VALUABLE AREAS FOR COD, HADDOCK, HERRING AND CAPELIN IN THE LOFOTEN - BARENTS SEA AREA.

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1 VALUABLE AREAS FOR COD, HADDOCK, HERRING AND CAPELIN IN THE LOFOTEN - BARENTS SEA AREA. Asgeir Aglen Harald Gjøsæter Jens Christian Holst Jarle Klungsøyr Erik Olsen Institute of Marine Research February

2 BACKGROUND This report was written by the Institute of Marine Research in February 2005, as an assignment for WWF- Norway. The report is based on the best available knowledge regarding the life cycle and biology of cod, haddock, Norwegian spring-spawning herring and capelin in the area of Lofoten and up to the Barents Sea. INTRODUCTION The geographical restrictions in this report are, roughly speaking, the equivalent of the area under research as defined for the future Barents Sea Integrated Management Plan. (The Norwegian Ministry of Environment leads this process and it is estimated to be completed in 2006.) This area is shown in Figure 1, and the westerly and southerly borders especially, have been used to restrict the scope of areas to those relevant for the Lofoten-Barents Sea area. The easterly and northern borders for the management plan have not been adhered to, as the Barents Sea has it s own natural borders from a biological and oceanographic point of view, consisting of Novaya Semlja in the east and the ice edge in the north. Figure 1: Study area for the future overall management plan for the Barents Sea. The report provides a description of the areas for spawning, egg, larvae, nursing and feeding for the four species. The most valuable areas for all these species will be the areas that have the greatest significance for reproduction and stock growth. If these areas are threatened or destroyed, the most serious consequences could be that the existence of these species might be threatened. For all of these species, these will be areas where large numbers of the population and/or a year class are gathered together at the same time

3 In other words, the spawning, egg and larvae areas for these species. All four species have in common that they make use of large sea areas during their life cycle, through large-scale migration between spawning and feeding areas. The migrations are typically seasonal, and an area that is significant during one period of the year, may be almost empty of fish during other periods. Therefore, we have chosen to present the valuable areas for each species on a quarterly basis, as this allows comparison between the species and shows seasonal variations as well as life cycle. A GENERAL NOTE ON THE VULNERABILITY OF FISH WITH REGARD TO THE PETROLEUM INDUSTRY There is no simple or overall description of how the petroleum industry affects fish. The industry is responsible for sudden and acute oil spills which result in large and small oil slicks, and operational spillage from drilling and production. In the oil industry s report on spillage from oil and gas production on Norwegian platforms in 2003, the total acute oil spillage consisted of 877 m3, most of which came from a single oil spill from the oilfield named Draugen. The typical picture is, however, a number of smaller spills that are spread over time and space in areas with offshore petroleum operations. There are additional oil spills from shipping traffic. It is not usual that environmental studies are carried out in connection with the smaller acute oil spills. The effects of the large acute oil spills are investigated when they occur. In the Barents Sea, there have been no such episodes in recent years. Studies from spills in other areas document that sea birds smeared with oil as well as other large-scale negative effects on the seashore fauna. Reported effects on fish are normally limited to examinations of oil components in fish found just under or in the vicinity of the oil slick, and this can negatively affect the quality of the fish by changing it s taste, something which can in turn have a depreciative market value for fish sales from areas where such spills have occurred. However, fish have the ability to precipitate the oil components within a few weeks in cleaner seawater. Very few field studies have managed to document biological damage to fish as a result of being exposed to oil. It should be emphasised that the methods available for carrying out such studies are inadequate. Results from laboratory experiments show, however, that damage does occur when the level of exposure is high enough. The most important condition for serious impact on fish and other marine organisms is, naturally enough, the degree of overlap in time and space between the oil spill and the resources. Organisms which have fewer possibilities for active movements, such as plankton, fish eggs and fish larvae, are probably most vulnerable. During the egg and larval stages, fish are most concentrated over the smallest geographical area, and this, in addition to the lack of ability to move around by themselves, makes the eggs and larvae most vulnerable to exposure to oil in the sea. To make observations regarding the risk of damage to fish fry, models describing movement, spreading and breakdown of oil from an oil slick can be put together with models showing the distribution of fry and then a risk picture can be drawn. In the (Utredning av helårig petroleumsvirksomhet i området Lofoten Barentshavet), environmental assessment of year-around petroleum exploration in the area from Lofoten to the Barents Sea, (Norwegian Ministry of Oil and Energy, 2003), it has been shown via a model that during a long-lasting oil spill in an area, the consequences can be a loss of cod eggs of over 25%, and a loss of herring larvae of over 20%. It is assumed that larger fish can avoid the oil spill by - 3 -

