15

MANAGEMENT OF SHARK FISHERIES IN WESTERN AUSTRALIA¹

C. Simpfendorfer
36 Mcquarie Avenue, Padbury, Western Australia 6025, Australia

1. INTRODUCTION

1.1 Distribution of the fishery

The Western Australian Temperate Shark Fishery (WATSF) extends from the border between Western Australian and South Australia (129°E), west and north to about Steep Point at the southern end of Shark Bay (26° 30'S) (Figure 1). Within this region the fishery stretches from the coast to the edge of Australia's 200 nautical mile Exclusive Economic Zone. The WATSF is actually a combination of two closely relate fisheries, each with it own management plan. The Joint Authority Southern Demersal Gillnet and Demersal Longline Limited Entry Fishery (JASDGDLLEF) covers the south and south-west coasts of Western Australia, while the West Coast Demersal Gillnet and Demersal Longline Interim Managed Fishery (WCDGDLIMF) covers the west coast north of 33°S to 26° 30'S (Figure 1). The JASDGDLLEF is divided into two areas:

1. Zone 1, covering the south-west of Western Australia between 116°30'E and 33°S, and
2. Zone 2, the southern coast east of 116°30'E.

1.2 Species composition of the fishery

Fishers operating in the WATSF target six species (or groups) of sharks - dusky shark (Carcharhinus obscurus), whiskery shark (Furgaleus macki), gummy shark (Mustelus antarcticus), school shark (Galeorhinus galeus), sandbar shark, (Carcharhinus plumbeus, also known locally as the thickskin shark), and spurdogs (Family Squalidae, mostly Centrophorus uyato). The species targeted by fishers is dependent upon the area in which fishing occurs and the time of the year. (see 1.1.1). A number of other shark species are also landed by fishers, but these are not targeted, including spinner shark (Carcharhinus brevipinna), smooth hammerhead shark (Sphyrna zygaena), grey nurse shark (Carcharias taurus) and wobbegong shark (four species - Orectolobus maculatus, O. ornatus, O. sp and Sutorectus tentaculatus) (Table 1). The “other” category used in Table 1 results from the Fisheries Western Australia's Catch and Effort System (CAES) not having codes for rarely caught species. Species that fall into this category include mako shark (Isurus oxyrinchus), white shark (Carcharodon carcharias), bronze whaler shark (Carcharhinus brachyurus) and tiger shark (Galeocerdo cuvier).

¹ There are nominally four shark fisheries in Western Australian waters. Two of these fisheries are in the north of the State and target tropical species of shark such as the Australian blacktip shark (Carcharhinus tilstoni), spot-tail sharks (C. sorrah) and hammerhead sharks (Sphyrna spp.). These fisheries are in reality part of Australia's North Shark Fishery that stretches from Queensland to North West Cape in Western Australia. However, because of jurisdictional arrangements between the State and Commonwealth Governments these two fisheries are managed by Western Australia. The two northern fisheries are not considered in this review.

Western Australia's other two shark fisheries exist in the southern half of the State and target temperate water species. It is these two fisheries that are reviewed here. These fisheries have existed for over fifty years and begun during World War II. Where ever possible in this review published sources of information and data have been used. However, in many instances information has had to be derived from personal experience with the fishery and discussions with managers, researchers, fishers and others, with knowledge of the fishery. This information has been gathered over the four years that I have worked on this fishery.

Figure 1

Boundaries of management areas within the Western Australian Temperate Shark Fishery

1.3 Biology of key species

i. Carcharhinus obscurus

Carcharhinus obscurus is a large species of carcharhinid shark that has a world-wide distribution in tropical, sub-tropical and temperate waters and occurs in all Australian waters (Last and Stevens 1994). In Western Australian waters the young are born in the southwest of the state at 85–100cm in length. The results of a tagging study on recently pupped C. obscurus indicates that they occupy the area between Shark Bay and the central South Australian coast (Simpfendorfer et al. 1996). Most, however, remain in the area from Kalbarri (27°42'S, 114°10'E) to Albany (34°57'S, 117°54'E). It is the youngest age classes that are the target of the fishery with more than 70% of C. obscurus being less than one year of age (Simpfendorfer unpubl. data). On the basis of data from tag recaptures, growth of young juveniles is estimated to be approximately 9cm/yr (Simpfendorfer et al. 1996).

Published age and growth information are only available for C. obscurus populations from the western North Atlantic (Natanson et al. 1995) and the southeast Indian Ocean (Natanson et al. 1996). These data indicate that maturity occurs between 14 and 21 years, and the maximum age is probably in excess of 45 years. Preliminary data from the Western Australian population indicate a similar pattern (Simpfendorfer unpubl. data). There are limited data on the reproduction of C. obscurus. In Western Australia the average litter size is ten (Simpfendorfer unpubl. data), with females not breeding every year. It has recently been suggested that the reproductive periodicity of females in the western North Atlantic is three years (GSAFDF 1996). Mature individuals in Western Australian waters occur off the north-west coast in late winter and spring, but migrate south to the pupping areas in the south-west in late summer and autumn. The maximum reported size is 365cm (Last and Stevens 1994).

ii. Carcharhinus plumbeus

Carcharhinus plumbeus is a moderately large carcharhinid shark that has a world-wide distribution in sub-tropical and warm temperate coastal waters (Last and Stevens 1994). In Australian waters it occurs most commonly in the warmer areas, but reaches as far south as Esperance in southern Western Australia and Coffs Harbour in New South Wales. In Australian waters the young are born at around 60cm, mature around 150cm and grow to 240cm. Females produce litters of between 3 and 8 young every second year (Last and Stevens 1994). Preliminary tagging data from southern Western Australian waters of juvenile C. plumbeus indicate that they move relatively long distances along the west coast (Simpfendorfer et al. 1996).

iii. Furgaleus macki

Furgaleus macki is a triakid shark endemic to southern Australia. It ranges from North West Cape south and east to Bass Straight. It grows to around 150cm in length. Simpfendorfer and Unsworth (in press) have descried the reproductive biology of this species. The young are born at 22 to 27cm; males mature at 121cm and females at 126cm. Mating is probably in August and September and ovulation several months later in February and March. Females produce litters of between 4 and 28 (mean 19) every second year. The gestation period is 7–9 months, with birth from August to October. Age and growth data have not been published, but preliminary data (Simpfendorfer unpubl. data) indicates that they mature at around 5 years of age and live to a maximum of 20 years. The diet is composed almost exclusively of octopus.

Furgaleus macki are caught in commercial quantities throughout the WATSF. The mesh size of the gillnets used in the fishery result in the capture of sub-adult and adult animals (Simpfendorfer et al. 1996). In the eastern section of Zone 2 of the JASDGDLLEF the catch ofF. macki is mostly males while in Zone 1 of the JASDGDLLEF the catch is dominate by females. As smaller juveniles are not caught in the fishery little is known of the biology or distribution of this section of the population.

iv. Galeorhinus galeus

Galeorhinus galeus is a large triakid shark that grows to a maximum size of 175cm in Australian waters (Last and Stevens 1994). It has a number of distinct populations around the world, including southern Australia, New Zealand, west coast of the USA, the southern two thirds of South America, eastern North Atlantic, Mediterranean Sea, and South Africa. Examination of genetic data indicates that these geographically separate populations are different stocks of a single species (Ward and Gardner 1996). The genetic data from southern Australia indicate that only a single stock occurs. Comparison of genetic data between southern Australia and New Zealand indicate significant differences between the stocks. However, tagging in both Australia and New Zealand indicates there is mixing between these areas (J. Stevens, CSIRO, Hobart, pers. comm.).

Within Australian waters, G. galeus is distributed from Fremantle, south and east to Moreton Bay in Queensland (Last and Stevens 1994). However, in Western Australian waters they rarely occur east of 124°E on the south coast, and 85% of the catch is taken to the east of 126°E (Simpfendorfer unpubl. data). G. galeus caught in the WATSF are mainly sub-adults and adults ranging in size from 107–137cm fork length (Simpfendorfer et al. 1996). There is no evidence of smaller juveniles occurring in Western Australian waters. Although caught year-round in Western Australian waters, the biggest catches are taken between September and October.

Galeorhinus galeus is born in nursery areas in southeastern Australia in December and January (Stevens and West 1997). The size at birth is approximately 30cm. Maturity is reached at 120cm in males and 130cm in females (Last and Stevens 1994) which corresponds to an age of about 10 years (Moulton et al. 1992). Growth parameters have been estimated by Moulton et al. (1992), but these are unvalidated. Maximum age is estimated to be in excess of 55 years. Females produce litters of 15 to 43 pups every second or third year (Last and Stevens 1994). There have been substantial amounts of tagging carried out on G. galeus in southern Australia. Tagged animals released in Western Australian waters have been recaptured in Western Australia, South Australia, Victoria and Tasmania (T. Walker, Marine and Freshwater Resources Institute, pers. comm.) indicating that there is a large amount of mixing in the population between the WATSF and the Southern Shark Fishery.

v. Mustelus antarcticus

Mustelus antarcticus is a large species of triakid shark that is endemic to southern Australia (Last and Stevens 1994). Genetic studies have found that there is a single stock along the entire south coast of Australia (MacDonald 1988; Ward and Gardner 1996). Within Western Australian waters commercially signifcant catches are only taken cast of Albany with only occasional catches made in more western or northern areas (Heald 1987; Lenanton et al. 1989). The majority of the M. antarcticus caught in the WATSF range in size from 90 to 130cm fork length (Simpfendorfer et al. 1996).

