The Kingdom of Sweden, the third largest country in Western Europe, shares the Scandinavian Peninsula with Norway. Sloping generally east toward the Baltic coastal plain, its terrain ranges from frozen tundra and ice-clad mountains in the north to farmland in the south. Almost 60 percent of the country is forested, and almost 9 percent is occupied by inland waters: swift rivers in the north, smaller and slower streams in the south, and almost 100 000 lakes, of which four constitute a fourth of the lake area.
In addition to mining and forestry, Sweden is primarily an industrial nation. However, with most of its population concentrated in the south, large areas remain thinly populated and in relatively untouched state. Hydroelectric development has, nevertheless, had severe effects on the anadromous salmonoid fisheries, placing dependence upon heavy stocking to maintain them. Growing problems of pollution, including that by acid rain, affect all the inland fisheries.
Marine fisheries are minor in Sweden, and its commercial fishing for inland fishes is practised primarily in its Great Lakes and the brackish Baltic Sea. Aquaculture for trout is a minor industry. The proportion of sport fishermen to total population is one of the highest in Europe. With concentration on percids, pike and salmonids, recreational fishing has already surpassed the inland commercial fishery in importance.
|1.||AREA:||486 661 km2 1|
1 This figure for total area taken from Sveriges Officiella Statistik (1983, 1984 and 1989) differs from those given in most standard references (such as the Unesco Statistical Yearbook 1984) which agree or are generally close to the 449 964 km2 listed in Sveriges Officiella Statistik (1990) as total area, and the land and inland water area listed in Sveriges Officiella Statistik (1983, 1984 and 1989). The Swedish Consulate General's office in New York (comm. of 21 June 1983) states that on 1 July 1979 the territorial waters of Sweden were changed from 4 to 12 nautical miles, thus accounting for the difference in total area given in the newer Swedish statistical abstracts. As will be seen in section 5, such a change, particularly inclusion of marine territorial waters in the reported area of a country may change one's calculation of the extent of inland waters decidedly
|2.||POPULATION:||8 305 000 (1990)||Density: 18 inh/km2|
Sweden, which shares the Scandinavian Peninsula with Norway, lies between 55°20' and 69°4'N latitudes and 10°58' and 24°10'E longitudes. Fifteen percent of the country is above the Arctic Circle. Its extreme length is 1 574 km, and its greatest breadth is 499 km. Its altitudinal range is from sea level to 2 111 m, with a mean elevation of about 300 m.
It is bounded on the northeast by Finland for 586 km, and by Norway on the northwest and west for 1 619 km2. Its moderately indented territorial coastline, bounded by the Skagerrak and Kattegat to the southwest and by the Baltic Sea and its northern arm, the Gulf of Bothnia, to the east, and including the islands of Gotland and Öland, totals 2 862 km in length. The shore itself measures 7 264 km, and if one were to include all the little indentations, it could be said to total 14 000 km in length.
2 These boundaries are taken from Sveriges Officiella Statistik (1990)
Sweden has three territorial regions. Norrland, the great northern region, occupies 55 percent of the country. Central Svealand occupies 20 percent, and southern Götaland 25 percent. It can also be described as having four major physical divisions:
the northern mountain and lake region district which also includes a relatively level forested moraine, marsh and bog belt, and a region of sandy and clayey coastal plains incised by rivers;
the lowlands (mean elevation 300 m) or lake depression of central Sweden, arable, fertile, and dominated by great lakes;
the Smaland highlands in the south and southeast, mantled with sandy and gravelly till, forested, and with peat bogs.
the plains of Skane in the extreme south, part of the Great European Plain. With lime-rich fertile soil, it is largely agricultural.
Norrland, occupying over half of Sweden (from about 60°N to the northern boundary), slopes from the summit of the “Kjölen” Mountains, along the Norway frontier, east and southeasterly to the Baltic coastal plain in a series of steps crossed by parallel rivers in deeply cut valleys. These rivers, which rise in mountains exceeding 1 500 m in height, are linked with long narrow high level lakes formed mostly by moraines.