4 simply swimming away from the area. The models show that the probability of damages to whole year classes of fish stocks in the Barents Sea are very small, even in the event of larger oil spills. CAPELIN Stocks of capelin in the Barents Sea remain within the area inside the borders for this study; and this means that all life stages of this fish can be found there at any time. Capelin undertake seasonal migrations. The exact distribution area will vary from year to year, and is first and foremost decided by the climatic conditions and the size of the population. The distribution maps in this document which describe the different life stages per quarter describe a normal situation. It can generally be said that when the population grows, it s distribution will expand, especially in the feeding season. The expansion occurs especially towards the north and east, and in this way, a smaller population of fish will have it s feeding area further towards the south and the west than a larger population. A warmer climate will, in the same way, make the feeding areas expand towards the north and the east. The spawning areas will also be affected by the spawning stock s size as well as the climate, but there is no real clear connection between distribution and climate/population in the spawning period, as can be seen during the feeding period. Westerly and easterly spawning can, respectively, occur in both cold and warm years, and when the population is small and large. The spawning areas must therefore be decided by other, more complex conditions than climate/fish stocks alone. This description covers the different life stages through the different seasons and also deals with both horizontal and vertical distribution. The capelin has an extremely short life cycle, which distinguishes it from all other fish species in the Barents Sea. The capelin spawns only once, and maturity is decided by it s weight rather than age. This means that when capelin grow quickly, the majority will be only three or four years old when they spawn, whilst in periods of slow growth, many can be five and sometimes six years before they breed and die. Capelin also differs from most other fish species in the Barents Sea due to the fact that it lays eggs on the seabed, where the eggs remain until they hatch. The time from spawning to hatching varies greatly depending on the temperature. With a typical temperature of 4 C in the breeding areas, 50% of the eggs will have hatched after approximately 40 days, and all of the eggs will have hatched within about 2 months. Breeding usually begins around the middle of March and can go on into April. Spawning also occurs in the summer, but this is limited to areas east of Vardø and the scope of this breeding is usually insignificant compared to the main breeding season. The egg stage Spawning of eggs usually takes place from mid-march and into April, with an incubation period of approximately one month. The eggs will therefore be on the seabed from the middle of March until the beginning of May. This stage is included in the diagram for the first and second quarter. The eggs have a sticky substance on the egg membrane and are stuck to the substrata, which is usually coarse sand, gravel or shingle. The westerly breeding areas have more recently been around Andenes, and the easterly border is normally assumed to be the Kolafjord. Spawning has been described in older Russian literature as having taken place as far east as Novaja Zemlja, but it is uncertain if this referred to a local population that bred in this area. In 1992, there were reliable observations of spawning around the island of Dolgiy, south of Novaja Zemlja. Spawning from a depth of approximately 10 to 150 metres is described in these observations, but spawning normally occurs at a depth of 20 to 60 metres, near land. There is only limited spawning inside the fjords, as the majority of the spawning areas are out along the coast, and preferably areas with a strong current