M. antarcticus are born at 30–36cm, males mature at approximately 93cm and females at approximately 130cm (Lenanton et al. 1990). Age and growth work in southeastern Australian indicates that the age at maturity is reached at 4 years in males and 5 years in females (Moulton et al. 1992). Mating occurs from late October through to early February with parturition 11 to 12 months later. Lenanton et al. (1990) reported litter sizes between 1 and 31 produced every year in Western Australian waters. More recent sampling in Western Australian waters has produced a maximum litter size of 45. The maximum size reached in Western Australian waters by males is 130cm, and for females it is 164cm (Lenanton et al. 1990).

Tagging of M. antarcticus in Western Australian waters since 1994 has demonstrated that only a small proportion of the population move 100km. Most tagged individuals have been recaptured less than 100km from their release point. A number of individuals, however, have moved much further, e.g. to South Australian waters (T. Walker, Marine and Freshwater Resources Institute, pers. comm.).

vi. Family Squalidae

There has been no specific research on the species of the Family Squalidae that are caught in the WATSF. There is no information on species composition, although fishers report that the main species targeted is Centrophorus uyato. As a group, this family normally live on the continental slope, are slow growing and produce small litters. Further research is required to provide an understanding of this component of the WATSF.

1.4 Associated species either as bycatch or discards

Teleost fish make up the only significant bycatch associated with the catch of sharks in the WATSF and comprise approximately 15% of the total catch (by weight). This figure varies considerably by area, with teleosts making up 23% of the catch (by weight) in the WCDGDLIMF, 14% in Zone 1 of the JASDGDLLEF, and 10% in Zone 2 of the JASDGDLLE. The higher level of teleost catch in the West Coast area is largely due to a number of longline fishers who target teleosts rather than catch sharks. These longline fishers, however, are controlled under the management plan for this area, and their catch is attributed to the fishery.

The composition of the teleost catch in the WATSF is given in Table 2. The data for Table 2 are derived from the monthly catch returns provided by fishers. As such they only include information on species that are landed and sold. A much greater diversity of teleost fish is captured than is reflected by the reported figures. The teleost component of the catch is an important component for all fishers in the fishery. Several species of commonly caught teleost fish are discarded, either because they are worthless to fishers, or management plans for other fisheries prohibit their landing. Commonly discarded teleost species include Kyphosus spp., Dactylophora nigricans and Arripus truttaceus. There are no figures available on the proportion of the catch discarded, however, on the basis of several years of observations on WATSF vessels the level is low.

A number of elasmobranchs are discarded by the fishery because there is no market for them. The most common is the Port Jackson shark (Heterodontus portusjacksoni) which is normally discarded alive. However, some fishers kill them because they perceive them as being a nuisance. Other elasmobranchs that are discarded include thresher sharks (Alopias spp.), catsharks (Family Scyliorhinidae), wobbegongs mostly less than two metres in length (Family Orectolobidae), stingarees (Family Urolophidae), and shovelnose rays (Family Rhinobatidae). There is also some discarding of normally retained species that have been heavily damaged by sea lice or leather jackets. Lightly damaged sharks are normally retained.

There is very little bycatch of marine mammals, marine reptiles and sea birds due to the demersal nature of the fishing gear used. Observations by the FWA research staff on commercial fishing vessels indicate that very small numbers of bottlenose dolphins, seals, green turtles and shearwaters are caught. There are no quantitative data available on this bycatch.

1.5 Discussion

The WATSF is a multispecies fishery that operates in the southern half of Western Australia targeting a number of demersal shark stocks. The target species vary from locally endemic (e.g. Furgaleus macki) to circum-global (e.g. Carcharhinus obscurus) shark species. Teleost species are rarely targeted but form an important component of the catch for most fishers.

Varying amounts of biological data are available for all of the main species of sharks caught in the WATSF. Biological studies of sharks in Western Australian waters have until recent years been limited (Simpfendorfer and Donohue in review). Consequently, much of the biological data for species such as C. obscurus, C. plumbeus, G. galeus and M. antarcticus initially came from other parts of their range. Recent research (e.g. Lenanton et al. 1990; Simpfendorfer et al. 1996; Simpfendorfer and Unsworth in press) has begun to provide locally relevant biological data.

There is a high level of utilisation of the catch from the WATSF. The lack of catch quotas means that fishers rarely high-grade, resulting in all marketable product being landed, including damaged carcasses. Markets also exist for almost all shark and teleost species captured. The main exception to this is Heterodontus portusjacksoni which can be common in catches. The hardy nature of this species means that most can be returned to the water alive, however, some fishers persist in killing them before discarding them. Although the fishery mostly employs gillnets there is little bycatch of marine mammals, marine reptiles or sea birds due to the demersal nature of the gear. This contrasts greatly with pelagic nets which can have significant impacts on non-target populations.

2. DEVELOPMENT AND CURRENT STATUS OF MEANS OF PROSECUTING THE FISHERY

2.1 Evolution of the harvest process and fishing fleet

The WATSF originated in the waters of Leschenault Inlet, near Bunbury (33°20'S, 115°34'E) in 1941 when two fishermen began catching gummy sharks (Mustelus antarcticus) with longlines (Whitley 1943; Heald 1987). Over the next year six vessels were catching gummy sharks in the Inlet and the ocean waters around Bunbury. The importance of Leschenault Inlet as a source of gummy shark catches rapidly declined (Whitley 1943) and has not produced significant catches since the first few years of the fishery. In 1943 and 1944 Gilbert Whitley conducted longline fishing trials from the ports of Bunbury, Albany and Esperance. He concluded (Whitley 1943, 1944a,b) that the catches he obtained indicated that stocks in each of these areas were sufficient to support commercial fishing. By the end of the second world war it is believed that commercial shark fishing was taking place in a number of ports in southern Western Australia (Heald 1987).

The use of longlines as the principal catching method for sharks continued at least until the 1960s. Multifilament gillnets were introduced in the late 1950s. Monofilament nets were introduced a few years later in the early 1960s. Some fishers were also catching sharks during the 1950s and 1960s using handlines. Few records were kept of the vessels and gear used until the 1970s so it is difficult to know the contribution of each of these gears to the overall shark catch. However, gillnets were hand-hauled from small vessels, limiting the amount of net individual fishers used to several hundreds of metres.

Heald (1987) produced the first information on the vessels and gear used in the WATSF. He analysed data on the fishery between 1975/76 and 1983/84. In 1975/76 there were 63 gillnet vessels operating, most of which were considered part-time vessels on the basis that they caught less than 5t of shark. Only 9 vessels reported catching more than 10t of shark in 1975/76. In the same year Heald (1987) noted that 32 vessels reported catching shark with longline, and 95 with handlines. Nine years later there were 122 gillnet vessels (just over half catching less than 5t of shark), 49 longline vessels, 152 handline vessels, and 22 dropline vessels, reporting catches of shark. The shark catches of handline and dropline vessels was only a minor component of their catch, with only a handful catching more that one tonne of shark. The number of gillnet vessels catching more than 10t increased to 30 in 1983/84.

Heald (1987) also documented a 240% increase in the length of gillnet used by fishers in the WATSF between 1975/76 and 1983/84. In 1975/76 the average length of gillnet used was 686m. This rose to nearly 1700m by 1983/84. This increase in the amount of net used was largely the result of the introduction of powered net drums, rollers, and net spreaders, which freed fishers from hand-hauling nets and made operating longer nets a viable option. The move to power-hauled gear also enabled fishers to move to larger, purpose-built vessels that could fish in more unfavourable conditions and operate further from port. This, combined with the introduction of echo sounders and radar in many vessels during the same period, must have resulted in a dramatic increase in the efficiency of many fishers. With the introduction of power-hauled gillnets, longlines began to decrease in popularity and by the end of the 1980s few longliners remained. By the mid-1990s there were no full-time shark fisherman using longlines.

After the increases in the number of vessels fishing for shark (both part-time and full-time) in the late 1970s and early 1980s some fishers reported declining catch rates and financial difficulties (Heald 1987). As a result the increase in vessels catching shark stopped. The introduction of a management plan in 1988 for the area south and east of 33°S on the west coast (the JASDGDLLEF see 1.1.1), which included limited entry provisions and effort controls, resulted in a reduction in the number of vessels allowed to fish for sharks using gillnets and longlines. After the plan was introduced there were 42 licences permitted full access to the fishery, while a further 33 received supplementary access (entitling them to use a small amount of hand-hauled longline or gillnet). Fishing effort in Zone 1 of the fishery remained stable after the introduction of the management plan. However, in Zone 2 effort rose sharply as a result of a significant amount of latent effort in the fishery. Changes to the management plan to reduce effort in the 1990s (see Section 4.2.6) meant that fishers needed to acquire more effort units, and as a result the number of full-time vessels operating in both Zones of the fishery had declined to 15 in Zone 1 and 21 in Zone 2. The number of supplementary access fishers using their entitlement each year had decreased only slightly to 31 in 1996.