The down-faulted lowlands of central Sweden, although interrupted by blocks of higher land, are generally low. In the detached highland area of Smaland, the general elevation exceeds 100 m and there are some areas over 350 m.
The natural vegetation ranges from Arctic-Alpine types (e.g., mosses, lichens and dwarf birch) in the north and in the high mountains, through coniferous forests (especially spruce and Scots pine) over most of the country, to some deciduous forest (oak-beech) in the south. About 60 percent of the entire country is forested, and of this, about 85 percent is coniferous.
About three-quarters of Sweden forms part of the Pre-Cambrian Baltic shield mostly of gneisses and granites, making its waters particularly vulnerable to acid rain (see section 9.2). Soil types vary in response to the bedrock and to an uneven cover of glacial drift, marine deposits and alluvium. Generally speaking, especially in the north, soil is thin and acid and often absent.
The coast is partly rocky, fringed with hundreds of little islands or skerries. In places the coast is indented by broad “fjärds” cut by preglacial streams but widened out and without steep sides.
In addition to the mainland and small islands, Sweden has two large islands off its east coast: Gotland (3 001 km2) and Öland (1 344 km2).
The overall climate is cold temperate. Warmed by Atlantic winds it has higher temperatures than its latitude would suggest but the maritime influence is reduced by the high mountains on its western border.
In the north, the winters last about seven months and summers less than three; in the south, winters are less than two months long and summers over four. Near the extreme north (70°N) there may be about 73 days of continuous daylight but the winters are dark. In the south, mid-summer days last 17 hours, winter days 6.5 hours.
In northern Sweden, the mean annual temperature is -2.7°C, the mean monthly range is -14.6°C to 12.2°C. At Lund (extreme south), the mean annual temperature is 7.2°C, the mean monthly range is 0.5°C to 16.6°C.
The growing season in Sweden (i.e., the average period with air temperatures above 3°C) ranges from about 250 to 90 days from south to north. In the Swedish central lowlands it is about 190–210 days.
The average annual precipitation for the entire country is about 700 mm, varying from about 500 mm in the southeast to 2 000 mm in the northwest mountains. The maximum rainfall is in July and August. Early spring is the season of least precipitation but it is also a period of thaw, melt-water and river flooding. Much precipitation is in the form of snow, from 9 percent in the extreme south to 36 percent in the far north. Snow cover varies between about 50 days (south) to 200 days (north), and the snowline varies from 1 335 to 880 m in the far north.
Ice cover on the lakes averages 90 days in southern Sweden, 150 days in central Sweden and over 200 days in the north1. Owing to high latitude and low salinity, the northern part of the Gulf of Bothnia may be frozen from 110 to 210 days of the year.
1 The great lakes of Vättern, Mälaren and Hjälmaren have an ice-cover during December–April
The mean evaporative rate is about 300 mm (450-150 mm).
5. HYDROGRAPHY AND LIMNOLOGY
The total area of inland water in Sweden as given in or calculated from data in numerous publications throughout the 1957–88 period, ranges from about 30 017 to 40 477 km2, or roughly from 6.8 to 8.9 percent of the country's total area as given in the same publications2. When such calculations have been made by the author, he has simply subtracted “land area” from “total area” to achieve a remainder representing “inland water area”. (This is the same method outlined in the FAO Production Yearbook.) It is obvious, however, that if Sweden's Statistical Abstract (Statistisk årsbok för Sverige) includes territorial marine waters in its “total area” (see section 1) that such a calculation cannot be made for this country using only such data. Otherwise, without any increase in “land area” (said to be 411 615 km2 in both the 1978 and 1982/83 Swedish Abstracts) the inland water area would have leaped from 38 349 km2 in 1978 to 75 046 km2 in 1982/83 or from 8.5 to 15.4 percent of “total area”. In 1983 it was suggested to the Government that a country's statistics on land and water areas would be clearer were they presented as follows: total area, land (meaning non-water) area, territorial marine water area, inland (fresh and in some cases brackish) water area. The Statistical Abstracts for 1984 (published 1983) and 1985 (published 1984) and subsequent editions do make this clear in saying that Sweden's land and inland water area is 449 964 km2 as the inland water area. This is 8.5 percent of the strictly continental area. Meanwhile, one concludes that the inland waters of Sweden total about 40 000 km2 or - as the Swedish Institute (1981) puts it - “Some 100 000 lakes cover more than 38 000 km2 … or about one-eleventh of the land area, i.e., six times the lake density of the world continents.” Willén (1984) expresses it this way: “In Sweden there are about 100 000 lakes occupying nearly 9 percent of the total land area”.
