DENMARK

The Kingdom of Denmark, an archipelago between the North and Baltic Seas, forms a bridge between Central Europe and the Scandinavian Peninsula. Inland from its highly dissected coast, is a low-lying area of glacial moraines, undulating plains and low hills furrowed by tunnel valleys. Primarily a land of farms and small towns, it is dominated by the metropolis of Copenhagen.

Lacking either mineral or hydroelectric resources, Denmark is intensively cultivated, has a seagoing heritage, and is increasing its industrialization.

Lacking real rivers and large lakes, the country's fisheries are largely marine. There are, however, some commercial fisheries in its shallow lakes, and recreational fishing in both lakes and streams. Trout and eel populations are dominant and cyprinids are little desired. Trout culture in fresh water has long been an outstanding development.

Heavy land and water use causes severe pollution problems and increasing eutrophication. Previously, recognition of environmental needs and the value of recreational fisheries were developing slowly, but have increased considerably during the past decades.

¹ In addition to continental or metropolitan Denmark, the Kingdom includes the Faeroes, a group of islands totalling 1 399 km² which lies north of Scotland, and Greenland, the largest island in the world, which covers 2 175 600 km², although only 341 700 km² is ice-free

Denmark, in northwestern Europe, lies between 54°34' and 57°45'N latitudes and 8°5' and 15°12'E longitudes.

Metropolitan Denmark, between the North Sea and the Baltic Sea, consists of the northern two-thirds of the Jutland Peninsula (29 775 km² or 69 percent of the total area) and 483 islands, most of which are in the Baltic area and of which 97 are inhabited. The largest of the islands are: Zealand (Sjaelland) (7 448 km²), Funen (Fyn) (3 486 km²), Lolland (1 283 km²), Bornholm (588 km²) and Falster (514 km²). The N–S length is 358 km and E–W width 475 km. The glaciated surface is uniformly low, the average altitude being about 35 m with a range from -2 m to only 173 m.

Jutland's western boundary is the North Sea, its northern boundary the Skagerrak separates it from Norway, the Kattegat separates it from Sweden, and to its east lies the Baltic. Denmark has only one land boundary, a southern neck of 67.7 km, separating Jutland from the Federal Republic of Germany.

The Danish area is one of the most dissected land masses in Europe. Its coastline, ten times the shortest possible length of an island having the same area, is 7 314 km in extent. There is a considerable development of offshore bars and lagoons on the western coast of Jutland, and many open bays and long winding inlets on its east coast.

All of Denmark, except for the granitic island of Bornholm, is a low and level continuation of the North European Plain. The surface relief is characterized by deposits of glacial moraine overlying limestone, which form undulating plains alternating with gently rolling hills, interspersed with small streams, lakes and ponds.

Extending down central Jutland is a chain of hills marking the terminal moraine of the last glaciation. West and south of this line is a series of sandy outwash plains, once a vast heathland with infertile podzol soils. East of the line, the country, including the islands, is generally mantled with boulder clays or porous loams, and is more fertile, more wooded and better populated.

The original North-European deciduous forest of beech, oak, elm and lime now survives in only a few localities. Although about 10 percent of the country is forested, most of this area has been planted and includes exotic conifers such as spruce and Scots pine. Dune, heath and bog cover about 8 percent of Denmark.

4. CLIMATE

The climate is temperate with mild damp weather. Winter climates are tempered by the Gulf Stream so that the mean temperature in the coldest month is about 12°C higher than average for its latitude (56°N). Similarly, the Baltic waters which separate Denmark from the bulk of the continent generally temper its climate. The mean annual temperature is about 7.9°C. The mean temperature of the warmest month (July) is 16.6°C; that of the coldest month (February) is -0.4°C. The highest temperature recorded is 36.4°C, the lowest -31°C.

The mean annual precipitation is 664 mm, ranging from about 800 to 400 mm. Rainfall, fairly even throughout the year, is highest in August and October and lowest in winter and spring.

Snow falls between 20 and 40 days between October and May, but is usually concentrated in the January–March period.

Sea ice is rare off western Jutland, but the calm and less saline areas east of Jutland may freeze for several weeks during severe winters, creating drift and pack ice.

The growing season based on the average period with temperatures above 3°C between spring and autumn is generally between 1 April and 30 November or 240 days (Wallen, 1961).

The annual evaporation from a free water surface in Denmark is 600 mm. The evaporative rate in general is around 400 mm.

The length of day ranges between 7 and 17.5 hours throughout the year with about 1 800 sunshine hours.

5. HYDROGRAPHY AND LIMNOLOGY

The total area of inland water in Denmark is about 70 000 ha or 1.6 percent of the total area (Danmarks Statistik, 1989, and Table 1)¹. Ovesen (1977) states that the lakes and water courses of Denmark are 1.5 percent of the total area, and Sømme (1961) states that the lake area is 1.4 percent of the total area. EIFAC (1989) gives the area of inland water in Denmark as 50 000 ha or less than 1.2 percent of the total area; a figure that appears to be too low.

¹ Danmarks Statistik (1988) lists the distribution of Denmark's inland waters as follows: Jutland (462.90 km²), Zealand (183.45 km²), Funen (26.44 km²), Lolland-Falster (23.74 km²) and Bornholm (3.15 km²) - totalling 699.68 km²

The approximate annual runoff from rainfall is 260 mm or 11 000 million m³; there is no discharge from upstream countries (Van der Leeden, 1975). Most of the runoff forms ground water which later percolates into water courses. From a use standpoint, ground water is pre-eminent in Denmark (see section 6).

5.1 Rivers (Åer)

There are no long or important rivers in Denmark because of its small size, low elevation and relatively low rainfall. Only two rivers, both in Jutland, attain more than 100 km in length and only five more exceed 60 km. The longest river in Zealand is 83 km, and the longest in Funen is 53 km. All in all, there are about 15 000 km of major rivers and streams (Dahl, 1982). The area is listed as being 7 000 ha by EIFAC (1989); a figure which is, of course, a rough estimate.

The rivers of Denmark, which are primarily rainfed, generally have a maximum flow in spring, a secondary maxima during the autumn (due to precipitation) and a lower discharge in summer than in winter due to evaporation. The streams of western Jutland, where soils are poor, are relatively low in nutrients (150–300 uS/cm) and attain water temperatures of 12–15°C in summer. The streams of eastern Jutland which rise in morainic soils are rich in nutrients (200–600 uS/cm) and also influenced by biologically treated sewage. In summer they may reach temperatures above the optimum for trout (i.e., over 15°C) and even close to 25°C (Rasmussen, 1984). In general, Danish streams are small, sluggish and without falls. They are usually silty or sandy except in Bornholm, where they have a rock base. They have a high biomass of aquatic macrophytes in summer.

The principal river is the Gudenå, with a basin of 2 700 km². It rises in central Jutland and flows north for 158 km to Randers Fjord on the Kattegat, draining a series of lakes en route.

The Storå also originates in central Jutland and flows north for about 100 km to Nissum Fjord on the North Sea. Three other Jutland streams, the Skjernå (94 km), Omne å and Varde å flow west to the North Sea. These are trout streams as are also the Simested å, Sneum å, Konge å and Karup å (78 km).