The area north of 33°S remained outside the JASDGDLLEF management plan when it was introduced in 1988. However, when fishers in this area observed what had occurred in the JASDGDLLEF many decided to increase their effort in the hope of gaining greater access if, or when, limited entry management was introduced. The number of gillnet vessels increased, along with their fishing effort and catch. This resulted in the Fisheries Western Australia capping the number of vessels at 42 in 1991. Further management was not introduced to this fishery until 1997, but fishing effort decreased considerably after 1988/89. During the 1990s less than half of the fishers with entitlements to use power-hauled gear north of 33°S did so. With the implementation of the management plan currently underway (WCDGDLIMF - see 1.1.1 above) it is expected that there will be a further decrease in the number of vessels using gillnets and longlines to catch sharks in this area.

The form of the gillnets used by fishers to catch sharks in the WATSF result from a combination of provisions of the management plans, and functionality. Those specifications controlled by the management plans are:

1. Gillnets must be demersal (i.e. in contact the sea floor).

2. Minimum mesh size of 16.5 cm in Zone 1 of the JASDGDLLEF, and 17.8cm in Zone 2 of the JASDGDLLEF and WCDGDLIMF.

3. Mesh depth of 15 meshes in Zone 2 of the JASDGDLLEF, 15 or 20 meshes in Zone 1 of the JASDGDLLEF (effort units must be surrendered to move from 15 to 20 mesh depth), and 20 meshes in the WCDGDLIMF.

Although no maximum mesh size is specified in the management plans, all use 17.8cm mesh, except for a small number of fishers in Zone 1 of the JASDGDLLEF who use 16.5 cm mesh. Fishers have found by experience that this mesh size gives them the best combined catches of gummy, whiskery and dusky sharks. The net strength used is either line 30 or line 35 monofilament. The hanging ratio is not specified by the management plans, but most fishers usually use between 0.5 and 0.6. Nets range in length from around 600m for supplementary access holders to 7000m, with most in the range from 3000m to 5000m. The maximum net length a fisher is permitted to use depends on the number of effort units held (see Section 4.2.6). The nets are held on hydraulic net reels, normally mounted toward the stern on the forward-wheelhouse vessels typical of the fishery.

There are two styles of fishing employed in the fishery:

1. Extended trips that last from 3 to 14 days. These vessels have refrigerated holds and operate large distances from their home port. These vessels are the largest in the fleet. Set times for gillnets are short, typically 3 to 8 hours, with the gear being worked around the clock. This style of fishing is carried out by practically all fishers in Zone 2 of the JASDGLLEF, but very few fishers in the other areas.

2. Day trips. Fishers operating in this manner return to port each day after clearing and moving their net(s). The nets remain set overnight, with set times ranging from 15 to 24 hours. The vessels rarely have refrigeration. This style of fishing is typical of Zone 1 of the JASDGDLLEF and WCDGDLIMF fishers.

2.2 Evolution of the catch

The first catch figures for the WATSF were collected in 1949, when a catch of 171t of sharks was reported (Heald 1987). The next available data are for 1951, when the Fisheries Western Australia (FWA) commenced a catch recording system. The FWA catch records were collected until 1961 when the Australian Bureau of Statistics (ABS) took over catch recording. The ABS data was collected by fiscal year (July to June), while the early the FWA data was recorded by calendar year (January to December). The ABS stopped collecting catch records in 1975, at which time the FWA assumed responsibility for collecting catch and effort data. Catch data was initially recorded only as “shark”, with no information on the species composition of the catch available. Species specific catch records are available from 1975/76 onwards, although some of the minor shark species were grouped as “other shark”. More species were removed from the “other shark” category in 1988 and recorded separately (e.g. Galeorhinus galeus and Carcharhinus plumbeus).

i. Total shark catch

Total annual shark catch since 1951 is shown in Figure 2. The catch in 1951 was approximately 50t, significantly less than the 171t reported for 1949 by Heald (1987). Because of the limited knowledge of the fishery from this period it is not possible to determine what resulted in this fall. However, it was at about this time that synthetic vitamin A became available reducing the market for shark livers which had been the major source of this product. Catches in the fishery gradually increased through the 1950s and 1960s, peaking at 441t in 1965/66, and falling slightly at the end of the 1960s. In the early 1970s catches started to increase more rapidly, reaching 646t in 1972/73. However, in 1972 serious concerns about mercury in seafood products became widely publicised. As a result there was a sharp decline in the demand for shark flesh, and landings declined to 350t in 1973/74. Research on the mercury content of Western Australian sharks ensued (Hancock et al. 1977; Caputi et al. 1979). In 1974, on the basis of the results of this research, the Health Department of Western Australia introduced a ban on selling any shark whose carcass weighed more than 18kg (headed, gutted and fins removed) for human consumption. This regulation, and a better understanding of the problems associated with mercury, helped the shark fishery to quickly cover.

Figure 2

Total shark catch (live weight) of the Western Australia Temperate Shark Fishery. Open circles denote data collected by Fisheries Western Australia by calendar year; closed circles represent fiscal year data collected by the Australian Bureau of Statistics and the FWA. Data from Simpfendorfer and Donohue (in review)

The period from the mid-1970s to the late 1980s saw a dramatic increase in the shark catch. This increase was the result of increased fishing, and fishing efficiency, that resulted from the introduction of power-hauled gear and restrictions on other fisheries in which fishers had traditionally worked (e.g. southern blue fin tuna and Australian salmon) (see Section 2.1). From just under 500t in 1975/76 the catch rose steadily to over 1500t in 1984/85, and 2200t in 1987/88. After the introduction of the management plan for the JASDGDLLEF in 1988, and restrictions on power hauled gear north of 33°S, catches stabilized at around 1900t from 1989/90 until 1992/93. Catches subsequently declined and in 1996/97 were 1376t.

ii. Furgaleus macki

The annual catch of F. macki in the WATSF from 1975/76 onwards is shown in Figure 3. The catch of F. macki increased during the late 1970s and early 1980s, from 162t in 1975/76 to 611t in 1981/82. Initially this increase was the result of increasing catches in Zone 2 of the JASDGDLLEF, but between 1979/80 and 1981/82 the catch in Zone 1 of the JASDGDLLEF increased from under 100t to over 300t (Figure 3). Total F. macki catch remained between 400t and 500t between 1982/83 and 1991/92. However, during this time the Zone 1 catch declined while the Zone 2 catch increased (Figure 3). Since 1992/93 the total F. macki catch has declined and in 1996/97 was 217t. The decrease in the mid-1990s was largely a result of the delcining catch in Zone 2.

Figure 3

Annual catches of Furgaleus macki in the Western Australian Temperate Shark Fishery. - total WATSF; • - Zone 1 JASDGDLLEF; ■ - Zone 2 JASDGDLLEF; ▲ - WCDGDLIMF.
Data from Fisheries Western Australia

iii. Mustelus antarcticus

Annual catches of M. antarcticus in the WATSF are shown in Figure 4. Catches of M. antarcticus in the WCDGDLIMF and Zone 1 of the JASDGDLLEF are negligible. Catches in Zone 2 of the JASDGDLLEF were 64t in 1975/76, and increased steadily up to 223t in 1981/82. Catches remained between 150 and 200t until 1986/87, at which point catches again began to rise. The catch reached 538t in 1991/92, and 498t in 1992/93. In 1993/94 the catch fell by about half, to 263t. Fishers attributed the decline in the catch to unusual behaviour of the stock with traditional fishing grounds producing poor catches. The catch has remained low since that time, but in the years after 1993/94 effort reductions of 30% under the JASDGDLLEF management plan account for much of the reduced catch. The catch of M. antarcticus in 1996/97 was 311t.

iv. Carcharhinus obscurus

Annual catches of C. obscurus in the WATSF are shown in Figure 5. The catch in 1975/76 was 128t and this increased steadily to 354t in 1982/83. In the two years after 1982/83 catches rose to over 700t (Figure 5) as F. macki became more difficult to catch. Catches remained high during the mid and late 1980s, as first Zone 1 and then the WCDGDLIMF went through periods of peak catches of around 300t. Since 1990/91 catches of C. obscurus have remained between 480 and 580t, with each management area having similar catches.

2.3 Evolution of the fishing effort

Data on fishing effort for the WATSF were not collected until 1975/76. Subsequently, fishers have been required to report monthly on the number of days fished, length of net or number of hooks set, number of sets/day, and areas fished. The effort unit used for the fishery is kilometre hours of gillnetting (km.gn.hr). Heald (1987) described the method by which non-gillnetting effort is converted to gillnet effort.

