being made up mostly from sculpin (Cottus sp.). Commercial species are said to make up less than 1% of the diet. There are no reported interactions with fisheries (Popov 1982).
04
Phoca caspica (Gmelin, 1788) Caspian seal
Confined to the Caspian Sea, with an estimated total population of around 500–600 000. There is an annual kill of around 60 – 65 000 pups. The diet is varied, but sprat Clupeonella delicatula is said to be the main food, whilst other species which are eaten are known to include small fishes such as bullheads, sand smelts, herring, roach, carp, pike-perch, shrimp, amphipods and crayfish. There are thought to be no interactions with fisheries. (Popov 1982).
04
Phoca groenlandica (Erxleben 1777) Harp seal
Three stocks are recognised in this species, one centred on the pack ice of the White Sea, another around Jan Meyen Island, and a third around Newfoundland and the Labrador coast in Canada. During summer, feeding animals range northwards following receding pack ice, up as far as Thule in West Greenland, and in the northern Barents Sea and Kara Sea north to Svalbard. All three stocks are hunted, about 40 000 animals, mostly pups, being taken from the White Sea population every year, about 10–15 000 pups from the Jan Meyen stock, and about 150 000 pups from the Newfoundland stock, which is much the largest of the 3. (Lavigne 1979). There has been some considerable debate over the size of pup production in each area, and hence the inferred size of the populations, but it would seem that the total population is somewhere between 1.2 and about 2.5 million animals (ICES 1982). Beddington and Williams (1980) have summarised information on Harp seal
feeding in the Northwest Atlantic. The diet is varied and includes crustaceans when young, especially Thysanoessa spp., and Pandalus borealis. Fish consumed include Capelin Mallotus villosus to a large extent, but also herring, cod, flatfish and redfish. Lavigne (1979) points out that arctic cod (Boreogadus saida) are important items in higher latitudes, whilst Popov (1982) also states that Arctogadus glacialis and Mallotus villosus are important foods in the White and Barents Seas. Cephalopods are also eaten, but it is unclear how important they are in the diet overall. There have been a number of reported interactions between this species and fisheries (see areas 21, 27).
18 21 27
Phoca fasciata Zimmerman, 1783 Ribbon seal
Found in the Sea of Okhotsk and Bering Sea, and toa lesser extent in the Chukchi Sea, this species ranges as far as the limit of the drifting pack ice. There is some commercial harvest around 9 000 being taken in the Bering Sea, and an unknown number in the Sea of Okhotsk. The population has been estimated at between 200 – 250 000 animals, and could be declining. The diet is reported to include crustaceans (shrimps, crabs and mysids), followed by fish (including Boreogadus saida, Theragra chalcogramma, and Gadus macrocephalus in the sea of Okhotsk) and cephalopods in third place (Burns 1981). There does not appear to be any appreciable interaction between this species and commercial fisheries.
18 61 67
Erignathus barbatus (Erxleben, 1777) Bearded seal
This species has a circumpolar Arctic distribution, preferring moving pack ice over shallow waters, and is known to wander as far south as Scotland, the Gulf of St Lawrence, Hokkaido and Norway. There are no estimates of world population, but this probably exceeds 500 000. The annual kill of this species exceeds 10 000, and it may be declining in some areas (Stirling and Archibald 1979). Popov (1982) states that this species is known to eat more than 70 species, including fish (especially polar cod, but also herring, navaga, flounder and sand eel), molluscs, crabs, shrimps and worms. There are some minor interactions with fisheries reported (see area 61).
18 21 27 61 67
Cystophora cristata (Erxleben, 1777) Hooded seal
The hooded seal breeds off Jan Meyen Island, and off Newfoundland, in the Davis Strait, and in very small numbers in the Gulf of St Lawrence and the southeast Bering Sea. It may be found along both coasts of Greenland in summer. The Jan Meyen population is apparently the larger of the two, with a pup kill of around 30 000 per year, whilst about half this number are taken from the Newfoundland population (Sergeant 1979). The data is not sufficient for any population assessment to be made on the basis of the pup kills and associated tagging programmes (Goodman 1982), but the total population presumably numbers in hundreds of thousands for such a pup kill to be operable over the number of years it has done so. Indeed Popov (1982) maintains that the total population numbers 500 – 600 000 animals, 80 – 90% being in the Jan Meyen stock. There is also argument over whether the level of the kill is affecting the population stability at present (ICES 1983). The diet consists of Gonatus fabricii, Sebastes marinus (redfish), Rheinhardtius hippoglossoides (Greenland halibut), Mallotus villosus (capelin), and Boreogadus saida (polar cod) (Sergeant 1979), as well as herring, salmon, tusk, starfish, catfish, sandeels, rays, amphipods and whelks (Oritsland, pers. comm.). There are some minor interactions with fisheries (incidental catches in salmon nets) reported, but Sergeant implies that the low stock size, catholic diet and migratory habits make anything more dramatic very unlikely (see areas 21 and 27).