5.2 Lakes (Søer)

There are about 500 lakes and ponds in Denmark. Denmark/EIFAC (1974) gives their total area at about 61 200 ha. Dahl (1982) says that the lake area is about 43 000 ha. EIFAC (1989) lists their total area as 42 000 ha, 120 of the lakes have areas exceeding 0.5 km². The lakes, which are mostly small and shallow, are found in depressions in the glacial deposits or in valleys blocked by moraines. Some are kettle lakes, others in tunnel valleys (originally cut by sub-glacial meltwater) have ribboned out into chains.

Chemically, they range from acid and clear waters (these mostly in the sandy heath or dune soils of West Jutland) to turbid, eutrophic and brackish waters. An annual gross production of about 70 g C/m² seems to be the maximum level for the non-culturally affected lakes in Denmark, but the majority of the Danish lakes represent a eutrophication level, which, expressed as annual primary production is close to 400⁺ g C/m² (Riemann and Mathiesen, 1977). There are extremely high levels in some lakes due to heavy sewage loading.

The largest lake is Lake Arresø on the island of Zealand, joined by a canal to Roskilde Fjord. It has an area of 40.6 km² and is about 8 km in diameter. Arresø has a mean depth of 2.8 m and a maximum depth of 6.5 m. Nearly uniform in oxygen content and temperature, it is highly eutrophic as it receives sewage. European eel (Anguilla anguilla), pike-perch (Stizostedion lucioperca) and bream (Abramis brama) constitute 90–95 percent of the total population (Nielsen, 1977).

The second largest lake in Denmark is the dimictic temperate Lake Esrom (Esrum) also on the island of Zealand, receiving its water supply from small brooks and ditches and connected to the Kattegat by a canal. Esrom is 8–9 km long and 2–3 km wide, with an area of 17.3 km², mean depth of 12.3 m, maximum depth of 22 m, volume of 213 million m³ and retention time of 8.5 years. A eutrophic lake with high calcium content and high stability, it has little or no oxygen at its greatest depth from July to November. Its ice-cover ranges from 0 to 112 days; the lake is ice-free approximately every five years. Its average fish catch over a period of 12 years consisted primarily of an assemblage of roach (Rutilus rutilus), bleak (Alburnus alburnus) and ruffe (Gymnocephalus cernua), followed by European eel, European perch (Perca fluviatilis), bream, and tench (Tinca tinca) (Jonasson, 1984). Another large lake in Zealand is the 13.3-km Lake Tisso.

The largest lake in Jutland is Lake Mossø with an area of 16.9 km², mean depth of 8.6 m and maximum depth of 32 m. The eutrophic Arreskov Lake with an area of 3.54 km², is the largest lake in Funen. The deepest lake in Denmark, 36 m, is Furesø in Zealand.

5.3 Reservoirs (Opstemningssøer)

In 1962, there were five reservoirs, totalling about 700 ha, where commercial fishing was practised (EIFAC, 1964). This amount has now increased to 1 000 ha, according to Denmark/EIFAC (1977, 1989) and EIFAC (1989).

5.4 Other Waters

Judged by their degree of penetration into the land masses, lowered salinity and type of fauna, Denmark may be said to have a large number and variety of “semi-inland” waters: “fjords”, sheltered bays, estuaries, lagoons and creeks.

The term “fjords” as used in Denmark deserves explanation. First of all, they are not at all comparable to the long, steep-sided glaciated inlets of the sea common in Norway. The Danish fjords, probably better termed “fohrden”, on the east coast of Jutland represent drowned tunnel valleys cut by glacial meltwater in unconsolidated material. Wide at the mouth, they narrow inland, the sides are rarely high, and they are navigable. Another type of Danish fjord found on the west coast of Jutland is merely a long spit-enclosed bay or lagoon, sometimes termed a “haff”.

The largest (1 400 km²) and most marine fjord in Denmark is the Limfjord, which cuts completely across the northern tip of Jutland to join the North Sea with the Kattegat. The second largest fjord complex is the Isefjord in northern Zealand, about 400 km² in extent.

These inner and coastal areas vary in their degree of salinity, e.g., that of the Kattegat is about 20–30 ppt, but in the Great Belt (between Zealand and Funen) it drops to 15 ppt. Some of these areas are open, some almost closed. They support a variety of fishes: eels and flounders (Platichthys flesus), are common in mesohaline waters while trout (Salmo trutta), whitefish (Coregonus spp.), pike (Esox lucius) and cyprinids are found in oligohaline areas.

Low winter temperatures, prolonged ice cover and low oxygen sometimes cause extensive mortalities in these waters. They are also subject to land reclamation (see section 6).

6. LAND AND WATER USE

Table 1

Pattern of land-use in Denmark, 1986

Source: 1987 FAO Prod.Yearb., 41 (Publ. 1988)

About 87 percent of Denmark's population is urban, with about 25 percent of the population living in an 800 km² area around Copenhagen. Neverthless, with almost 70 percent of its land devoted to agriculture, Denmark has one of the highest proportions in Europe of land devoted to cultivation. The natural soils are somewhat unsuitable but they have been modified by tillage and heavy use of fertilizers (extensive use has been made of manure) in several centuries of intense cultivation. About 244 kg/ha/year of fertilizers were used in 1984. Extensive areas have also been reclaimed, sometimes with the loss of aquatic habitat. Since in the long run about 90 percent of Denmark's agricultural output is derived from animal production (livestock and dairy products), grain and root crops (especially for use as fodder) are the most important crops. Irrigation makes very little use of Denmark's surface waters, being used only supplementally and mostly with sprinklers, although overall about 9 percent of the country is irrigated (1986).

By the end of the 18th century, only 4 percent of the country was still forested but more than 10 percent is now forested - mostly through well tended plantation. Replacement must follow cutting, however, and Denmark ranks about twentieth in European roundwood production.

Mineral resources are almost lacking. There is some quarrying, production of cement, some sulphur peat and lignite, and mineral oil and gas from the North Sea. There has been river pollution from acid ferruginous wastes from lignite mines.

Despite the lack of iron, fossil fuels and hydroelectric power, and a late start in the field, industry now constitues about one-third of the GNP. Much of the industry is small. It is concentrated on industrial and construction materials, furniture, textiles, cement, brewing and food processing.

Almost all of Denmark's power production is thermal, using imported power or imported and Danish North Sea oil, some is geothermal and only a little is hydroelectric. The hydroelectric resources so abundant in other Scandinavian countries are almost lacking here due to the level terrain and small volume of stream flow. Of a total installed electrical capacity in 1987 of 8 557 000 kW, only 10 000 kW (1.2 percent) were hydroelectric. There were 120 hydroelectric plants in Denmark in 1978, but only 23 of these were operating and most are very small. The major hydroelectric power stations are on the Gudenå, Storå, Vardeå and Kolding å Rivers. They have a minor effect on fisheries. In 1980 Denmark decided not to develop nuclear power.

Denmark has a well organized system of rail (about 3 000 km), ferry and ship transport and a road density of 1.7 km/km². Private automobile ownership is about 301 per 1 000 (1986). The lower Gudenå is partly navigable.

Denmark has long been an important marine fishing nation, with almost 15 000 professional and occasional saltwater fishermen in 1977 and a saltwater catch of 1 671 871 t in 1987. By contrast, the commercial catch in fresh water is negligible, constituting only about 0.2 percent of the total catch (Dahl, 1982) (see section 7.1). There is, however, a thriving trout culture industry, and a fur-farming industry of about 2 400 farms which utilizes fish as food. The apparent domestic consumption of fish for food is about 40 kg per caput per year, measured in live weight (FAO, 1986).