Figure 4

Annual catches (live weight) of Mustelus antarcticus in the Western Australian Temperate Shark Fishery (Catch figures are only for Zone 2 of the JASDGDLLEF as catches in other areas a minimal). Data from Fisheries Western Australia

Figure 5

Annual catches (live weight) of Carcharhinus obscurus in the Western Australian Temperate Shark Fishery. - total WATSF; • - Zone 1 JASDGDLLEF; ■ - Zone 2 JASDGDLLEF; ▲ - WCDGDLIMF. Data from Fisheries Western Australia

Total fishing effort, and the effort by management area, for the WATSF is shown in Figure 6. Total fishing effort rose steadily from 64 691km.gn.hr in 1975/76 to 295 477 1983/84. Effort rose in the mid-1980s, reaching 786 687km.gn.hr in 1987/88. The increases during the period from 1975/76 to 1986/87 were the result of similar increases in effort in each of the management areas. However, in 1987/88 and 1988/89 the effort in the area north of 33°S doubled as a result of speculation about future management of the fishery (see Section 2.1). At the same time effort in Zone 1 of the JASDGDLLEF decreased to approximately 75 706 km.gn.hr, a level at which it has remained relatively constant since. Effort north of 33°S fell just as quickly as it rose remaining around 150 000km.gn.hr during the 1990s. Total fishing effort has been falling since 1987/88, reaching 327 306km.gn.hr in 1996/97.

Figure 6

Annual fishing effort in the Western Australian Temperate Shark Fishery. - total WATSF; • - Zone 1 JASDGDLLEF; ■ - Zone 2 JASDGDLLEF; ▲ - WCDGDLIMF Data from Fisheries Western Australia

2.4 Markets

2.4.1 Introduction

The primary use of sharks caught in the WATSF is for human consumption. Shark is particularly popular in “fish'n'chips” and much of the product is used in this industry. The majority of the flesh is sold in markets in Perth (Western Australia's capital city). Some fishers sell directly to fish shops, or fish processors, in their local area or in Perth. Others send their product to a fish market in Perth that has daily auctions. The majority of M. antarcticus and G. galeus caught by fishers in Zone 2 of the JASDGDLLEF is sent by refrigerated road transport to markets in eastern Australia. There are occasional exports of flesh to Europe, but these are rare.

The only group of species that are not caught primarily for their flesh are the deepwater squalids (e.g. Centrophorus uyato). This group of sharks is caught for their liver oil which has a high squalene content. There are only a couple of boats that target squalids. The livers are stored in drums on board the vessel and processed ashore for the crude oil. The oil is sold to companies in other Australian states and is normally exported. The flesh from squalids has a mercury content several times greater than the legal maximum value for shark which makes selling the flesh difficult. Some is sold as pet food, and some is exported, but most is simply dumped once the liver has been removed.

Fishers remove the fins from almost all of the sharks that they catch as part of onboard processing. The fins are sold frozen to buyers who normally export them directly to South-East Asia. With most of the sharks caught in the fishery being relatively small the prices received are well below that paid for large fins. There is limited utilisation of other products from sharks caught in the WATSF. Skins are not normally used, although a small tannery exists in Esperance for shark and fish skins. There is little or no removal of cartilage by fishers to supply the shark cartilage trade. The livers of non-squalid sharks are discarded.

2.4.2 Revenues from the fishery

Information on the value of the fishery was derived from annual reports on fisheries statistics produced by the Australian Bureau of Statistics and the Australian Bureau of Agricultural and Resource Economics. These figures give production values for all shark caught in Western Australia. The figures therefore include the small catches in the northern half of the State. However catches in this area are small and will have only minor impact on the figures. The figures also do not include the value of the scalefish caught by the fishers, nor do they include the value of shark fins. As a result the actual value of these fisheries is greater than that suggested by the figures.

For much of the history of the WATSF the value of the catch has been relatively minor (Figure 7). However, as the production from the fishery rose rapidly in the 1980s the value also increased. This increase in value was not only the result of increased catches, but also improved market prices due to factors such as reliable supply, improved product handling and access to markets. Since the rapid rise in value during the 1980s the WATSF has normally had a production value of between A$6 and 7 million (Figure 7).

Figure 7

Value of the sharks caught in all Western Australian waters. Values are based on prices received by fishers for their product. Data from Australian Bureau of Statistics Annual Western Australian Fisheries Statistics (1966/67 to 1989/90) and the Australian Bureau of Agricultural and Resource Economics Australian Fisheries Statistics (1990/91 onwards)

2.5 Economics of the fishery

There has never been an economic survey of the WATSF to estimate harvest costs, profitability, or other economic statistics. Donohue (1994) used a bioeconomic model to examine future management options for the fishery. He recommended that effort be reduced in the fishery or else there would be a dissipation of resource rents and a lowering of licence values.

At present there is a nett movement of fishers out of the WATSF. Some fishers currently have their licences on the market, but there are few people interested in entering the industry. The recent reductions in effort under the management plans for the JASDGDLLEF and the WCDGDLIMF has forced the industry to restructure, with fishers staying in the industry needing to purchase effort units to maintain their level of fishing. This has permitted fishers leaving the industry to sell, or lease, their effort units. However, they have not been able to sell their limited entry licence because no new operators are entering the fishery.

The WATSF receives no government subsidies other than a proportion of the costs associated with managing the fishery. The fishery generates income for the Australian government through taxation on profits, and income for the Western Australian government through licence fees.

2.6 The fisheries work force

The majority of fishers that currently operate in the WATSF do so on a full-time basis. Most vessels work with two or three crew, including a skipper. Many of the skippers are owner-operators, while a few licences employ skippers to operate their vessel. Crew are normally employed on a share-fishing basis, with wages derived from a proportion of the income and expense.

3. MANAGEMENT OBJECTIVES

3.1 The fisheries within the context of national and Western Australian fisheries policies

The WATSF is managed under the Fish Resources Management Act 1994, which has a number of specified objectives in relation to fisheries:

• to conserve fish and protect their environment

• to ensure that the exploitation of fish resources is carried out in a sustainable manner

• to enable the management of fishing, aquaculture and associated industries and aquatic eco-tourism

• to foster the development of commercial and recreational fishing and aquaculture

• to achieve the optimum economic, social and other benefits from the use of fish resources

• to enable the allocation of fish resources between users of those resources and

• to provide for the control of foreign interests in fishing, aquaculture and associated industries.

3.2 Objectives for the management of the Western Australian temperate shark fishery

The Western Australian Demersal Gillnet and Demersal Longline Fishery Management Advisory Committee (WADGDLFMAC) is the body that provides advice on the management of the WATSF to the Western Australian Minister of Fisheries. The Minister has ultimate responsibility for the management of Western Australia's fisheries (Section 4.1). After the formation of the WADGDLFMAC in 1995 a number of strategic planning sessions were held to develop a mission statement and a set of objectives for the management of the WATSF.

The mission statement adopted by the WADGDLFMAC was:

“To effectively and efficiently manage the allocation, conservation and development of shark stocks in Western Australia for future and present generations.”

The objectives adopted were:

“To restore, or maintain, the biomass of whiskery and gummy sharks at or above 40% of the original biomass by 2010.

To restore or maintain the biomass of dusky whaler sharks at or above 40% of the original biomass at 2040.

To ensure decisions are as equitable as possible across all users of Western Australia's shark stocks when and where adjustments in exploitation are considered necessary.

To provide long term economic viability for commercial users of the resource.

To provide a transparent, flexible management structure that is responsive to industry needs.”

3.3 Discussion

There is a very clear set of objectives for the management of the WATSF. These objectives were developed by the WADGDLMAC, a committee composed mostly of shark fishers (see Section 3.1). The objectives provide specific targets for the management of the main commercial shark species as well as guiding principles for the management of the fishery in terms of economics, equity and structure.

The objectives provide a valuable tool for the WADGDLMAC in formulating and assessing recommendations on the future management of the WATSF. Prior to the objectives being adopted the WADGDLMAC often found it difficult to make recommendations that were consistent with the advice that it received, particularly in relation to the status of the stocks. This is understandable in some respects because the fishers who sat on the committee were asked to make decisions regarding the future of the fishery that may have resulted in them, or their colleagues, facing economic hardship. However, with the objectives now in place, the decision making process is much more focused and produces recommendations consistent with the advice presented to it.

4. MANAGEMENT POLICIES AND THE POLICY SETTING PROCESS

4.1 Identification and evaluation of policies

Management arrangements, and the legislation under which they are governed, differ for the two fisheries (JASDGDLLEF and WCDGDLIMF). The JASDGDLLEF is a Joint Authority Fishery (JAF). A JAF is one that involves both the Western Australian Government and the Commonwealth Government (Australian). The JASDGDLLEF is a JAF because two of the major species (Mustelus antarcticus and Galeorhinus galeus) comprise shared stocks with the Southern Shark Fishery which is managed by the Commonwealth. The arrangements of a JAF are regulated by the Fish Resources Management Act 1994 Act (State) and the Fisheries Management Act 1991 (Commonwealth). The day-to-day management of the fishery is vested in Fisheries Western Australia, but major changes to the management require the approval of both JAF partners (specified as the two relevant Ministers under the Acts). In the situation were there is a dispute between the JAF partners the Commonwealth legislation will take precedence. The WCDGDLIMF is managed solely by Fisheries Western Australia.