18 21 27
Halichoerus grypus (Fabricius, 1791) Grey seal
Three stocks have been identified, a West Atlantic stock distributed around the Gulf of St Lawrence, Newfoundland, and the Maritime States, a Baltic stock confined to the Baltic Sea and an East Atlantic stock which breeds mainly around Britain, especially Scotland, but which also extends to Iceland, Norway, and around to the north coast of Russia, as well as to Ireland and the Faroes. This last stock is much the largest of the three (Bonner 1979d). Both the East and West Atlantic stocks are thought to be increasing at present after severe reduction last century (Bonner 1979d), whilst the Baltic stock is decreasing and at present may number no more than 3 – 5 000 (Stenman 1978). The British population is said to comprise 60% of the entire population (Bonner 1981a), and in 1983 the Sea Mammal Research Unit estimated the number of breeding grey seals in the British Isles to number around 80 000, suggesting a world population of about 130 000 animals.
The diet is known to include salmon and cod, but recent studies have shown these two items are probably trivial in the diet of seals in British waters (see area 27). The most important food species were found to be small so-called ‘industrial’ fish, especially the sand eel Ammodytes, but other fish including whiting and ling were also important (NERC 1984). Bonner (1981a) also lists skates, cephalopods and crustacea as important food items in some studies. The grey seal has been implicated in a number of controversies with fisheries (see areas 21 and 27).
21 27
Monachus monachus (Hermann, 1779) Mediterranean monk seal
Formerly abundant in the Mediterranean, Black Sea and along the coast of North West Africa, this species has now been reduced to a handful of isolated groups within its former range, notably some of the islands off north West Africa, and also some of the Greek Islands (Boulva 1979). The total population size is unknown but has been estimated from visual surveys to be around 5 – 800, and declining steadily (Ronald and Healey 1982). The diet is said to include eel, carp, whiting, sardine, bonito, octopus, lobster, Dentex, Labra, whitefish, Mullus surmuletus, Boops boops, Mugil cephalus, and other fish, including flatfish, species. (Boulva 1979). There has been some record of interaction between fishermen and this species in the Mediterranean (see area 37).
27 34 37
(Monachus tropicalis (Gray, 1850) Caribbean monk seal
Considered to be extinct, this species was once found in the Caribbean and Gulf region from the Bahamas to Florida, and to the Yucatan and Nicaragua. None have been positively identified since 1952 (Boulva 1979).)
31
Monachus schauinslandi (Matschie, 1905) Hawaiian monk seal
The Hawaiian monk seal is found on a number of islands to the west and northwest of Hawaii, with numbers probably declining due to disturbances by man (Kenyon 1972). The latest population estimate based on visual surveys put the total population at around 700 – 1 000 animals. Little is known of the diet, but it is thought to include cephalopods and reef bottom fish. (Brenton 1979a). There are some indications of gear conflicts (see area 77).
77
Mirounga leonina (Linnaeus, 1758) Southern elephant seal
Laws (1979) states that there are three main stocks, centred on South Georgia, but including parts of mainland South America, the Falklands and the Scotia arc, numbering around 300 000; on Kerguelen and Heard Islands, numbering around 200 000 and a third stock on Macquarie Island and the New Zealand subantarctic islands, numbering about 100 000. The populations are thought to be more or less stable. The diet of elephant seals consists of both fish and squid. Pascal (1984 in press) has suggested that fisheries may have affected the population dynamics of the Kerguelen stock, but this has been disputed by McCann (1983) (see area 58).
41 48 57 58 81 88
Mirounga angustirostris (Gill, 1866) Northern elephant seal
Ranging as far north as British Columbia, and at least 240 km from the shore, the breeding sites of this species are confined to offshore islands from Baja California to central California. The population is at present estimated to number 45 000, and is still increasing fast from a low point of less than 100 individuals in the late nineteenth century (Le Boeuf 1979). The diet is known to consist of a number of fish including bottom fish and elasmobranchs, and also some squid (Morejohn and Baltz 1970). Some gear interactions have been recorded (see area 77).