Land reclamation through drainage has been a feature of Danish resource use for over 150 years (see section 9.2). Furthermore, according to law, land drainage and reduction in flood risk are considered the major purposes of the streams, and there are definite rules for most streams for aquatic weed removal and other maintenance work to ensure these ends. Weeds are normally cut once or twice a year by hand or by boats.

The land and water uses affecting fisheries have primarily been those causing pollution or at least the siltation and eutrophication of lakes and streams. The problems are aggravated by the intense use of the land, the slow-moving nature and small volume of the streams, and the shallowness of the lakes. Many of the polluting effluents derive from agricultural industries such as beet sugar factories, flour mills, slaughter houses, and dairies, from ensilage, and from agricultural chemicals. A good deal of industrial waste is admitted to sewers and treated with the sewage.

Fish farming is also an important source of organic pollution in Denmark's small streams (some “rivers” are only one metre wide). In Jutland, it has been estimated that 30–35 percent of the total discharged organic matter is derived from fish farms. This equals the untreated organic loading of a population of over one-half million people (see Table 2).

Table 2

Organic loading in the Simested River (t/year)

Source: Reproduced in Hansen (1979) and Warrer-Hansen (1982) based on Water Quality Institute (1978)

Despite pollution from fish farms, their effluents must be considered as relatively clean waste water, having concentrations much lower than those of biologically treated domestic waste water.

Of all European countries, Denmark makes by far the greatest use of its ground water, 97 percent of its total water use comes from this sources (ECE, 1978). The greatly increased extraction of ground water, especially in Zealand, has caused the disappearance of some good trout streams.

Estimates of total water use in Denmark are shown in Table 3, and somewhat similar estimates made by the Danish Pollution Council (1971) showed a total demand of 720 million m³/year in 1970 and 1 070 million m³/year in the year 2000¹. It may be noted, however, that the estimates of use for the year 2000 made by both of these authorities had already been exceeded in 1982 when a total water consumption in Denmark of 1 335 million m³ was recorded. This dropped, however, to 1 100 million m³ in 1984 (Denmarks Statistik, 1989).

¹ Cited in Van der Leeden (1975)

The demand by thermal plants was not indicated by the Danish Pollution Council. Instead a relatively high demand was shown for fish farms: 50 million m³/year (or 7 percent of the total demand) in 1970, and 25 million m³/year (2.3 percent of the total demand) in the year 2000.

Table 3

Estimates of freshwater abstraction in Denmark, 1977 and 2000

Source: Denmark, Government of (1978)

In this regard it must be realized that - compared with most manufacturing processes - trout farming requires a very large water consumption; e.g., a Danish fish farm producing 50–75 t annually uses about 500 1/sec, which equals the daily consumption of a population of 170 000 people (Warrer-Hansen, 1982).

7. FISH AND FISHERIES

The principal fishes found in the small streams and lakes of Denmark are shown in Table 4.

Of the total fish fauna in streams, eel and brown trout constitute approximately 10 and 75 percent, respectively (Larsen, 1955). Of the diadromous fishes, the eel is by far the most important in Denmark commercially, being found and caught in practically all types of Danish fishing waters as well as in the sea. Some elvers are stocked in lakes. The sea trout (Salmo trutta) is also caught in fresh waters, but mostly in the sea. Atlantic salmon (Salmo salar) is uncommon today in Denmark's fresh waters. For example, it has been extinct in the country's largest river, the Gudenå, since 1924, but a few salmon are still found each year in rivers like the Storå and Skjern å.

Table 4

Principal inland fishes of Denmark

^a Introduced

At present, attempts are being made to restore sea trout populations by creating artificial spawning areas and to restock some salmon rivers. Denmark has, in fact, purchased salmon smolts for stocking from Sweden, and from 1980 onwards was to pay for the release of smolts that correspond to its catch quota (Larsson, 1980).

In recent years, the introduced pike-perch (Stizostedion lucioperca) has become of increasing importance in both the commercial and recreational catch in Denmark¹. Since 1925, when the total yield of pike-perch in Denmark exceeded 1 000 kg for the first time, the yield increased up to 1 935 kg and then stabilized to about 5 to 8 percent of the total catch in Danish inland waters or 40 to 90 t/year. With respect to the commercial catch in Denmark's inland waters, pike-perch is today second in weight and value, being surpassed only by the catch of eel. An average yield of about 5 kg/ha/year is normal for Danish pike-perch lakes. The best yield comes from deep freshwater lakes, the lowest from shallow, brackish waters. Slow to catch on as a sport fish, the pike-perch has now become highly prized by Danish anglers. It is also increasing in value as a predator on the less-valued cyprinids, a role formerly held by pike. The increasing eutrophication and turbidity of Danish lakes makes them more suitable for pike-perch than pike.

¹ Pike-perch were first introduced from Germany into Denmark in 1879. The stocking failed and the first successful stocking, also from Germany was in 1898, followed by other plants from Sweden and Germany. It is now found in 70 Danish freshwater and brackish lakes (Dahl, 1984a)

Two other introductions in Denmark are quite recent: the results are in abeyance. The grass carp (Ctenopharyngodon idella), introduced into Denmark in 1965 from the USSR, was first stocked in Danish natural waters in 1968 with follow-up stocking from other countries to control aquatic weeds. Silver carp (Hypopthalmichthys molotrix) was first stocked in a Danish lake in 1981. In some cases, weed reduction has been considerable, in others it has been limited, and many deaths have been reported of these Chinese carps - either from cold or from asphyxiation (Markmann, 1984).

Table 5

Nominal catches in the inland waters of Denmark, 1965, 1970, 1975, 1980–87 (in tons)

0 - Probably nil, negligible or insignificant; or less than 50 t during 1965–73, or less than half a ton during later years.

Source: 1965 Yearb.Fish.Stat.FAO, 36 (Publ. 1974) 1970, 1980–83 FAO Fish. Dept. Fishery Statistical Database (FISHDAB), 1984–87 Yearb.Fish.Stat.FAO, 64 (Publ. 1989)

Table 5 illustrates the commercial “catch”, as reported to FAO during the 1965–87 period for the inland waters of Denmark as does Table 6 for the freshwater and diadromous fishes reported caught by Denmark in the Northeast Atlantic.¹ It is presumed that the Atlantic-caught “freshwater fishes” are caught in oligohaline zones of the Baltic. It is obvious that the “catches” of trout shown in Table 5 are mostly cultivated rather than wild fish (see section 7.2). However, the decided discrepancies shown between the FAO report (Table 5) and the reports from Denmark made to EIFAC (Tables 7 and 8) for inland water catches during the 1973–80 period cannot be explained (see section 7.1.1).

¹ The enormous (by comparison) catch of “sea trout” by Denmark in 1986 of 3 775 t cannot be explained. It is reasonable to suspect its accuracy

7.1 Capture Fisheries

7.1.1 Commercial fishing

In Denmark, the Ministry of Fisheries considers true commercial fishing to be an activity where the product (or harvest) is offered for sale (cf. section 7.1.2)

It is obvious from Table 7 that the inland commercial capture fishery in Denmark in 1973 (a minimum reported catch of about 548 t) was dominated by the catch of cyprinids (56 percent), followed by eel (27 percent), the two percids (12 percent) and pike (4 percent). These four groups constituted 99 percent of the catch in 1973. The river catch was completely dominated by the catch of eels (96 percent). The catch in lakes was composed largely of cyprinids (56 percent), eel (25 percent), pike-perch (10 percent), perch (5 percent) and pike (4 percent). In the reservoirs, cyprinids led with 70 percent, eel followed with 28 percent and pike was third with 2 percent.