When the FWA undertook to introduce management into what was to become the JASDGDLLEF and the WCDGDLIMF it set up industry-based working groups to make recommendations in terms of the management of the fisheries. Prior to these groups being formed there was little or no management policy for the WATSF and decisions were made by the FWA and the Minister of Fisheries. The working groups comprised a number of fishers from the appropriate area and members of the FWA. They examined information on the status of the resources and past and present levels of fishing effort. The working groups developed mechanisms for allocating access to the fishery and made recommendations about permitted gear and fishing practices. The recommendations from the working groups (Millington 1986, Hall 1993) were formally adopted by the Minister of Fisheries, and formed the basis for the management plans for these fisheries.

When management was introduced into the JASDGDLLEF, the Minister of Fisheries formed the Southern Demersal Gillnet and Demersal Longline Fishery Management Advisory Committee (SDGDLFMAC). This committee made recommendations to the Minister on issues relating to the fishery. The Committee comprised four full access JASDGDLLEF fishers, one supplementary JASDGDLLEF fisher, and a recreational fisher. The committee was chaired by a member of the FWA. Research officer(s) from the FWA with expertise in shark fisheries, the Western Australian Fishing Industry Council (WAFIC), a fisher from the area that was to become the WCDGDLIMF, and a member of the Australian Fisheries Management Authority (AFMA) had observer status on the committee. Observers freely participate in meetings but do not have voting rights.

In 1995 the SDGDLFMAC was replaced by the WADGDLFMAC to represent both the JASDGDLLEF and the WCDGDLIMF. This committee has five full-time WATSF fishers (2 from Zone 1 of the JASDGDLLEF, two from Zone 2 of the JASDGDLLEF, and one from the WCDGDLIMF), a supplementary JASDGDLLEF fisher, a community/recreational fishing representative, and a member of the FWA. The same observers are present at meetings that were present at the SDGDLFMAC. The Minister of Fisheries retains sole responsibility for management decisions in the fisheries (except for some matters under the Joint Authority JASDGDLLEF, see above) and is free to ignore the advice from the Committee. The relations between the participants in the management process are shown in Figure 8.

Figure 8

Relationship between parties involved in the management process for the Western Australian Shark Fishery. FDWA - Fisheries Western Australia (From Simpfendorfer and Donohue in review)

The WADGDLFMAC meets several times each year to consider resource assessment advice, future management options and management policies. The group recently developed a new Management Plan for the JASDGDLLEF that introduced a five year planning horizon so that decisions regarding the level of fishiny effort and gear regulations are set for five years. Towards the end of the five year period the status of the fishery and the stocks are assessed in detail and a new five year plan developed. The WADGDLFMAC hopes that this five year plan will provide a basis for fishers to better plan their business. Previously, decisions about future management of the fishery were made each year, often only weeks before the start of the new fishing year on 1 June. It is also anticipated that the five year plan will reduce the number of times that the committee has to meet.

4.2 Policies adopted

4.2.1 Resource access

Joint Authority Southern Demersal Gillnet and Demersal Longline Limited Entry Fishery: Prior to the introduction of the management plan for the JASDGDLLEF in 1988 the only restriction on the catching of sharks in Western Australian waters was a valid fishing licence and a restriction on sharks over 18kg for human consumption (see Section 2.1). Vessels that fished in Commonwealth waters prior to 1988 required a Commonwealth fishing licence. On June 1st 1988 limited entry was declared for the area south and east of 33°S for demersal gillnet and demersal longline fishing (the two methods used to catch sharks). To operate either of these fishing gears a fisher required a valid JASDGDLLEF licence. Fishers catching sharks using other methods (e.g. handlines or droplines) were not effected by the management plan. Each JASDGDLLEF licencee is only permitted to operate in the management zone in which he has a fishing history.

Two categories of licence exist in the fishery:

• Full access. These licences are the normal licence for the fishery and are fully transferable.

• Supplementary access. These licences were issued to small operators that did not qualify for full access licences, but who had a historical reliance on the fishery. These licences have restricted access to the fishery (small amount of effort) and are only transferable as part of a total licence package (i.e. when a fisher sells his entire fishing operation).

West Coast Demersal Gillnet and Demersal Longline Interim Managed Fishery: The area north of 33°S remained open access when the JASDGDLLEF management plan was introduced. However, increasing fishing effort (see Section 2.3) resulted in a need to implement a management plan for this area. To cap the rapidly increasing effort while a management plan was developed, the FWA restricted the used of power-hauled gear (essential for commercial shark fishing) in 1991 to those operators already using the gear. This restriction resulted in 42 fishers initially having access to the fishery. These fishers had no restriction on the amount of gear that they could use or how often it was used. The management plan for the fishery was finally implemented in 1997 making entry into the fishery limited. There are no supplementary licences in this fishery and all licences are fully transferable.

4.2.2 Closed areas

There are no closed areas in the JASDGDLLEF. In the WCDGDLIMF the areas around the Abrolhos Isands (28°55'S, 113°50'E) is closed to gillnet and longline fishing. A large area of the coastline directly to the north of the WCDGDLIMF is also closed to shark fishing. This closure covers over 450km of coast line, including Shark Bay and Ningaloo Reef. This closure was introduced in 1989 to protect breeding stocks of C. obscurus and C. plumbeus.

4.2.3 Gear restrictions

Southern Demersal Gillnet and Demersal Longline Limited Entry Fishery: The management plan covers demersal gillnet and demersal longlines. For the purposes of the plan demersal means “wholly or partially in continuous or intermittent contact with the seabed”. Gear specifications under the management plan for gillnets include:

• minimum mesh size of 175mm for Zone 2 and 162.5mm for Zone 1
• maximum net depth of 15 meshes in Zone 2 and 20 meshes in Zone 1 and
• Zone 1 fishers wishing to change from 15 to 20 mesh drop must surrender 20% of their effort entitlement.

There are no specifications for longline gear in the management plan.

The management plan also specified that when in use gillnet or longlines must be hauled at least once each day and that an individual fisher may not use both longline and gillnet at the same time. The maximum length of gillnet, or number of hooks on a longline, is dependant upon a fishers effort entitlement for a particular month.

West Coast Demersal Gillnet and Demersal Longline Interim Managed Fishery: The management plan covers the use of demersal gillnet and demersal longlines as defined for the JASDGDLLEF. Specifications of gillnet gear under the management plan include:

• minimum mesh size 175 mm; and
• maximum net depth of 20 meshes.

There are no specifications related to longlines in the management plan. The maximum length of gillnet, or number of hooks on a longline, is dependent upon a fishers effort entitlement for a particular month.

4.2.4 Vessel regulations

There are no specific regulations in relation to vessels in the management plan. However, all commercial fishing vessels must regularly pass a maritime survey to operate.

4.2.5 Biological regulations

There are no size limits in the management plan in relation to any species of the shark caught. However, the Health Department of Western Australia has a regulation that specifies that no shark with a cleaned weight (head, gut, and fins removed) greater than 18kg can be sold for human consumption because of the mercury content of sharks caught in the fishery. Two species of sharks are protected in Western Australian waters - the whale shark Rhincodon typus and the white shark Carcharodon carcharias. R. typus is never captured in the WATSF, but C. carcharias is occasionally captured.

4.2.6 Effort allocation

The JASDGDLLEF and WCDGDLIMF are input controlled fisheries. The level of fishing effort that each vessel is entitled to use is controlled by a system of time/gear units. At the introduction of each of the fisheries all fishers that met the required conditions to receive a licence were allocated a number of time/gear units. In the JASDGDLLEF the initial allocation was based on the number of months and length of gear used during the period from 1982 to 1985. In the WCDGDLIMF the initial allocation was based on catch history from July 1988 to June 1991. Each time/gear unit entitles a fisher to use a specified length of net for a period of one calendar month. The length of net associated with a unit is different in each of the management areas:

• Zone 1 of the JASDGDLLEF - 540m
• Zone 2 of the JASDGDLLEF - 380m
• WCDGDLIMF - 540m.

The initial length of net associated with a time/gear unit in the JASDGDLLEF was 600m. However, in 1992 concerns over the sustainability of the resources and latent effort resulted in a 10% reduction in the size of a unit to 540m and in 1994 further concerns over the sustainability of the resources resulted in further reductions. In Zone 2 of the JASDGDLLEF this was achieved by a 30% reduction in the length of a unit to 380m, while in Zone 1 there was a 20% suspension of units. The reductions in unit length in the JASDGDLLEF currently only apply to full access licences, with the unit length of supplementary licences remaining at 600m. With time/gear units only currently being introduced to the WCDGDLIMF there have been no changes in the length of a unit. However, the initial allocation of units in this fishery is estimated to result in a reduction of effort of up to 50%.

The number of time/gear units allocated in the JASDGDLLEF was around 2600, composed of:

• 1057 full access units in Zone 1
• 78 supplementary access units in Zone 1
• 1300 full access units in Zone 2
• 166 supplementary access units in Zone 2.

It is anticipated that 675 time/gear units will be allocated in the WCDGDLIMF. Full access time/gear units (including all WCDGDLIMF units) are freely tradable between full access licence holders in the respective fisheries and zone. Units cannot be traded between fisheries (WCDGDLIMF and JASDGDLLEF) or zones.