2 Some of the difficulties encountered in this paper in obtaining accurate information from respected but secondary sources are shown by the following examples concerning the area or percentage of inland water in Sweden. O'Dell (1957) says that 8 percent of Sweden is Inland water. Bergsten (1961) says that lakes cover 8.5 percent of the total area. Worldmark (1971) says that the total area is 449 749 km2 of which the land area is 402 279 km2 and the water area 40 477 km2 including rivers and some 96 000 lakes. But, five years later, Worldmark (1976) increased the total area to 449 964 km2, and the land area to 411 407 km2 and reduced the water area to 38 557 km2 or 8.6 percent. And in 1988 (Worldmark, 1988), it further reduced the inland water area to 38 349 km2 or 8.5 percent of the total area (given as 449 964 km2) including some 96 000 lakes. Meanwhile, the Encyclopaedia Britannica (1974), claiming to use “official” governmental figures, gives the total area as 449 750 km2, land area as 411 479 km2 and inland water area as 38 271 km2. Hanson (1978) says that Swedish lakes alone cover 40 000 km2. FAO (1988), the source of Table 6, probably using figures obtained from Sweden, indicates a total area of 449 996 km2, a land area of 411 620 km2 and a calculated inland water area of 38 040 km2 or 8.5 percent of total area. Europa (1985), citing Statistics Sweden as its source, gives the total area of Sweden as 448 661 km2 and its extent of inland water as 37 155 km2 or 8.3 percent of the country, but Europa (1988), citing the same source, presents the following relevant figures: 440 945 km2 total area, and extent of inland waters 30 017 km2, or 6.8 percent of total area
The areas of the major drainage basins of Sweden are shown in Table 1.
Major drainage basins of Sweden
|Basin||Total area km2||Area inside Sweden km2|
|Vänern - Göta älv||50 200||42 800|
|Torneälven||40 200||25 300|
|Ångermanälven||31 900||30 400|
|Dalälven||29 000||27 900|
|Umeälven||26 700||26 500|
|Indalsälven||26 700||24 700|
|Luleälven||25 200||24 500|
|Mälaren - Norrström||22 600||-|
|Vättern - Motala ström||15 500||-|
|Helge å||4 780||-|
Source: Statistisk årsbok för Sverige, 1990
The drainage pattern in Sweden is greatly influenced by the general inclination of the land surface of the northern and central parts, i.e., the land slopes toward the east and southeast from the “Kjölen” Mountains where the largest rivers have their sources.
The approximate annual runoff in Sweden is 400 mm or 180 000 million m3. Upstream countries contribute 3 000 million m3, so the total annual river discharge leaving the country is 183 000 million m3 (Van der Leeden, 1975; ECE, 1978).
5.1 Rivers (Floder, Älv)
The total length of Sweden's rivers is about 60 000 km. There are ten rivers with lengths of over 400 km and 27 in all which are longer than 100 km. Table 2 lists the major rivers of Sweden and their lengths.