5 The larval stage Strictly speaking, the larval stage lasts per definition until metamorphosis begins, and in the case of capelin, this can take place well into summer of the second year, when the fish is between 7 and 9 cm in length. During metamorphosis, the pigmentation changes from the so-called glass capelin, which is more or less transparent, to pigmentation similar to the adult. Scales are also formed during this period. Normally, we use the term larvae for a much shorter period, from hatching, when the larvae are approximately 7-9 millimetres until well into the late summer, when they are millimetres. Capelin larvae are then referred to as the 0-group (zero-group) for the rest of their first year. The larval stage is therefore included in the maps for the second and third quarters. During this period, the larvae are transported by the ocean currents, and distribution will therefore reflect both which breeding areas they come from and the strength of the currents. Larvae from spawning areas west of the Tromsø shelf will normally be transported outwards by the arm of the North Atlantic current which goes along the edge of the continental shelf in the direction of the west coast of Svalbard. The larvae which hatch further to the east will be transported north and eastwards towards the central and easterly areas of the Barents Sea south of 73 N. The larvae can be found from the surface of the water down to m deep, but most are to be found at a depth of between 10 and 60 m. In the first phase after hatching, the majority of the larvae will be in the upper 25 m, but after a while most of them will be found deeper down. The 0 group stage is included in the maps for the third and fourth quarters. During this stage the larvae become more able to move by themselves, and they can actively swim to change both their vertical and horizontal distribution. At this stage, the larvae which were transported out towards the westerly areas are transported up along the western coast of Svalbard and can be found as far north as 80 N in the late autumn. Those which were transported into the Barents Sea expand their distribution towards the east and the north and can have a distribution that practically covers the whole of the Barents Sea in the autumn if the year group is numerous, or the eastern part of the sea if the year group is small. Depth distribution is from the surface and down to metres. Young Capelin After the larvae have survived the first winter, the term young capelin is used, and this stage lasts until they mature in the autumn of their second, third, fourth or fifth year. The young capelin stage can last several years and it is mainly during this stage that active seasonal migrations take place. This stage is therefore drawn in on the maps for all quarters. In the late autumn, those inside the area to the north will migrate southwards as the ice shelf grows in the northern Barents Sea, and they will spend the winter south of the ice shelf, which generally follows the polar front. In the summer and autumn the young capelin will move around vertically during the day, spread out over the top 100 m during the night and gathered together in shoals at greater depths during the day. With the onset of the shorter arctic nights in the autumn, the capelin will generally be found in deep water and mostly near the seabed day and night. When the days become longer and lighter in the spring, the young capelin will begin to move vertically during the day. In some years, it will migrate southwards from their winter areas to the coastal banks where the plankton production starts in spring. During the summer they will embark upon a migration north and eastwards as the ice recedes. This is also connected with the continuous biological production that takes place at the edge of the ice, and that moves northwards during the summer. The young capelin will be located in their most northern areas at the beginning of the fourth quarter. Maturing - mature Capelin The adult stage begins in the third quarter when the capelin is cm long, and lasts until it spawns and dies the following winter. This stage only lasts about half a year and is included on the maps for the - 5 -

6 fourth and first quarters. The largest capelin, i.e. the ones that mature first, will most likely be the ones furthest north. The southern migration from the northern feeding areas to the winter areas are common for young and maturing capelin, and these stages spend the winter in the same areas in December to January. Towards the end of January maturing capelin start to separate from young capelin and move in towards the coasts to spawn. Breeding migration can take many routes in to the coast. There is an annual easterly drift that gathers far to the east at Gåsbanken to then migrate west along the coast of The Kola peninsula, and further westwards along the coast of Finnmark, to eventually reach the coast of Troms where the population stays to spawn. Drifting can also occur more centrally towards the coast of Eastern Finnmark or to the west towards West Finnmark or Nord Troms. The male capelin will generally die straight after breeding, while the females can survive for some time and gather in shoals near the breeding areas. Cod feed intensively on capelin during the drift towards the coast, during and after breeding, so that even if some capelin can survive breeding, very few, if any, will be likely to leave the coast and join the young capelin to maybe live another year and breed for a second time