4.3 Perspectives on management

4.3.1 Managers perspective

Information on the perspectives of the fishery managers on management of the WATSF was derived from discussion with Fisheries Western Australia's Management Officer responsible for shark fisheries. He raised a number of issues:

• The Management Advisory Committee approach to management of the WATSF can result in a slow decision making process. This can be a source of frustration for fishery managers because it appears that decisions are being delayed. However, by including the commercial operators in the management planning process gives a much greater acceptance of the decisions. This leads to a much higher level of compliance to, and understanding of, new management arrangements.

• One improved area of the management process is the linkage between the recommendations from the WADGDLFMAC and the implementation of new management arrangements. At present once recommendations are made they go to the Minister of Fisheries for his consideration and approval (or rejection, or modification). If the recommendations are approved they are drafted into new regulations and published. What would be good is if the WADGDLFMAC could receive draft regulations to ensure that they meet the spirit and intent of the recommendations that it made. The disadvantage of this approach is that it adds extra time to what is an already a lengthy and slow process. The increase in the time would make it more difficult to make timely management decisions.

• The direction that the management of the WATSF is taking is a pleasing one in that the five year plan for the fishery provides greater ability of fishers to plan their operation and make financial decisions. It also should allow the WADGDLFMAC to spend less time each year debating the need for effort reductions, and instead consider other matters such as economics and gear innovation. There is also less need for meetings and this reduces management costs.

4.3.2 Users perspective

The views of the users are based on many discussions with shark fishers (individual fishers asked not to be identified). Fishers raised a number of issues in regard to the management of the fishery:

• Prior to moving to the new five year planning approach, where effort levels are set for five years, fishers were often informed of changes to their level of access to the fishery only a matter of weeks before the start of a new season. This resulted in fishers being unable to plan with any certainty. Fishers had responded very favourably to the new five-year plan approach because of the ability to better plan their business.

• Some fishers considered that there was no need for effort reductions, despite the advice available on the status of the resources. Many fishers considered that when effort reductions were made it was better to have one large reduction that to have several small reductions.

• There was a fair degree of tension between fishers in the WCDGDLIMF and Zone 1 fishers in the JASDGDLLEF. The Zone 1 fishers found it difficult to accept the need for significant effort reductions when the management plan for the WCDGDLIMF was delayed several years allowing fishers there to fish in an unregulated manner, even though they shared stocks. Tension also exists over the management of the boundary between these two areas, with some Zone 1 fishers allowed to fish in the WCDGDLIMF.

• The restriction to trading time/gear units between limited entry licence holders limits the market for units. This became even more limited as some fishers left the industry and the number of licences fell. Fishers have suggested that they would like to see a system where any person can own time/gear units, but where a minimum holding is required to operate in the fishery.

• There was a mixed response to the supplementary fishers from the full access licenses. Some considered that the catch by this sector was so small that it was of no significance, while others wanted to see supplementary licences eliminated.

• The involvement of the fishing industry in the decision making process for the fishery is appreciated by most fishers as they have a forum in which they can express their views, and have their experience and knowledge incorporated into management. However, there is also the feeling that the agenda for the WADGDLMAC is driven by Fisheries Western Australia or the Minister of Fisheries.

4.4 Discussion

Australian shark fisheries are among the most strictly managed and regulated in the world. The WATSF is no exception with a complex management structure and strict regulation of fishing effort and fishing gear. Given the susceptibility of shark populations to overfishing (Holden 1974, Stevens et al. 1997) the high degree of regulation and management in the WATSF provides an important framework for ensuring the sustainability of the fishery. In most targeted shark fisheries, where there has been little or no regulation and management, stocks have collapsed and fisheries closed (Stevens et al. 1997).

The management structure of the WATSF is based on a high degree of industry consultation and representation. The consultative process increases the amount of time that decisions take to be made and changes implemented. However, decisions have much greater support from the fishermen, a factor important in a fishery that relies to a certain degree on self-regulation. It has also been possible for some sectors to delay or derail the implementation of necessary management changes because of the complex system. The ability to cause such delays or derailments has been significantly reduced since the adoption of the management objectives (see Section 3).

Although the involvement of resources users in the management process has mostly worked well, there have been times when this was not so. When recommendations about the future management of the fishery require a significant reduction in the allowable fishing effort the WADGDLFMAC finds it difficult to make a decision. This is because the fishers on the committee are required to make a decision that will have a major impact on their future economic viability or that of their colleagues. In situations such as this, the FWA, or the Minister of Fisheries, have had to apply significant pressure on the WADGDLFMAC for suitable recommendations to be made. In the event that the MAC refuses to make any recommendations it is likely that the Minister of Fisheries decides based on the recommendations of the FWA without input from the WADGDLFMAC.

The current regulations in the WATSF are typical of those in input controlled fisheries. There are controls on the amount of fishing effort and on the gear used. The core of the effort control system are the time/gear units, which are the effort equivalent of ITQs. The use of monthly time units allows fishers to tailor their fishing operation to temporal changes in shark abundance, maintenance requirements of their vessel, operations in other fisheries, holidays, etc. It also allows for part-time operators to exist in the fishery without the need to invest in a full-time operation.

5. RESOURCE ASSESSMENT

5.1 Provision of resource assessment advice

Advice on the status of the shark resources fished by the WATSF is provided by the Fisheries Research Division of Fisheries Western Australia. This advice is presented to the WADGDLFMAC as part of its considerations of future management of the WATSF. Written stock assessment advice for the shark stocks has been provided annually since 1993 (Simpfendorfer et al. 1993, 1995, 1995b, 1997). At least one member of the Fisheries Research Division with expertise in shark fisheries is present at WADGDLFMAC meetings to act as an advisor on scientific issues (including resource status).

5.2 Fisheries statistics

5.2.1 Methods used for collection of catch and effort data

All licenced commercial fishers in Western Australia are required by legislation to supply catch and effort data to the FWA. Catch and effort data is supplied monthly and by one degree geographical blocks. Information supplied includes:

• fishing method
• number of days fished in each one degree block
• amount of gear used (net length, number of hooks, etc.)
• number of times the gear is set/day
• number of hours the gear is fishing
• weight of each species by method and block
• landing condition of each species (trunks, fillets, whole, etc.).

These data are processed by the FWA and stored ina computerised system known as the Catch and Effort Statistics System (CAES). The database is used as the source of catch and effort data for the WATSF. Annual figures are produced using an algorithm that corrects for missing information, splits unidentified catches into their components and converts non-gillnet effort into gillnet equivalent effort (Donohue 1993, Simpfendorfer et al. 1997).

The FWA also runs a voluntary logbook system for the WATSF that records catch and effort on much finer spatial and temporal scales. The logbook records data on the number of each species caught by set, exact latitude and longitude of sets; depth of sets, and average weights of species by trip. The data from the voluntary logbook project are stored in computerised form and are used to provide a comparison to the CAES data, and provide information on question that require finer detail.

5.2.2 Evaluation of the data collection process

The collection of the monthly statutory fishing data has been strictly enforced since 1989/90. However, prior to this, there was a degree of non-compliance with the reporting system (Simpfendorfer et al. 1997). Catch and effort figures for the WATSF prior to 1989/90 are corrected for these discrepancies. There is much greater non-compliance with the voluntary logbook project Historically, levels of participation in this project have varied. At times when fishers are seeking to gain access to fisheries participation levels have been high. However, in more recent years, with access to fisheries capped, and with many fisher disgruntled with the level of effort reductions introduced into the fishery, participation in the project has declined substantially (Simpfendorfer et al. 1996). As a result the analysis of fine scale data from recent years has been difficult or impossible. To overcome this problem it would be useful to change the scale at which the compulsory catch and effort data is collected. For example, in the Southern Shark Fishery in south-eastern Australia, the compulsory system records catch on a shot-by-shot basis (D. Johnson, Australian Fisheries Management Authority, pers. comm.). The introduction of a compulsory shot-by-shot catch and effort system would require fishers to maintain more detailed records on board their vessels, something many already do for personal records.

The accuracy of the catch and effort figures for the WATSF relies on the provision of accurate data by fishers. It has been suggested that some fishers do not provide accurate information. However, there has been no documented proof of this occurring with fishers in the WATSF. Simpfendorfer et al. (1996) compared catches from an onboard monitoring programme and the monthly catch and effort data, but was unable to make any conclusions about the accuracy of the data because of restricted observer coverage in some areas and biases in the periods observed. If there were to be mis-reporting of catch and effort data, then it would have an impact on the accuracy of the assessment of the fishery.

5.2.3 Data processing, storage and accessibility

The compulsory catch and effort data are stored on a custom designed database written in Natural Adibas and run on a Unix workstation. The database manages data entry, data storage, reporting, data extraction, and some simple data analysis. Most analysis and reporting of the data is undertaken using SAS. The database also stores the FWA's licensing information. The catch and effort database is accessible to authorized the FWA staff over the Agencies' internal network. The data are confidential and can only be used by authorised staff. The release of specific vessel information can only be done with the licence owners written approval. Data are most commonly released as summaries for groups of vessels (e.g. by management zone in the WATSF). Grouped data can only be released where it has been supplied by five or more vessels.