Principal rivers of Swedena
|River||Total length km||Length inside Sweden km|
|Klarälven - Gotä älv||720||520|
|Muonioälven - Torneälven||570||-|
|Järpströmmen - Indalsälven||420||-|
|Toftaån - Lagan||270||-|
a The Klarälven flows southerly out of Norway (where it is known as the Trysilelva) to enter Lake Vänern which is drained to the Kattegat (Atlantic) by the Gotä älv. The Muonioälven-Torneälven, which flows generally south to the Gulf of Bothnia, forms part of the Swedish/Finnish boundary. Below it, and proceeding to the Gulf of Bothnia/Baltic, from north to south in this order are the following: Kalixälven, Luleälven, Piteälven, Skellefteälven, Umeälven, Angermanälven, Indalsälven, Ljungan, Ljusnan, Dalälven and Emän. The Toftaån-Lagan and Ätran are tributary to the Kattegat
Source: Statistisk årsbok för Sverige, 1990
The discharge of seven of Sweden's principal rivers is shown in Table 3.
Discharge of seven major Swedish rivers. Mean monthly discharge, m3/sec
|Vänern Göta älv||Muonioälven Torneälven||Dalälven||Umeälven||Luleälven||Ångermanälven||Indalsälven|
|Period of record||1938–66||ca 1969||ca 1969||ca 1969||1941–66||1954–66||ca 1969|
|Regulated station||Vänersborg||-||-||-||Boden works||Sollefteå||-|
Source: Vänern-Göta älv, Luleälven and ångermanälven from Van der Leeden (1975). Others from Framji and Mahajan (1969)
There are four major types of Swedish rivers, their characteristics generally linked with their latitudinal and altitudinal positions.
Mountain rivers. With a great store of snow and ice, their low winter flow is transformed with snowmelt into a prolonged spring flood. The great variations in flow have required much regulation in order to use these rivers for hydroelectric production. Examples are the Luleälven with a mean annual flow of about 510 m3/sec (mean range, 82–1 910 m3/sec) and the Daläven with a mean annual flow of 370 m (mean range, 95–1 150 m3sec). The principal mountain rivers of the Norrland slopes are linked to long narrow lakes and flow swiftly southeasterly toward the Gulf of Bothnia over many falls and cataracts. Few falls are found in the fjäll or upland area. Most are found in the middle or lower reaches, and there is a definite falls line (so-called Glint line) in the lower course of the northern rivers above the flat coastal land. Both the steep slope and the bare rock characteristic of most of these drainages contribute to the rapid runoff. However, the lakes aid materially in holding back the total flow.
Central lowland streams. These small rivers have a short spring flood and a rapid run-off over a long plain. An example is the Nyköpisån with a mean annual flow of 23 m3/sec (mean range, 9–55 m3 /sec).
South Swedish highland streams. With smaller snowpack, there is a less marked spring flood and the major run-off is during autumn, the wettest season. Examples are the Ätran (west side of Sweden) with a mean annual flow of 50 m3/sec (range, 12–165 m3/sec), and Emån (east side) with a mean flow of 30 m3/sec (range, 7–100 m3/sec).
Outlets of large lakes. These usually have a very uniform run-off, being stabilized by the lake. An example is the Göta älv with a mean annual flow of 575 m3/sec (mean range, 510–660 m3/sec).
Domination of both length and volume is clearly evident in the characteristics of Sweden's northern mountain rivers. The maximum flow in at least six of these exceeds 1 700 m3/sec. By contrast, many small rivers of southern Sweden have low flows, and some are sluggish and silty. Minimum flow in many of these is almost zero.
5.2 Lakes (Sjöar)
Like its northern neighbours, Sweden has a large number of natural lakes, estimated variously as from 96 000 to 100 000 in number, and from about 38 340 km2 to 40 000 km2 in total area. Using the largest round numbers, there are about 100 000 lakes with a total area of 40 000 km2 and total estimated volume of 600 000 million m3 (Hanson, 1978). Table 4 lists the names and areas of Sweden's largest lakes.
The four largest lakes (see below) take up about one-fourth of the entire lake area. A further 4 000 lakes are larger than one km2; the remainder, accounting for about 20 percent of the total lake area, are smaller.
Most of the many mountain lakes are narrow “string” or “finger” lakes, lying close to the same elevation (300–400 m), and formed by moraines. Some of these lakes are over 160 km in length, but most are only 5–6 km in width. Although they help contain the swift flow of the rivers, flow-through in the northern lakes is very rapid and their productivity is also lessened by the prevailing bare and acid terrain.