The catch statistics for 1973 in Table 7 present quite a different picture than do those in Table 5 from FAO for the same year, for example, a minimum catch of about 300 t of miscellaneous freshwater fishes as compared with Table 5's less than 50 t (at maximum) of freshwater fishes, and a minimum catch of 150 t of eel compared with FAO's 100 t.

Similarly, comparison of the FAO statistics for inland water catch in Denmark with those shown in Table 8 show decided discrepancies, e.g., the earlier catches for eel and unidentified freshwater fishes are decidedly smaller in the FAO report. Furthermore, EIFAC (1989) lists the annual commercial catch by 300 professional fishermen in Denmark's inland waters as 637 t.

Table 6

Nominal catches of freshwater and diadromous species in Marine Statistical Fishing Area 27, Northeast Atlantic by Denmark, 1965, 1970, 1975, 1980–87

- This category not listed this year

0 - Probably nil, negligible or insignificant; or less than 50 t during 1965–73 period, or less than half a ton during later years

n.e.i. not elsewhere included

^a Termed “sea trout” from 1984 onward

Source: 1965 Yearb.Fish.Stat.FAO, 36 (Publ. 1974)
1970–80 FAO Fish.Dept.Fishery Statistical Database (FISHDAB)
1984–87 Yearb.Fish.Stat. FAO, 64(Publ. 1989)

Table 7

Partial commercial catch in inland waters of Denmark, 1973 (in kg)^a

^a Represents returns from 22 782 ha of lakes, 999 ha of reservoirs, and unknown river area

^b Bream (Abramis brama), crucian carp (Carassius carassius), roach (Rutilus rutilus), rudd (Scardinius erythrophthalmus), burbot (Lota lota).

Source: Denmark/EIFAC, 1974

Such comparisons illustrate the difficulties of obtaining accurate statistics on the inland commercial catch in Denmark (or, for that matter, in many European countries) since in each case cited, the basic figures have been received from governmentally designated, although differing, sources.

Although the author's attempts (since 1976) to reconcile these differences have been unsuccessful, his feeling is that the statistics in Table 7 (even if partial) and those in Table 8 are more representative of both the quantity and composition of the Danish catch than are those of Table 5 for the same period.

Reference to Table 6 showing the catch by Denmark in Marine Statistical Area Northeast Atlantic may indicate a decline in the catch of “freshwater fishes” and also a decline in the catch of eel. With respect to eel catches, ICES/EIFAC (1976) states that Danish Baltic catches show no decrease and have been relatively constant over the last 15 years, but that the Danish catch per unit of effort in the Baltic has been decreasing for at least 30 years.

With respect to salmon catches by Denmark in the offshore fishery of the Baltic alone (Main Basin plus Gulf of Bothnia), annual catches cited by Larsson (1980) for the 1969–78 period are generally somewhat lower than those shown in Table 6 for the entire Marine Statistical Fishing Area 27. They range from a high of 1 469 t in 1969 to 810 t in 1978.

EIFAC (1989) gives the number of professional fishermen in Denmark as 300.

Commercial fishermen use a variety of gear in Denmark's inland waters: pound nets and trawls in the large lakes, fykes in lakes and streams, eel traps, longlines and beach seines. Offshore fishing in the Baltic for salmon is most important for Danish fishermen. Drifting longlines for salmon were introduced by the Danes in 1947 and dominated salmon fishing here in the 1950's. Their use continues, but in the Main Basin of the Baltic, drift nets dominate the fishery apart from November and December and are responsible for about 80 percent of the offshore salmon catch here by all participating countries (Larsson, 1980).

Table 8

Commercial catch in inland waters of Denmark, 1974–76, 1978–80, 1981–82, 1983–84, 1985–86

^a Mostly valueless species used for processing

^b For 1974–80, salmon and sea trout. For 1981–82, 68 t of sea and brown trout and 27 t of rainbow trout. For 1983–84, 72 t sea and brown trout, 1 t salmon and 26 t rainbow trout. For 1985–86, 70 t sea and brown trout, 1 t salmon and 11 t rainbow trout.

^c Total for the triennium was 1 594 t: 600 (1978), 489 (1979), and 505 (1980)

^d Total for the biennium was 1 353 t: 637 (1981) and 716 (1982)

^e Total for the biennium was 864 t: 412 t (1983) and 452 t (1984)

^f Total for the biennium was 846 t: 392 t (1985) and 454 t (1986)

Source: The weight of the individual species catch through 1981–82 was calculated by the author from the total weight of each year's catch (shown in the last line of the table) and species percentages given by Dahl (1976, 1978, 1982a, and 1984). Since the sum of his percentages in the columns for 1976, 1978–80, and 1981–82 do not equal 100, the individual species weights are, of course, not exact. The figures for 1983–84 and 1985–86 are from Denmark/EIFAC (1989)

7.1.2 Sport fishing

Unfortunately, for the sake of records, the Danish Ministry of Fisheries defines “sport fishing” as including both true angling (i.e., generally fishing with hook, rod and line) and part-time (or sparetime) fishing with more professional gear (mainly small fyke nets) but only for home consumption, not sale. In Denmark, the latter type of fishing which is performed mainly by riparian owners is not, in the Ministry's sense, true “commercial fishing” where the product is offered for sale. Both FAO and the author would term this “subsistence fishing”.

As late as 1980, even reasonably correct statistics on the sport or recreational fishery in Denmark were said to be lacking (Dahl, 1982), and one still cannot tell from government statistics the distinction between true angling and spare-time or subsistence fisheries (Denmark/EIFAC, 1989). Nevertheless, some past partial catch records which include those for the sport fishery will indicate the composition of the catch as well as its overall importance. Table 9 shows that in 1973 the leading species in the river catch by anglers and spare-time fishermen were: trout (46 percent), eel (40 percent) and pike (6 percent). In lakes and reservoirs the sport catch was: pike (33 percent), eel (24 percent), perch and pike-perch (23 percent) and trout (10 percent). The high percentage of eel in the catch is indicative of the effort by the spare-time fishermen rather than the sport fishermen according to Denmark/EIFAC (1989).

The total catch derived from non-commercial fishing in 1973 (using only these partial statistics) was almost one-fifth that of the reported commercial fishery in the same year (Table 7), and included a large percentage of high-value fish (salmonids and eel). In lakes and reservoirs, the catch by noncommercial fishing was only one-twentieth of the commercial catch, but in rivers it was five times that derived commercially.

Table 9

Partial fish catch by anglers and spare-time fishermen in inland waters of Denmark, 1973 (in kg)^a

^a Represents returns from 5 426 ha of lakes and 200 ha of reservoirs plus unknown river area

Source: Denmark/EIFAC, 1974

Both brown and sea trout are stocked in rivers and coastal areas for recreational fishing by privately managed liberation schemes under the aegis of Fishery Control Officers (see section 8.5). At present, about 56 percent of the Danish catchment areas are managed by annual stocking of about 1.6 million trout-fry, 350 000 summerlings, 200 000 yearlings, and 130 000 two-year-old trout (Rasmussen, 1984). There are a few inns, especially in Jutland, offering angling opportunities. There are also some “put and take” fisheries in some small water areas based mainly on rainbow trout. Rainbow trout that have escaped from rearing ponds also provide fishing.