5.3 Stock assessment

Stock assessment of three key shark species (Furgaleus macki, Mustelus antarcticus and Carcharhinus obscurus) exploited by the WATSF is undertaken by the FWA. Assessment of the status of Galeorhinus galeus, a species that occurs across southern Australian as a single stock, is undertaken as part of the Southern Shark Fishery by the Southern Shark Fisheries Assessment Group. The assessment of G. galeus will not be described here as it forms part of the review of the Southern Shark Fishery (see Walker, this volume). Assessments are not undertaken for the other two key commercial species or groups - Carcharhinus plumbeus and the Family Squalidae.

Catch and effort figures for F. macki, M. antarcticus and C. obscurus have been collected since 1975, but stock assessment work was not commenced until the mid 1980s. Initial assessments took the form of simple examination of crude catch rates (K. Donohue, FWA, pers. comm.). Through time the sophistication of the assessments increased. Algorithms were developed to determine average annual catch rates to better account for changing fishing patterns and technology. Deterministic age-structured population models were developed (e.g. Simpfendorfer et al. 1993, 1995a, b), and these were replaced by stochastic models and risk assessments (Simpfendorfer et al. 1997). In recent years the FWA has moved away from using the age-structured model approach for C. obscurus because of concerns over the validity of such assessment (see below).

5.3.1 Measures of stock abundance

i. Furgaleus macki and Mustelus antarcticus

Stock abundance of F. macki and M. antarcticus is measured by CPUE information derived from the compulsory monthly catch and effort data collected by the FWA. For the purposes of stock assessment, catch and effort data for each of the key species are determined for the geographic range of the fishery (Donhoue 1993). Within these ranges the catch rates by one-degree geographic blocks are determined by dividing reported catches by nominal effort. The overall annual catch rate is then calculated by averaging the block catch rates and incorporating adjustments for the area fished within each block, and areas within the range where no fishing takes place (Simpfendorfer et al. 1997). Effective effort, the effort directed at a particular species is calculated by dividing the catch by the average annual catch rate. The effective effort also allows for an annual 2% increase in the efficiency of the fishing fleet to account for the introduction of new technology (e.g. GPS, colour echo sounders) and fishing experience.

ii. Carcharhinus obscurus

Catch-per-unit-effort information is calculated for C. obscurus using the same method as for the other key species. However, the biology of C. obscurus, and the nature of its fishery make CPUE a poor indicator of stock abundance for C. obscurus. To understand this problem consider F. macki. This species is caught only as adults, or sub-adults, and so the impact of fishing can be observed almost immediately in a drop in the abundance of neonates, which at significant levels of fishing translates to a reduced stock abundance (and so hopefully catch rates) a few years later as the neonates grow and recruit to the fishery. In the case of C. Obscurus, where most of the individuals caught by the fishery are less than one year old and have an age at maturity of approximately 20 years, at least this length of time will pass for the impact of fishing to be seen in recruitment to the fishery. CPUE in the C. obscurus stock is therefore an indicator of the impact of fishing about 20 years before and so not really a meaningful indicator by which to manage a fishery. Where the CPUE data will be useful is in the investigation of the stock recruitment relationship. However, with only 22 years of data available from Western Australian waters, significantly more time is required before such an analysis is possible.

Since CPUE is a poor indicator by which to manage the stock the FWA has embarked recently upon an assessment of C. obscurus based on the estimation of age-specific exploitation rates from a tag and release study. This technique uses the age-specific exploitation rates in a demographic model of the C. obscurus population, and so does not require an index of abundance.

5.3.2 Biological advice review process

The stock assessments are undertaken by the Shark Section of the Fisheries Research Division of the FWA and are reviewed internally by research staff, including scientists with a high level of expertise in stock assessment. Some of the data used in the stock assessments has also been peer reviewed in the process of publication, and it is anticipated that more biological data, as well as the assessments, will be published in scientific journals in the future.

5.3.3 Biological management reference points

The biological reference points used in the management of the WATSF are those included in the management objectives (Section 3.2) for the WADGDLFMAC. That is, a minimum of 40% of total virgin biomass. This is a target reference point for the fishery, there is no limit reference point. The WADGDLFMAC set a date to achieve these levels of 2010 for F. macki and M. antarcticus, and 2040 for C. obscurus.

The target reference point of 40% of virgin total biomass was selected on the advice of the FWA researchers. The recommendation of this level was made on the basis that the strong relationship between stock and recruitment in shark populations meant that a relatively large proportion of the biomass must remain to ensure sufficient recruitment to support a fishery. There was only limited data available from other shark fisheries on the level at which maximum yields were obtained and the level of biomass at which they collapsed or became economically unviable. Thus 40% was selected largely on the basis that invertebrate and teleost fisheries typically collapse at biomass levels between 15% and 25% and so the level for sharks would need to be significantly higher.

5.3.4 Sustainability of the resources

i. Furgaleus macki

The status of the F. macki stock in southern Western Australia is assessed using an age-structured population model. The structure of the model has been described by Simpfendorfer et al. (1996) and Simpfendorfer et al. (1997). The model incorporates biological information, catch and effort data, and fishery data (e.g. mesh selectivity) to predict the current biomass level and the projected biomass level under different future fishing scenarios. The model is stochastic and allows for the estimation of risk of achieving specified biomass targets, in particuliar, 40% of virgin biomass by 2010.

The most recent stock assessment was produced in January 1997 (Simpfendorfer et al. 1997). This assessment concluded that the current level of biomass was 28.7% of virgin biomass (95% confidence interval 19.2% to 38.1%). The probability that the 40% of virgin biomass objective would be reached by 2010 under a range of future effort levels (displayed as a proportion of the 1993/94 level of effort) is shown in Figure 9. This risk assessment indicates that a 50% reduction in effort from the 1993/94 level would be required to achieve an 80% chance of attaining the biomass objective. Maintenance of fishing effort at the 1993/94 level would result in a serious depletion of the stock, with a less than 10% chance that the stock would be above 40% of virgin. On the basis of this assessment the F. macki stock is considered over-exploited and in need to stock rebuilding (Simpfendorfer et al. 1997).

ii. Mustelus antarcticus

The status of the M. antarcticus stock in southern Western Australia is assessed in the same way as the F. macki stock (see i. above). The most recent assessment indicates that the best estimate of the current biomass level is 41.4% of virgin biomass (95% CI 25.8–51.7%) (Simpfendorfer et al. 1997). The probability that the 40% virgin biomass objective would be reached by 2010 under a range of future effort levels (displayed as a proportion of the 1993/94 level of effort) is shown in Figure 10.

iii. Carcharinus obscurus

Historically the status of the C. obscurus stock has been assessed using the same age-structured model approach as applied to F. macki and M. antarcticus. However, this style of assessment is not appropriate for C. obscurus given the long period from birth to maturity and the age of the sharks targeted by the fishery. To overcome the limitations of the catch and effort based approach the impact of fishing on the stock is now assessed using age-specific exploitation rate data derived from a tagging programme. The technique is described by Simpfendorfer (in review). The exploitation rates are included in a demographic model and population parameters calculated. Sensitivity analysis is used to explore the uncertainty in the parameters.

Figure 9

Probability of F. macki biomass being greater than 40% of virgin by the year 2010 at varying levels of fishing effort. (Simpfendorfer et al. 1997)

Figure 10

Probability of M antarcticus biomass being greater than 40% of virgin by the year 2010 at varying levels of fishing effort. (Simpfendorfer et al. 1997)

Current exploitation rates for 0+ age class are between 20.7% and 28%. Exploitation rates for older age classes are much lower than for the 0+ age class. The best estimate of the impact of this level of fishing on the stock is that the population is sustainable, with the intrinsic rate of population increase at above 2% (Simpfendorfer in review). The sensitivity tests indicate that the only situations in which the population may decline is if natural mortality has been significantly under-estimated. This style of assessment is much more simplified that those for F. macki and M. antarcticus and does not take into account increases in productivity in response to fishing and so is likely to underestimate the sustainability of the stock. The assessment also assumes that there is no mortality of individuals older than 6 years. Simpfendorfer (in review), however, notes that there is an unquantified mortality of these older individuals that may lead to the stock becoming over-exploited.

5.4 Perspectives on resource assessment advice

5.4.1 Manager's perspective

Information on the perspectives on resource assessment advice for the WATSF was derived from discussion with Fisheries Western Australia's Management Officer responsible for shark fisheries. He made the following point:

• From a fishery managers perspective the resource assessment advice has been good in that it has provided a clear focus for the WADGDLFMAC's consideration of future management arrangements. Without these assessments it would not have been possible to demonstrate a need for the reduction in fishing effort that has been recently recommended by the WADGDLFMAC.

5.4.2 Users perspective

Information on the users' perspective on the resource assessment advice was derived from discussions with a number of fishers. They raised a number of points:

• The main criticism of the assessment advice was that at times they found it difficult to understand, particularly the techniques used.

• At times they found the status of the resources difficult to correlate with their own observations in the fishery.

• Most fishers were happy with the resource assessment advice and appreciated the efforts of the researcher who spent substantial periods of time at sea on commercial vessels collecting data.