Principal lakes of Sweden
|Storsjön i Jämtland||456|
|Siljan with Insjön and Orsasjön||354|
|Stora Le and Foxen||131|
Source: Statistisk årsbok för Sverige, 1990
The most extensive lake area is in the central lowlands which contains Sweden's four largest lakes: the tectonic-glacial Vänern, 5 585 km2, 140 km long and 75 km wide; Vättern, a graben lake, 1 912 km2 in area, 130 km long and 31 km wide; Mälaren, once a bay of the Baltic and now a series of basins with narrow sounds, 1 140 km2 in area, 115 km long and 66 km wide; and Hjälmaren, 484 km2 in area, 60 km long and 20 km wide. Among the largest lakes in Europe (exclusive of the former USSR), Vänern ranks as the largest and Vättern as the second largest. Of these four lakes, only Vättern is still completely oligotrophic. Vänern although still oligotrophic is on its way to a mesotrophic state and the others are on the eutrophic side. Other characteristics of these lakes as well as of the Baltic Sea - which provides considerable fishing for freshwater fishes - are shown in Table 5, and catches in the four largest lakes in Sweden are shown in Table 14.
There are also hundreds of lakes in the lowlands. Many of these, especially in the southwest, are turning into peat bogs and have a low productivity.
There is thus a range in waters - from the highly oligotrophic waters of the north, through the eutrophic waters of the lower, more settled regions, to dystrophic waters in the Smäland highlands.
Characteristics of the four largest lakes in Sweden and the Baltic Sea
|Parameter||Unit||Lake Vänern||Lake Vättern||Lake Mälaren||Lake Hjälmaren||Baltic Sea|
|Area||km2||5 585||1 912||1 140||484||372 730a|
|Basin area||km2||46 830||4 447||21 483||4 053||1 649 550|
|Basin area in relation to lake volume||km2/km3||309||61||1 534||1 398||79|
|Population in the basin ca 1970||million||0.7||0.175||1.3||-||20|
|Annual load per year ca 1970|
a Excluding estuary area. With estuarial area: 415 125 km2 and 21 714 km3
Source: A composite based on (varying) data from: Milway (1970), Van der Leeden (1975) after Falkenmar, Swedish IHD Committee (1973), Falkenmark and Mikulski (1975), Rundberg (1977), Willén (1984), and Essvig (1990)
Owing to the prevailing bedrock of slowly weathering granite, gneisses and porphyries, the majority of the Swedish lakes have soft and low-buffered waters with a natural alkalinity of 0.1–0.2 mekv/1 or less and a pH of 6–71. There are, however, limestone or lime-rich areas in Sweden and here the water may have a bicarbonate content often of the order of 0.5–2 mekv/1. This natural state has, however, altered sharply in recent years, tending toward greater acidification (see section 9.2).
1 Dickson (1978) says that in remote mountain areas of Sweden there are still lakes with a conductivity of less than 1 m/Sm
Retention time in Swedish lakes varies from one to two years in most lakes to several decades in some.
5.3 Reservoirs (Reservoar/Konstgiorda bassinger/Sjöar)
Most of the larger lakes in northern Sweden have been impounded or regulated to further the production of hydroelectric power. For example, the regulation of Lake Hjälmaren at the end of the nineteenth century was the most extensive project of its kind in Sweden. In fact, the largest volume of water in Europe is stored in the reservoirs of Sweden and Spain. The dams raise the natural levels in summer and autumn and lower it below normal levels in winter and spring. Such drawdowns (e.g., to 35 m) affect the fishery adversely by decreasing the bottom fauna, altering spawning grounds, and otherwise affecting the fish stocks. Generally speaking, such changes have been more detrimental to trout (Salmo) than to chars (Salvelinus). Since 1976, efforts to improve reservoir fishing have included stocking with fish and food organisms, and improvement of biotopes.