7 . Figure 2: Quarterly distribution of the different life stages of capelin in the Lofoten-Barents Sea area. The breeding areas overlap completely with the egg areas, as capelin spawn on the seabed and the eggs remain in the substrata in the breeding area - 7 -

8 HADDOCK Northeast Arctic haddock are also prevalent in the coastal areas south of the area identified as a boundary for this study, but are not included on any of the maps. Haddock between 62 and 67 N are partially dealt with as a separate management unit. No clear biological criteria have been documented for such a separation. There are also important breeding areas along the edge of the continental shelf outside Møre og Romsdal. Spawning Northeast Arctic haddock breed in April to May in deep water ( m seabed depth) along the edge of the continental shelf. The most important spawning area is the western edge of the Tromsø shelf. Other important breeding areas are the edge of the continental shelf outside Røstbanken and Vesterålsbankene and outer Vestfjord (and along the edge of the continental shelf outside Møre og Romsdal). Eggs and Larvae The vertical distribution of haddock eggs has not been well mapped. Newly spawned eggs from the most northern breeding area are registered as being rather concentrated along the edge of the continental shelf (500m depth), and here the transportation of the eggs seems to be in a mostly northern direction for newly spawned eggs. The distribution of larvae also shows that there is a significant easterly transportation of larvae and probably eggs. Even if the haddock has a rather different breeding time and areas from cod, there is a significant overlap in the distribution of larvae for the two populations. Growth Areas The distribution of the 0 group in the autumn is similar to the distribution of the 0 group of cod, but does not normally stretch so far north and east. Haddock go down to the seabed in the autumn and remain in somewhat warmer water than cod (preferably over +1 C). The 1 group circulates normally in a more southerly area than the 1 group of cod. Important growth areas for 2-4-year-old haddock are the coast of Kola, Grey Zone (Disputed area between Russian and Norwegian Economic Zone) and the coast of eastern Finnmark. In certain years there are more young fish near the coast and 1-2-year-olds are more numerous along the majority of the coast of Troms and Finnmark. Vertical Distribution As for cod, the vertical distribution of haddock varies greatly according to the season and the time of day, but haddock remain mostly on the seabed after moving down. 1-2-year-old fish stay mainly at the bottom during the light seasons. In the dark seasons, it can be found spread out upwards in the water column, especially at night. The older fish have a more variable vertical distribution, but as a rule are more pelagic during the day than at night. During the late summer in eastern Finnmark there are large haddock closer to the surface of the sea day and night

9 Figure 3: Quarterly distribution of the different life stages of haddock in the Lofoten-Barents Sea area. Haddock spawn pelagic and the eggs are therefore spread out in open waters after spawning