5.5 Discussion

The level of resource assessment in the WATSF is amongst the most detailed in any shark fishery, probably only exceeded by Australia's Southern Shark Fishery. The level of assessment reflects the importance that the Western Australian and Australian Governments place on fisheries management and fishery sustainability. The introduction of the management plans for the JASDGDLLEF and the WCDGDLIMF has meant that there was a need for quality, detail, and ongoing resource assessment advice for the major shark species. Without such advice it would have been impossible to demonstrate the need for management, or support the ongoing management of the WATSF.

The resource assessment process has been aided by the collection of species specific information from all commercial fishers since 1975. These data have provided abundance information (in the form of CPUE data) over a twenty year period as the fishery developed from a small part-time fishery to a targeted full-time fishery. The collection of fishery data has been complemented by a range of biological studies that have provided data on the life history of the main species. The fishery and biological data have been fundamental in the development of age-structured models and risk assessments for F. macki and M. antarcticus.

The assessments for F. macki and M. antarcticus rely on CPUE and for the commercial fishery as the measure of stock abudance. Difficulties exist in the use of CPUE data as an index of abudance, includign hyper-depletion, hyper-stability, changes in fishing behaviour, fishing effort efficiency changes and others. The results of the assessments must therefore be used with these difficulties in mind. However, there appear to be few alternatives to the use of CPUE data given the revenues from the fishery. Fishery independent surveys would need to be of considerable size and complexity to adequately evaluate changes in stock abundance. Recent tagging programmes may provide an avenue for including non-CPUE data in assessments. However, these studies have been of limited size and would need to be continued to provide ongoing data.

The assessment of the status of the C. obscurus stock using mostly tag recapture data has removed the reliance on CPUE data for this species. To be effective the tagging on which this assessment is based must be ongoing to provide information beyond the next few years. The use of a static demographic model also means that the response of the stock to fishing is not accounted for and so the assessment is pessimistic in its outcome.

The biological reference points chosen for the main commercial species are target reference points. As the 40% of virgin biomass targets were selected relatively arbitrarily, more work needs to be done to demonstrate their suitability. However, the lack of data from other shark fisheries on which to base this analysis will make it a difficult task. Consideration should also be given to setting limit reference points so that in the event of further stock depletion decision makers have a level at which to initiate urgent remedial action for the fishery. Again, however, the lack of data from other fisheries will make the selection of these points difficult.

6. THE LAW AND ENFORCEMENT

6.1 Legal status

Management of both the JASDGDLLEF and the WCDGDLIMF is empowered under Western Australia's Fish Resources Management Act 1994. In the case of the JASDGDLLEF, which is a Joint Authority Fishery (see Section 4), this power is shared with the Commonwealth. Under the State legislation the resource is considered to be a common property resource.

Fishers are required to hold a valid fishing permit for either the JASDGDLLEF or the WCDGDLIMF. These fisheries have limited entry and no new licences are being issued. If a fisher wishes to fish in either of these fisheries he or she must purchase a licence. Along with the requirement to hold a valid licence is the need to hold sufficient time/gear units to operate in the fishery (see Section 4.2.6). The time/gear units are tradable between licence holders.

6.2 Enforcement problems

A range of enforcement problems are encountered in the WATSF

• fishing without nomination of time/gear units
• fishing without a permit (i.e. not holding a JASDGDLLEF or WCDGDLIMF licence)
• illegal fishing gear (e.g. incorrect mesh size or mesh drop)
• using gear in excess of entitlement
• fishing in closed waters.

6.3 Surveillance and compliance

Surveillance and compliance in the WATSF is the responsibility of Fisheries Officers as defined under the Fish Resources Management Act 1994. Fisheries Officers undertake a number of tasks in relation to surveillance and compliance:

• measurement of net length at sea using hand-held GPS equipment
• checking that time/gear units are nominated when fishing occurs
• checking that gear and vessels conform to legislative and regulatory specifications.

The majority of surveillance operations are shore-based as patrol vessel capability over most of the JASDGDLLEF is limited. Fisheries Officers at times accompany fishers to sea to carry out net length checks. There is also a relatively high degree of self-regulation in the WATSF in relation to checks on the nomination of time/gear units. This is achieved by publication of all nominations which allows fishers to know when each vessel should be working. Vessels suspected of violating the regulations are reported to Fisheries Officers. In some situations aerial surveillance of closed areas has been carried out by Fisheries Officers.

6.4 The legal process

Fisheries Officers are responsible for issuing of infringement notices for offences under the Fish Resources Management Act 1994. The culpability of offenders and associated penalties are decided by the courts. Penalties for offences are specified in the Act. Most penalties are of a monetary nature. However, the Act also allows for seizing of equipment used in illegal fishing, loss of licence and in rare situations custodial sentences. As well as the imposition of a standard fine, the Fish Resources Management Act allows the court to impose an additional penalty of ten times the commercial value of the catch from illegal fishing.

7. MANAGEMENT SUCCESS

7.1 Profitability of the fishery

No studies have been carried out on the profitability of the WATSF. As a result it is difficult to assess the economic viability of the industry. However, it is possibly to make some comments based on anecdotal information from fishers. A number of operators in the fishery appear to be making a profit on the basis of their ability to invest in new vessels and equipment. These operators are mostly those that have had a long association with the fishery. There have been some cases of operators leaving the fishery because of economic hardship. Where operators have faced economic hardship it is not possible to know if other economic factors have influenced their position. There also appear to be few people willing to currently invest in the fishery. The last licence sales were in the order of A$1500–2000 per time/gear unit, which values the entitlement of a full access vessel with 100 time/gear units at A$150 000 – 200 000. However, a number of operators have had their licences on the market for substantial periods of time without being able to sell them. It is not known if the lack of buyers is a reflection of the profitability of the fishery or the level of uncertainty associated with the management of the fishery given the need to rebuild stocks of whiskery sharks. It would be useful for an economic study of the fishery to be carried out so that aspects such as profitability, return on investment and dissipation of wealth could be determined.

7.2 Issues of equity and efficiency

In its current state the WATSF is not operating at the highest level of efficiency. There is a significant proportion of the vessels with relatively low catch rates or who do not even work. There is room for considerable efficiency increases in the fishery that would result in the number of vessels that could operate being reduced. The need to reduce the number of vessels if efficiency increased would arise from the need to meet the biological reference points set in the management objectives of the fishery. A significant reduction in the number of vessels as a result of efficiency increases would have obvious implications for the towns from which the vessels operate as many crews could be out of work. However, fishers who remained in the fishery would most likely increase their earnings.

The management objectives for the fishery (see Section 4.2) include three relating to economics of the fishery and equity in the management process. Factors such as economics, equity and social impacts are all considered during the deliberations of the WADGDLFMAC. These issues are of particular interest to the fishers on the committee and are often discussed at length. As these principles are in the management objectives all of the recommendations from the WADGDLFMAC must take these matters into account. Further, ability to comment on these issues is available to any person when a management plan is introduced, or changed, due to requirements for public comment periods with the Fish Resources Management Act 1994.

8. MANAGEMENT COSTS

The costs of managing the WATSF have not been released by the FWA. Most of the costs of research over the past 5 years have been met by grants from the Fisheries Research and Development Corporation. These grants have totalled over A$900 000 over six years (to mid-1999).

In 1995 the FWA moved towards a cost-recovery model in relation to the management of fisheries. Initially only the larger, high revenue, fisheries were placed on full cost recovery. Small fisheries (including the shark fisheries) are currently on a partially cost-recovered system with the view to moving some of these fisheries to full cost-recovery. The cost-recovery process encompasses all aspects related to the management of the fishery including research, licensing, policy setting (including the management advisory committee system), and compliance monitoring. There are concerns within the WATSF that the movement to the cost-recovery system will result in a dramatic increase in licence fees, reducing the economic viability of many operators. Current licence fees are calculated on a per-unit basis. In the JASDGDLLEF the licence fee is A$19 per unit, and in the WCDGDLIMF the fee is $52 per unit. The large difference in the per-unit fee between the two management areas is due to the small number of units in the WCDGDLIMF to which similar costs to the JASDGDLLEF are attributed. However, the method of calculating the per-unit fee for the WCDGDLIMF is currently under review and may be changed in the future (T. Bray, FWA, pers. comm.).

The movement to full cost-recovery management would undoubtedly have implication s for the management of the fishery. The increased licence fees would force the WADGDLFMAC, the Minister of Fisheries, and the Fisheries Department of Western Australia, to reassess levels of research, running costs of the WADGDLFMAC, enforcement, policy support, and licensing issues.

9. ACKNOWLEDGEMENTS

The assistance of Tim Bray of Fisheries Western Australia in providing information and time is gratefully acknowledged, especially in relation to the Sections on Management Perspective. Thanks also to Terry Walker, of the Marine and Freshwater Resources Institute in Victoria for information in relation to school and gummy sharks, Dave Johnson of the Australian Fisheries Management Authority for information relating to the Commonwealth management of Fisheries, and Kevin Donohue of Fisheries Western Australia who has had a long involvement with the shark fishery. Finally I would like to thank the commercial shark fishermen who I talked with and who happily shared their thoughts on the management and assessment of the fishery.

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