5.4 Canals (Kanaler)
There are several major ship canals in Sweden, of which the Göta, completed in 1832, is the best known. This series of waterways with 58 locks connects Göteborg on the Kattegat to Stockholm on the Baltic, a distance of about 620 km. Mostly river and a series of lakes, only 82 km of the “canal” are artificial. The canal proper is 14 m wide and 3 m deep.
Most of the smaller Swedish canals have now been closed to traffic.
5.5 Coastal Areas
Although the salinity on the small west coast of Sweden is about 20 ppt, the salinity off the remainder of the Swedish coast, as with other areas of the brackish Baltic basin, is low. Ackefors (1986) considers that about 5 700 km of a 7 600-km coast is brackish. River runoff to the Baltic Sea amounts to about 1 000 mm yearly when averaged over the whole of the area. The Sea is characterized by a positive freshwater balance and its water is brackish. The eastern coast of Sweden lies along the Gulf of Bothnia (the northern part called the Bothnian Bay, the southern part the Bothnian Sea) and the main Basin of the Baltic. Its southern tip abuts on the western Baltic through which there is hydraulic contact with the North Sea over shallow threshholds in the Danish straits. Basically, the Baltic water mass consists of an upper layer with a continuous flowthrough of freshwater from the rivers discharging into the Baltic and a lower layer of water of higher salinity which is renewed in an oscillatory manner through irregular saline instrusions. Stagnant conditions may develop in some of the basins of the Baltic proper with oxygen exhaustion and formation of H2S the bottom water but the Gulf of Bothnia supports populations of both marine and freshwater fish. The salinity off the south coast of Sweden is about 11 ppt, and in the Baltic the range is between 10 and 7 ppt. The Gulf of Bothnia does not exceed 6 ppt and at its head drops to as low as 1 or 2 ppt. Freezing occurs in the Gulf as a consequence. (For other information on the Baltic, see Table 5 and also the review of Finland).
6. LAND AND WATER USE
The climate, poor soil, extensive forests and abundant hydroelectric and iron one resources (which have made industry paramount) have been the major determinants of Sweden's land and water use and distribution of its population - with their consequent effects on inland fisheries. Sweden is now considered about 84 percent urban and 16 percent rural, and 90 percent of its population is concentrated in the south, which is also the centre for agriculture and manufacturing.
Livestock raising is a large part of agricultural production. Hay leads all other field crops, using about one half the cultivated land, followed by oats, wheat, rye and potatoes. Only about 1.6 percent of the small cultivated area (0.11 percent of the entire country) is irrigated - mainly as drought insurance. Irrigation has, therefore, little effect on fisheries, using only about 50 million m3 annually or less than 0.03 percent of the total run-off. Extensive bog areas have, however, been drained for pasture and even some lake areas have been drained to increase farmland, e.g., 18 000 ha of Lake Hjälmaren. This drainage has had some effect on fisheries as has the heavy liming of soils, and the growing use of chemical fertilizers, which is still less, however, than the European average.
Pattern of land use in Sweden, 1987
|Arable and permanent crops||6.6|
|Forest and woodland||58.7|
Source: 1987 FAO Prod. Yearb., 47 (Publ. 1988)
The forests of Sweden and Finland are the largest in Europe. Sweden has the highest roundwood production in Europe (Finland is second) and is a very high producer of wood pulp and cellulose for export. Its pulp and paper companies are big vertically integrated businesses, which own a quarter of all the forests. Swedish streams have been used for many years to float timber during high water and such rafting has often been detrimental to salmonoid populations, in part through destruction of streambeds. Although some recent reports describe extremely high use of rivers for floating logs (e.g., Europa, 1974, reports 32 000 km of Swedish streams used to float timber rafts), the official Governmental statistics (Sveriges Officiella Statistik, 1978) say that the floatways in 1976 totalled 6 200 km of which only 3 147 km were used, and the amount of timber transported by truck in 1980 was 35 times that using floatways (Sveriges Officiella Statistik, 1982). Timber roads and all-year trucking are now replacing the use of rivers in Sweden as log carriers. The forest industries continue, however, to produce water pollution through release of waste fibres and liquors. More than 90 percent of the discharge of organic material into the Gulf of Bothnia comes from the forest industry (Bengtsson, 1982).