67 77
Lobodon carcinophagus (Hombron & Jacquinot, 1842) Crabeater seal
Confined to the Antarctic pack ice, this is thought to be the most numerous of all pinniped species, with a total population of around 15 million animals. Since the reduction of the baleen whale stocks in the Antarctic, this species may have increased in abundance. The food is almost exclusively krill, mostly Euphausia superba (Laws 1979a). There are no recorded interactions with fisheries, apart from the possible reaction to commercial whaling already mentioned. It is worth noticing, however, that any predation on commercial species (krill) might be significant merely as a consequence of the size of the population.
48 58 88
Ommatophoca rossi (Gray, 1884) Ross seal
Generally restricted to the consolidated ice pack of the Antarctic, one individual has been sighted north of 55oS, at Heard Island. The world population may number around 220 000, which is possibly stable. The food is thought to consist of cephalopods (Laws and Hofman 1979). There are no interactions between this species and fisheries at present.
48 58 88
Hydrurga leptonyx (de Blainville, 1820) Leopard seal
The distribution of this species is similar to that of the crabeater seal, i.e. throughout the unconsolidated pack ice of the Antarctic. Stragglers, however, have been sighted in most of the southern continents; it is also reasonably abundant on the subantarctic islands. The world population may be as much as 500 000. The diet is known to consist of penguins and seals, as well as krill, but the relative importance of these items is not known. It is possible that the crabeater seal is the main food supply of adult animals (Hofman 1979). There are no recorded interactions between this species and any fishery at present.
47 48 57 58 81 88
Leptonychotes weddelli (Lesson, 1826) Weddell seal
This species inhabits the fast ice region of the Antarctic, but is also known to breed as far north as South Georgia. There have also been sightings in Uruguay, the Falklands, the Juan Fernandez Islands, New Zealand, South Australia, Macquarie Island and Heard and Kerguelen Islands. The world population is estimated as at least 750 000, which is an underestimate, as inshore regions have not been surveyed. The food is thought to consist largely of fish, including the species Dissostichus mawsoni, Trematomus sp. and Pleuragramma antarcticum (De Master 1979). As yet the lack of fisheries in the areas inhabited by this species has meant that there are have been no recorded interactions.
41 48 57 58 81 87 88
Trichechus senegalensis (Link, 1795) West African manatee
Husar (1978) describes the distribution of this animal as from Senegal to Angola, along the West African coast, in river estuaries and in rivers for up to several hundred miles in places. There are no population estimates nor estimates of abundance, but Husar describes the population as severely reduced, although in areas it may still be present in considerable numbers. Although it is protected in most areas now, there is still continued illegal hunting in many areas. The animals are said to prefer shallow weedy estuaries, as they feed on vascular aquatic plants (Husar 1978). Shark netting is said to have a considerable effect on this species (see areas 34 47).
34 47
Trichechus manatus (Linnaeus, 1758) Caribbean manatee
Bertram and Bertram (1973) describe the distribution of this animal as from North Carolina, through Florida to Texas in the Gulf of Mexico, along the Caribbean and Atlantic coasts of Central America, as far as the Guianas and the Atlantic coast of northern Brazil, and to the Bahamas and Greater Antilles. There are no estimates for the total population, but this is thought to be declining throughout the range (FAO 1978). The population in Florida is thought to number about 1 000 (Campbell and Powell 1976). The food is aquatic vascular plants, in freshwater and salt water (FAO 1978). The decline in the population may in part be due to local fisheries (see area 31).
31
Trichechus inunguis (Natterer, 1883) Amazonian manatee
The Amazonian manatee is confined to the Amazon river basin, and possibly in the Orinoco (FAO 1978). A minimum estimate of 10 000 animals has been suggested (IUCN 1976) sparsely distributed throughout the range. The population is said to be severely reduced. The diet of this animal is the same as other sirenia, aquatic vascular plants. (FAO 1978). Fishing operations are known to affect this population (see areas 41).
41 (03)
Dugong dugon (Muller, 1776) Dugong
Bertram and Bertram (1970, 1973) describe the distribution of this species as from Madagascar and Mozambique in shallow coastal waters up the African coast to the northernmost end of the Red Sea, eastwards through India to southeast Asia, north to the Ryukyu Islands, and south and east to Yap, Guam, Papua New Guinea and New Caledonia, and south to the north, east and west coasts of Australia. There are no estimates of total population, but Bertram and Bertram (1970) describe it as rare throughout the range, except in northern Australia and Papua New Guinea. The diet is the same as for manatees. The decline of this species has been precipitated in part by fishermen, and throughout the range accidental nettings are an important source of mortality (FAO 1978) (see areas 51, 57, 77).
51 57 67