Since no general licence is required for sport fishing in Denmark, it is difficult to determine the number of anglers. About 45 000 of them are organized into clubs (Dahl, 1982), and it was estimated (Gaudet, 1977) that circa 1972 Denmark had about 300 000 sport fishermen (then 6 percent of its total population). In 1980 it was again estimated that there were about 250 000 Danish anglers and perhaps 50 000 foreign anglers (Dahl, 1982). EIFAC (1989) estimates the number as 400 000. On the assumption that each resident angler spends about D.Kr. 1 500 on his sport each year, Dahl (1982) has estimated that the Danish sport fishermen spend about D.Kr. 375 000 000 annually.

7.2 Aquaculture

Denmark's aquaculture, centred in Jutland, is primarily the production of rainbow trout, although some brown trout and common carp have also been raised, and eel farming is in its infancy.

Statistics on aquacultural production of trout in Denmark differ depending upon the source. Some of these differences are due to rounding of figures, some may originate because the reporters have not distinguished between total national production and that which is exported (about 90 percent), some figures may be preliminary and then never amended, and some simply seem to be mistakes by author or printer. Table 10 shows total trout production (most of it rainbow) in Denmark as reported by authors likely to be considered standard sources and/or who have compiled their information from sources considered to be standard¹. The exact figures are not of as great importance as is the illustration of developmental trends.

¹ Brown (1983), for example, derives material from the Danish Society for Freshwater Fisheries, and the Fédération Européene de la Salmoniculture (FES)

The first Danish trout farms were established in Jutland in about 1890. Brown trout were the major species cultivated, but they were soon replaced by rainbow trout which, generally speaking, withstands higher water temperatures and has a faster growth rate. The industry matured rapidly. By 1961–62 there were about 500–525 trout farms. The total production in 1962 was 7 781 t of which 98 percent (7 657 t) was exported. By 1975 the number of fish farms had only risen to about 530 (of these, about 150 produced only eggs, fry and fingerlings) but the Danish trout export had doubled to over 14 000 t, and (according to Edwards, 1978) the total annual production had risen to 16 770 t. By 1983, the number of farms had not increased. There were 520, but trout production had increased to 24 700 t (see Table 10). There were still only 520 operating trout farms in Denmark in 1987. As has been pointed out in section 7 above, the trout “catch” shown in Table 5 is primarily representative of the commercial production of trout in Denmark, although its figures are at variance with many of those shown in Table 10, possibly because, in some instances, of inclusion of trout from the capture fishery.

Denmark has long been one of the world's most important trout producers.² There have been several good reasons for this: (i) the North Sea and the Baltic have been a source of cheap “trash” fish with high convertability for feed; (ii) transport of fish feed or trout has been facilitated by the short distances to travel over level terrain on good roads; (iii) an active interest both by government and industrial concerns in promoting the industry. Another factor in developing trout culture here has been the relative simplicity of the operation - at least originally. Although fry were produced in artificial containers (using either river or ground water), the larger fish have been reared in earthen ponds using water diverted from a river, led through the ponds and released again into the same river. However, as has become evident with the growth of the industry, use of surface waters and earthen ponds has increased the incidence of disease, and disposal of the effluent (faeces and unused food) has created severe environmental problems in Danish streams. The use of relatively low stocking densities has offset the disease problem to some extent, but waste disposal into streams conflicts with both the wild fishery and other water uses (see sections 6 and 9.2)

² In addition to the production of trout on the Danish mainland, there is a growing production of Atlantic salmon in the Faeroes. In 1989, these islands produced 10 000 t of cultured salmon (FES, 1989)

Almost all Danish trout are raised in fresh water, but there is a growing use of the brackish water (10–30 ppt salinity) of estuaries. In 1974, Denmark produced 12 000 t of trout from an area of 500 ha of fresh water and 120 t from 5 ha of brackish water (T.V.R. Pillay, pers.comm.). Circa 1989, EIFAC (1989) listed a production of 23 000 t annually from 520 farms with an area of 400 ha.

In 1978, about 100 t of trout were raised in sea water, and in 1983 this production reached over 1 000 t, and in 1989 about 3 000 t were raised. Trout weighing 200 g are put in sea water in April and 2 to 3 kg fish taken out in November–January. Land based farms using pumped sea water are generally used for this practice in Denmark since the country lacks the deep fjords and warm Gulf Stream water found in Scotland and Norway (Fish Farm.Int., 11(5):4, publ. 1984).

Most spawning of Denmark's rainbow trout occurs during the January–March period (some earlier), and after hatching it takes one to one and a half years to grow a 200-g fish. Most fry are hatched in April, are reared in concrete tanks until June–July, and then transferred to earthern ponds until the next April or July. Marketable sizes range from 180 to 350 g. Those from 180 to 250 g, one to two-year-olds, are portion fish, and the larger trout are often smoked. The Fédération Européene de la Salmoniculture (FES) estimated the entire 1989 production of rainbow trout in Denmark of 29 500 t as consisting of 25 000 t of “portion” trout and 4 500 t of “large” trout (FES, 1989).

Up to 1985 Denmark may have been the only country in the world which fed substantial quantities of fresh wet feed to cultivated trout because of the abundance of freshly caught trash fish. That year, however, the use of wet feed was totally prohibited and today all cultivated trout are fed on dry pellets. There is intensive research on the improvement of dry fish feeds, i.e., aiming at reducing the excretion of P and N and thus lessening stream pollution. Improved feeds have already (1989) reduced the production of suspended solids from 200 g/kg to 88 g/kg of fish produced.

In addition to supplying many countries with edible rainbow trout, there are extensive exports of trout eggs. Brown (1977) states that there are probably in excess of 100 million annually. Dahl (1986) says that Denmark produces about 30 t annually and Dahl (1988) records about 23 t of rainbow trout eggs exported from Denmark in 1986.

Rainbow trout are not stocked in Danish public waters although they may appear there as escapees from fish ponds. Some rainbow are stocked in sand or gravel pits for fee fishing. Perhaps 50 t of brown trout are raised annually to restock domestic waters and for export.

Common carp were also raised in Denmark but in small numbers. In 1973, 2.7 t were produced (Denmark/EIFAC, 1974). Christensen (1978) says that there is no market for carp in Denmark and that it is difficult to get them to breed there.

Circa 1984, some Danish firms were attempting to raise eel in using warm water (Fish Farm.Int., 11(2):7, publ. 1984). OECD (1986, 1987) states that 30 t of eel were produced in 1985 and 200 t in 1986. By the end of 1987, 30 eel farms were in operation, having produced 240 t in that year (Dahl, 1988).

8. OWNERSHIP, ADMINISTRATION, MANAGEMENT, INVESTIGATION AND AGREEMENTS¹

8.1 Ownership

Traditionally, fishing rights in Danish inland waters belong principally to the riparian owner. In some cases this may not be true, e.g., if special rights from ancient times can be established, or if the water is owned or administered by the State.

Fishing rights cannot be separated from the property and cannot be rented out for more than 25 consecutive years. These rights can, however, be separated from the property in case of water remaining in or coming into public possession.