Sweden lacks almost any coal and oil, but has high-grade deposits of iron, zinc, and lead, and Western Europe's largest deposit of uranium - destined under its national plan for production of nuclear energy (see below).
Major industries, aside from mining and forest products such as wood pulp and paper, include iron and steel, precision equipment, food and motor vehicles. Industries use about 80 percent of Sweden's water, and contribute largely to its water pollution.
In addition to pollution from forestry products, major sources include mines, smelters, plating, textiles, beet sugar manufacture, dairies and milk products, and sewage. Circa 1971, 86 percent of the oxygen-consuming matter discharged to rivers and coastal waters in Sweden came from industry and 14 percent from sewage (Johnson and Brown, 1976). Most of the water pollution is concentrated along the coast and in the south. Public sewerage is increasing rapidly and, generally speaking, river pollution in Sweden is far below that of other heavily industrialized European nations (see section 9.2 concerning eutrophication and acidification).
Sweden has a very high use of electric power, and until recently most of this was hydroelectrical originating from Norrland's rivers. Most of this is low head power derived from streams having a long gradual descent of rapids rather than high falls. The earlier power stations were constructed at “steps” but as these sites were used up, dams and reservoirs were required to stabilize flows and create artificial heads. Thus, in addition to creating more barriers to fish migration, long areas of good spawning and feeding grounds were dried out or turned into deep basins of still water with severe implications for the fisheries. For these reasons, as well as the decision to turn to artificial propagation of Atlantic salmon and sea trout (see section 7), few fishways have been built lately and many old ones have been removed.
In 1987, the total installed electrical capacity in Sweden was 33 455 000 kW of which 50 percent (16 700 000 kW) was hydroelectric, 22 percent thermal, 28 percent nuclear, and 5 000 kW geothermal. Good hydroelectric development is almost complete. An excellent electrical grid system permits well dispersed industry, which, of course, increases the opportunities of more wide-spread water pollution.
Road density in Sweden is low, only about 0.5 km/km2, but passenger car ownership is one of the highest in Europe, 420 automobiles per 1 000 people (1989). There is a rail system of 12 323 km (1983). Although the rivers are rarely navigable, except for Göta älv in the south, the larger lakes are navigable except during the January-March period, and a canal system has modified the original drainage patterns of the south and opened Lakes Vänern and Mälaren to seagoing craft. In 1978, there were about 1 165 km of inland waterways, and some water pollution results from their use.
Flood control has also had an effect on the fisheries, e.g., a decrease in the pike (Esox lucius) fishery at Lake Mälaren has been attributed to reduced water levels during the spawning period (Rundberg, 1977).
The marine fishing industry is only a marginal sector in the highly industrialized Swedish economy. Most of the country faces on the brackish Baltic rather than on the more productive Atlantic side. With a marine catch in 1987 of 210 728 t, Sweden ranked 49th in total world fish catch. Inland commercial fisheries are of even lesser importance in Sweden, but both commercial and subsistence inland fishing are practised in Sweden and - as in Finland - some farmers make part of their living through fishing. For farming (where fish are used for food) is also a Swedish industry. Despite the relatively low production of fish caught commercially, fish is important in the Swedish diet, accounting for some 15 percent of animal protein and 10 percent of total protein supply. Import accounts for a substantial proportion of the total fish supply. Per caput fish consumption is high, about 29.4 kg/year.
Sweden has reasonably good groundwater sources, and its surface water supply is excellent. Domestic and industrial supply account for about two percent of the total precipitation. Fifty-five percent of urban water use is from the surface, and major industries use almost 100 percent surface water - the highest use being in the cellulose, paper, mining and metal industries. Circa 1974, it was estimated that 3.5 percent of the total national surface flow was required for cooling, and these requirements would increase to 80 percent by the year 2000.