Table 10

Production of cultivated trout in Denmark, 1962–89 (t)

^a The 1962–73 figures agree in Int.Res.Devel., 1979

^b In 1984, about 24 000 t of freshwater trout and 2 000 t raised in salt water

^c In 1985, about 24 000 t of freshwater trout and 3 300 t raised in salt water

^d Export plus home market; mostly rainbow trout

^e Aquaculture production, mainly rainbow trout

The owner may exploit the water himself or he may rent it to individuals, an angling club, or to a commercial fisherman. An angling club, in turn, may sell fishing privileges. With respect to Stateowned waters such as some lakes, the fishing rights may also be leased.

8.2 Administration

Three ministeries are concerned with Danish inland fisheries: Fisheries, Environmental Protection, and Agriculture.

8.2.1 Ministry of Fisheries

This Ministry, under a permanent Under-Secretary, is responsible for governmental activity in the field of both inland and marine fisheries from both an administrative and a scientific point of view. It is organized into seven Bureaux, which deal with such matters as enforcement of the Danish Inland Fisheries Act (1965), and Danish Sea Fisheries Act (1965), advice to local authorities and water courts in inland fishery problems, the collection of fishery statistics and other data, inspection, control of fish trade and the canning industry, etc. With respect to scientific and research services, see section 8.3 below.

One of the seven Bureaux deals specifically with aquaculture, inland fisheries and fishermen's status.

8.2.2 Ministry of Environmental Protection

In relation to fisheries this Ministry deals with inland and marine waters through two agencies:

1. The National Agency of Environmental Protection, which enforces the Danish Environmental Protection Act (1985), the Inland Water Act (1982), and the Water Supplies Act (1982);

2. The National Forest and Nature Agency, which enforces the Nature Conservation Act (1978).

8.2.3 Ministry of Agriculture

With respect to fisheries, this Ministry is concerned with the control of research into diseases of freshwater fish with these activities directed by the Veterinary Services (see section 8.3.3) through the Communicable Fish Diseases Control Act (1987).

8.3 Scientific and Research Services

8.3.1 The Ministry of Fisheries directs the following organizations:

1. Danish Institute for Fisheries and Marine Research, which has: (a) an Inland Fisheries Laboratory, which conducts research on freshwater and diadromous fisheries and advises the Ministry and the public; (b) a Trout Culture Research Station (see section 8.4); (c) a Physiological Laboratory; and (d) an Ichthyopathological Laboratory.

2. Technological Laboratory (fish processing, etc.)

3. Bureau of Fisheries Statistics.

8.3.2 The Ministry of Environmental Protection directs a Freshwater Laboratory of the National Agency of Environmental Protection, which is concerned with investigation of ecological problems with respect to inland waters, including fishing waters, and advice to local authorities.

8.3.3 The Ministry of Agriculture's Veterinary Services direct: (i) a Department of Infectious Fish Diseases concerned with disease control and health certification of live fish and fish eggs; and (ii) a State Veterinary Serum Laboratory for research on fish disease.

8.3.4 Other governmental bodies concerned with studies affecting inland fisheries include the: (i) Freshwater Biological Laboratory of the University of Copenhagen, and the (ii) Botanical Institute of the University of Arhus.

8.4 Non-Governmental Bodies concerned with the inland fisheries of Denmark include: (i) Union of Danish Anglers' Associations, (ii) Danish Society for Freshwater Fisheries (mostly commercial interests, pond farmers, commercial fishermen, riparian owners), (iii) Association of Danish Trout Pond Farmers, (iv) Danish Trout Pond Farmer's Experimental Station, which is associated with the Trout Culture Research Station (section 8.3.1), (v) County Water Inspectorates, (vi) Water Quality Research Institute of the Danish Academy of Technical Sciences, (vii) Danish Aquaculture Institute of the Danish Academy for Technical Sciences, (viii) Sewage Committee of the institution of Danish Civil Engineers, and (ix) various local associations interested in angling and commercial fishing.

8.5 Management

8.5.1 Legislative Authority

The Danish Government makes the laws regulating fisheries in both marine and inland waters with respect to: ownership, protection (seasons, size limits, etc.), passage of diadromous fish, etc. Additional local regulations can be secured if approved by the Ministry of Fisheries.

8.5.2 Licensing and Revenue

There is no general fishing licence in Denmark. The commercial fishery in lakes is normally carried on under lease contracts. Angling in Danish territorial waters is free. Anyone can fish freely for sport in Danish inland waters if he pays the owner of the water for fishing rights. Local licences can be purchased from the owner, renters of the rights, or from the manager of a public water.

One way in which funds may be used for improvement of fisheries in inland waters does, however, occur through use of the “Penalty Fund”, a committee to which all penalties incurred for violating the Inland Fisheries Act accrue. Such funds are earmarked for the improvement of fisheries through fish stocking, construction of fish passes, etc.

8.5.3 Operational Management

Danish fishery laws are administered by the Ministry of Fisheries. The management and development of individual fishing waters - whether exploited commercially or for sport - are not, however, in the hands of any public agency except in the case of State-owned waters. The individual fishery manager has no obligation to follow the advice given by the Ministry except in cases where State subsidies are involved, e.g., trout liberation schemes.

Management of most State-owned lakes is in the hands of the local forestry districts. Many of these waters are used commercially and/or for sport on lease contracts, and the lessees may have to follow certain management practices.

Any manager or owner of an inland fishery, public or private, may obtain professional advice from the Inland Fisheries Laboratory. Advice for public waters is free; private interests must pay for field surveys.

Stocking of trout in rivers and coastal waters may be carried on by private enterprises under the control of Fishery Control officers. Local clubs can manage trout liberation schemes, buying fish from commercial fish farms, or in some cases securing eggs by stripping wild fish. They may also aid the fisheries through elimination of competitors, such as pike, under permission of the Ministry of Fisheries.

8.6 International Agreements

Denmark has a bilateral agreement with the Federal Republic of Germany concerning uses of their boundary streams.

¹ This section is derived from Gaudet (1974), material received by EIFAC from Denmark in 1979, Dahl (1982), and Denmark/EIFAC (1989)

9. STATE OF THE FISHERY

9.1 Yield

The fish production in seven small streams in Denmark containing primarily salmonoid populations was calculated by Mortensen (1977) as ranging from 4.7 to 27.4 g/m²/year (equivalent to 47–274 kg/ha/year). In another small Danish stream, he calculated a production of from 6.3 to 12.8 g/m²/year (63 to 128 kg/ha/year) of Salmo trutta (Mortensen, 1982). Another study in a small Danish stream recorded a production of about 9 g wet weight/m²/year (90 kg/ha/year) for European eel compared with the production of salmonids in Danish streams, stated by the authors Rasmussen and Therkildsen (1979), to be about 5–40 g wet weight/m²/year (50–400 kg/ha/year).

Actual yield to the fisherman is, of course, far less. With respect to static water fisheries, the commercial fishing catches for 1973, shown in Table 7, represent the returns from only the 22 782 ha of lakes and 999 ha of reservoirs from which catch statistics were reported. The yield from these lakes was, therefore, about 21 kg/ha/year, that from reservoirs 60 kg/ha/year. This commercial lake yield is identical with that recorded by Nielsen (1977) for Denmark's largest lake, Arresø, in 1974 (Table 11).

The potentiality of the lake is illustrated by the fact that in 1971, the bream catch alone was 140 145 kg, a yield of 34.5 kg/ha/year.

Table 11

Commercial catch and yield in Lake Arresø, 1974

With respect to non-commercial catch, those statistics shown in Table 9 represent returns from only 5 426 ha of lakes and 200 ha of reservoirs. The yield to the fisherman from these lakes was, therefore, 4.3 kg/ha/year, that from the reservoirs 20 kg/ha/year.

With respect to overall catches in Denmark's inland waters, it has already been pointed out (section 7) that the statistics - at least as reported by FAO in its Yearbook of Fishery Statistics -leave much to be desired. Although neither Table 5 nor Table 8 indicate that the commercial catch in inland water (trout not included) is declining, Denmark/EIFAC (1970) states that it is indeed decreasing (see sections 9.2 and 9.3).

The yield of cultivated trout from Danish fish farms has had a high average with respect to the quantity of water used. It required only about 5 litres/sec (range, 1.7 to 8.3 litres/sec) of water for each ton of annual production (Alabaster, 1982a).

Again, and despite any misgivings concerning its accuracy, the trend of trout production through cultivation is reasonably correct in Table 5. The table indicates some ups and downs between 1965 and 1978 with the highest production (19 100 t) in 1968 dropping to only 9 300 t in 1970, recovering to 15 000 t by 1972, and rising to over 20 000 t during the next fifteen years. Fish disease problems, markets, and other factors have influenced this production. For example, in 1969 there were no trout exports from Denmark to the U.S.A. in order to control fish disease, especially myxosomiasis. Restrictions on import of trout have also been made by Canada.

9.2 Factors Affecting the Fishery

Denmark's small size, limited amount of surface water (conditioned as it is by rainfall and dispersion over its fragmented areas) plus intensive demands upon its water courses, keep down the yield from its inland fisheries.

Although the low gradient and small flow of the streams have protected them from hydroelectric development (harmful to streams in many other countries), these same attributes have lessened their value for fisheries. None of the streams are large. They are slow-moving and thus susceptible to pollution. The cool climate makes the streams suitable for salmonoid fishes, but being sandy and muddy they lack good spawning areas for these fish. Although there are few natural falls, man-made barriers have created deterrents to migratory fish.

There are a fair number of lakes and ponds, but most are small and all are shallow. Few have remained oligotrophic, and the majority are becoming increasingly eutrophic with winter fish kills not uncommon. Pike-perch, a species adaptable to turbid waters, is becoming a more dominant part of the lake fisheries.

Drainage, straightening, culverting and canalization have reduced fish habitat. Heavy land and water use from agriculture and urbanization has increased both siltation and water pollution with subsequent fish mortality. Fortunately for the inland waters, most major towns and industries are located in coastal areas but there is localized pollution from these sources.

The low annual runoff per caput of only about 2 148 m³ annually cannot provide much water dilution of effluents; Denmark is very deficient in this regard.

In addition to the built-in land and water uses, drainage of some areas, aided by Government subsidies, has had an adverse effect on inland fisheries; circa 1969 about 10 000 he were drained annually. This land reclamation has destroyed spawning grounds, caused discharge of acid bog waters into streams, and weirs constructed to decrease erosion have formed barriers to migrating fish. Barriers to fish migration are not, however, new in Denmark. Weirs at mills on some streams have prevented spawning since the Middle Ages.

In addition to the unfavourable environmental factors, commercial capture fisheries may decrease because of increased working expenses and low price received for the catch-especially that for cyprinids. In Lake Arresø, for example, commercially caught bream have of late been fed to the more valuable eels in the lake (Nielsen, 1977).

Aside from these factors, a very important determiner of the progress of inland fisheries in Denmark has been the much greater (quite logically) emphasis, both governmentally and industrially, on commercial marine fisheries. No spot in Denmark is more than 52 km from the sea. Production of fish from salt water is easily available, and there has been no dependence on inland fisheries for fresh supply. Governmental concern with the commercial aspects of fisheries has also lessened its interest in developing sport fisheries (cf. France).

With respect to aquaculture, Denmark had an early lead on its competitors in the field (most of its output is destined for export) because of the conditions described in section 7.2. Trout culture has been handicapped, however, by relatively slow growing conditions (including a necessity to overwinter the fish without much growth), which require about 14 to 28 months to produce a marketable product. The use and re-use of surface waters (because of absence of springs) sometimes by closely sited farms has also aggravated fish disease problems. Furthermore, the use of trash fish for feed (which produces more waste than pellets), heavy concentration of fish farms, and the use of relatively little water, have all contributed to a decline in water quality which has brought about restrictions on the establishment and enlargement of fish farms under the Danish Environmental Act. Thus, for example, the use of trash fish for feeding was prohibited from use in fish farms in 1985.

The loss of export markets, e.g., to Italy and North America is also a factor in diminishing the growth of Danish trout farms.

9.3 Prospect

As no large storage of water is possible in Denmark, and dependence on ground water sources are already extremely high, the outlook for increased freshwater fishery area is slight. On the contrary, suitable water areas will be further diminished despite efforts under the Conservation of Nature Act to diminish changes in water quality or hydrology (e.g., changes in water level) which might affect aquatic life adversely.

Demand for the low-value stocks such as cyprinids is already low and will diminish further. Little increase in inland fish production through capture fisheries can, therefore, be foreseen, and attention here will be turned toward the production of high-value fish such as eels. The Danish Aquaculture Institute (DAI) has estimated that by 1990, some 3 000 t of eels could be produced annually in Denmark from recirculation systems plus power station cooling water (Wray, 1986).

Trout culture, given Denmark's large experience, established position in the industry and vigorous policy for its development, can be expected to increase in value, but it now has heavy competition in Europe with both French and Italian trout farms. It must, therefore, be conducted under much more rigorous conditions than heretofore, and the industry cannot further develop its increasingly limited fresh water using its old extensive methods. Most of the suitable freshwater areas (almost all in Jutland) are now in use. It will require intensive methods such as greater stocking densities, employment of fast-growing strains, aeration, and re-use of water, all conditioned by the necessity to keep effluent discharge within tolerable limits. It has been noted (section 6) that the Danish Pollution Council has predicted a demand in the year 2000 for only one-half the amount of water used for Danish fish farms in 1970. If the prediction is correct and production is still to continue at its present level, it is obvious that major changes will be needed.

Edwards (1978) felt that Danish trout production would stabilize at about 15 000 t annually. Pino and Kirk (1982) also felt that Denmark's freshwater potential for trout cultivation was only about 15 000 t annually and sea water production about 3 000 t, and Brown (1983) felt that Danish trout production had peaked. But Denmark's production has already far surpassed all these prophescies. Moreover, in addition to its fresh waters, it has been estimated that about 220 000 ha of estuarine waters in Denmark are suitable for trout culture. Perhaps expansion will occur here, especially in conjunction with the use of cooling water from power plants. In fact, Anon. (1986) has prophesized that Denmark would double its farmed fish production to about 50 000 t in the next 10 years.

The rise of sport fishing, as in most European countries, will continue. It has already surpassed the yield of commercial fisheries in Danish rivers, will undoubtedly increase in lacustrine waters and provide a most valuable recreational resource to this heavily populated country. Coarse fishing, previously rather neglected by Danes, is increasing in popularity.

10. REFERENCES SPECIFIC TO DENMARK

Andersen, F.O. and E. Lastein, 1981 Sedimentation and resuspension in shallow eutrophic Lake Arreskov, Denmark. Verh.Int.Ver.Theor.Angew.Limnol., 21:425–30

Andersen, T., 1977 Danish legislation on the use and protection of freshwater areas. In Danish limnology. Reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:125–9

Dahl, J., 1976 Report of national activities concerning EIFAC for the period 1974–1976. Country report for the 9th Session of EIFAC, 1976:6 p. (Unpubl.)

Dahl, J., 1978 Denmark. In Reports from EIFAC member countries, Biennium, 1976–78 (Meeting paper) Rome, FAO, EIFAC/78/Inf.7:13–8 (mimeo)

Dahl, J., 1982 Denmark country review. In Allocation of fishery resources. Proceedings of the Technical Consultation on Allocation of Fishery resources held in Vichy, France, 20–23 April 1980, edited by J.H. Grover. FAO/American Fisheries Society, pp. 556–61

Dahl, J., 1982a Denmark. In Country reports of EIFAC member countries for inter-sessional period 1980–82, edited by K. Tiews. (Meeting paper). Rome, FAO, EIFAC XII/82/16:9–10 (mimeo)

Dahl, J., 1984 Country report 1982–84. Denmark. In National reports for the inter-sessional period 1982–84/Rapports nationaux pour la periode inter-sessions 1982–84, edited by the EIFAC Secretariat/edites par le CECPI Secretariat. (Meeting paper). Rome, FAO, EIFAC/XIII/84/Inf.4:1–10 (mimeo)

Dahl, J., 1984a A century of pikeperch in Denmark. EIFAC Tech.Pap./Doc.Tech.CECPI, (42), Supp.1. Vol. 2:344–52

Dahl, J., 1986 Denmark, In National reports of EIFAC member countries for the period January 1984 – December 1985, edited by European Inland Fisheries Advisory Commission. EIFAC Occ.Pap./Doc.Occas.CECPI, (16):5–11

Dahl, J., 1988 Country report, 1986–87, Denmark. In National reports of EIFAC member countries for the period January 1986 – December 1987, edited by European Inland Fisheries Advisory Commission. EIFAC Occ.Pap./Doc.Occas.CECPI, (20):15–21

Danmarks Statistik, 1988 Statistical yearbook. Argang 92/Volume 92. København, 518 p.

Danmarks Statistik, 1989 Statistisk arbog 1989. Argang 93/Volume 93, København, 516 p.

Denmark, 1978 Government of, Monograph on the water supply in Denmark. In Water development and management. Proceedings of the United Nations Water Conference, Mar del Plata, Argentina, March 1977, edited by A.K. Biswas. Oxford, Pergamon Press, Vol. 4, p. 2516

Denmark/EIFAC, 1970 Country report on inland fishery activities in Denmark, 1970. (Prepared for the 6th Session of EIFAC, 1970, by the EIFAC Correspondent.) (Unpubl.)

Denmark/EIFAC, 1974 Information on inland water fisheries production in Denmark. (Response to a questionnaire, EIFAC/74/Circ.10, Nov. 1974). (Unpubl.)

Denmark/EIFAC, 1977 Information on inland water fisheries in Denmark. (Response to the EIFAC Secretariat) (Unpubl.)

Denmark/EIFAC, 1989 Information on inland water fisheries in Denmark. (Response to the EIFAC Secretariat) (Unpubl.)

FAO, 1986 Denmark. FAO Fishery Country Profile. Rome, FAO, FID/CP/DEN Rev.2:4 p.

Fish Farming International, 1984 Two big Danish firms develop eel farming. Fish Farming Int., 11(2):7

Fish Farming International, 1984a Sea farming takes off on Danish Coast. Fish Farming Int., 11(5):4

From, J., 1979 Mass rearing of fry and fingerlings of trout species (Salmo spp.). EIFAC Tech.Pap., (35) Suppl.1:126–31

Great Britain, 1944 Naval Intelligence Division, Denmark. London, H.M. Stationery Office, Cambridge University Press, Geographical handbook series, BR 509 (Restricted): 611 p.

Hansen, I.W., 1979 Operation clean-up. Fish Farming Int., 6(2):32–4

Jensen, V.B. and K.I. Dahl-Madsen, 1978 Nitrogen fixation and denitrification in some Danish lakes. Verh.Int.Ver.Theor.Angew.Limnol., 20:2217–21

Jonasson, P.M., 1977 Lake Esrom research 1867–1977. In Danish limnology. Reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:67–89

Jonasson, P.M., 1984 The ecosystem of eutrophic Lake Esrom. In Ecosystems of the world 23. Lakes and reservoirs, edited by F.B. Taub, Amsterdam, Elsevier Science Publisheres B.V., pp. 177–204

Jorgensen, O.H., 1982 Legislative measures concerning trout farming in Denmark. EIFAC Tech.Pap., (41):137–40

Kristiansen, J., 1977 A survey of the investigation of freshwater phytoplankton. In Danish limnology. reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:37–44

Larsen, K., 1955 Fish population analysis in some small Danish trout streams by means of D.C. electrofishing. Medd.Dan.Fisk.-Havunders.(Ny Ser.), 1 (10):1–69

Markmann, P.N., 1984 Introduction of grass carp (Ctenopharyngodon idella Val.) into Denmark. EIFAC Tech.Pap./Doc.Tech.CECPI, (42), Vol.2 Supp.:325–34

Mortensen, E., 1977 Fish production in small Danish streams. In Danish limnology: reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:21–6

Mortensen, E., 1982 Production of trout, Salmo trutta, in a Danish stream. Environ.Biol.Fish., 7(4):349–56

Muus, B., 1960 The influence of drainage work and reclamation on stocks in Danish estuarine waters. In IUCN, Seventh Technical Meeting. Athens, September 1958. Soil and water conservation. Vol. 4. Natural aquatic resources. Brussels, IUCN, pp. 265–70

Muus, B., 1967 The fauna of Danish estuaries and lagoons. Distribution and ecology of dominating species in the shallow reaches of the mesohaline zone. Medd.Dan.Fisk.Havunders.(Ny Serv.), 5(1):316 p.

Nielsen, E., 1977 The development of the fishery in Lake Arresø with special reference to the bream population (Abramis brama L.). In Danish limnology: reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:27–35

Ovesen, C.H., 1977 Conservation of water areas in Denmark. In Danish limnology: reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:131–6

Rasmussen, E., 1977 Danish brackish-water fauna - 200 years research. In Danish limnology: reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:91–100

Rasmussen, G., 1984 Liberation of trout (Salmo trutta L.) in Danish streams. EIFAC Tech.Pap./Doc.Tech.CECPI, (42), Supp.Vol.1:164–77

Rasmussen, G. and B. Therkildsen, 1979 Food, growth and production of Anguilla anguilla L. in a small Danish stream. Rapp.P.-V.Reun.CIEM, 174:32–40

Riemann, B. and H. Mathiesen, 1977 Danish research into phytoplankton primary production. In Danish limnology: reviews and perspectives, edited by C. Hunding. Folia Limnol.Scand., 17:49–54

Rying, B, (ed.), 1974 Denmark: an official handbook. Copenhagen, Press and Cultural Relations Department, Royal Danish Ministry of Foreign Affairs, 902 p.

Warrer-Hansen, I., 1982 Evaluation of matter discharged from trout farming in Denmark. EIFAC Tech.Pap., (41):57–63

Water Quality Institute, 1978 Undersøgelse of Simested Å, 1977. Rapport til Nordjyllands Amt. Horsholm, Denmark, Water Quality Institute, 94 p.

Wray, T., 1986 Denmark se es big future in eels. Fish Far.Inter., 13(2):20

Anon., 1986 Aquaculture in Denmark. Power plant trout should be profitable. Fish Farm.Inter., 13(1):12