10 NORWEGIAN SPRING-SPAWNING HERRING /NVG General Description Norwegian spring-spawning herring (NSH/NVG) is potentially the greatest population of herring in the ocean areas around Norway. The stock is a typically far-migrating pelagic population that makes use of large areas of the ocean for feeding during the summer, whilst it is stationary during the winter. It has a close connection with the Barents Sea and bordering sea areas. The connection with the Barents Sea is especially associated with the younger life stages (<3-4 years of age) and to a certain extent older fish that spend the winter there. NSH /NVG breed along the Norwegian coast in February-March. Spawning has been observed from east of Lindesnes and northwards, at least to Malangsgrunnen, with periodical variations. The most central and stable breeding areas seem to be from Stadt and northwards towards Buagrunnen. However, both southerly and northerly areas have also been important breeding areas for periods of time. For example, Røstbanken seems to be an important breeding area for NSH/NVG for the time being. After spawning in March, the adult fish move north and westwards towards the feeding areas in the Norwegian Sea. In May, the population is spread out over a significant sea area. When population levels are high, the stocks make use of larger areas between the Norwegian coast, Jan Mayen, Svalbard and Bjørnøya as feeding areas, but when stocks are low, feeding is limited to areas close to the Norwegian coastline. This was observed in the 1970s and 80s, after the drastic reduction of the population during the late 1960s. After spreading out over large areas during the feeding period, the population gathers together in August and begins the migration towards the areas where they spend the winter. As of 2002, the most important winter area for this fish has been out along the edge (seabed>500m) from Andenes and northwards towards 72 north. In the period from approximately 1989, the winter areas for NSH/NVG have been Vestjorden, Tysfjord and Ofotfjorden, whilst in the period from 1970 to the end of the 1980s they were fjords in Nordmøre and in Lofoten. The winter areas are therefore variable and appear to be connected with year groups. These herring migrate from their winter areas in January to the breeding areas and close the yearly cycle. The eggs are laid on the seabed. After hatching, the larvae are transported northwards along the Norwegian coast. Large year-groups are typically distributed with >95% in the Barents Sea and the rest in fjords along the Norwegian coast. Vertical distribution of herring is associated with the upper layers of water and the surface. This applies especially for the youngest life stages, which remain mostly in the uppermost 30 metres of the water. Relations to the Barents Sea The egg stage Spawning takes place at Røstbanken and northwards towards Malangsgrunnen. The eggs are laid on the seabed and the eggs hatch where they are laid

11 Larvae and the 0 group Larvae and the 0 group from the breeding areas along the Norwegian coast drift into the Barents Sea from early summer and are very abundant in the southerly areas of the area during the summer (see Figure 4). During the autumn, the 0 group of herring are distributed over large areas of the southern Barents Sea over towards the far eastern area of Novaja Zemlja. Most of the herring spend the winter of their first year in the same areas, at the southern end of the Barents Sea. Young herring As one-year-olds, the herring in the Barents Sea begin an annual rhythm of northern feeding migration and spending the winter in the south. (Figure 4). At the same time, a westerly shift takes place so that the youngest herring can be found in the east, while the older ones can be found further to the west in the Barents Sea. The annual north/south migration continues until the herring is approximately 20 cm, when the young herring migrate out of the Barents Sea. This migration depends on size, so that year classes with slow growth levels will, on average, be older when they leave the Barents Sea than year classes with quick growth levels. This means that the typical age for leaving the Barents Sea can vary from 3-6 years. This migration takes place in the spring and in May the year groups which have left the Barents Sea will be found in the sea northwest of Vesterålen. Adult Herring Compared with the young herring, the adults have a more marginal connection with the Barents Sea. No NSH/NVG are to be found in the Barents Sea itself, however, since around 1973, the adult herring has spent the winter in areas that are adjacent to the Barents Sea. In the 1970s and 80s the important wintering areas were in Lofoten towards Svolvær (Hølla, Austnesfjorden). Much of the herring fishery, to the extent that it was in operation during this period, took place in this area. At the end of the 1980 s, when the large 1983 year class appeared, the stock changed their wintering area to Ofotfjorden and Tysfjord. This then became the most important wintering area and the most important fishing area (Figure 4). This was the situation until around 1996, when new large year-classes appeared and led to a great increase in the size of the population. The stock now additionally used large areas of the inner Vestfjord as wintering areas. At the most, over 10 million tons spent the winter in the Vestfjord. The next change came when the 1998 and 1999 year classes left the Barents Sea in 2001 and It was expected that these year classes would spend the winter in the Vestfjord, like the older herring. This, however, did not happen and the young herring established a new wintering area from Vesterålen and northwards along the edge towards 72 north (Figure 4). This is a bordering area between the Barents Sea and the Norwegian Sea. So far, this area is assumed to be stable and can become the most important wintering area for herring for many years to come

12 Figure 4: Quarterly distribution of the different life stages of herring in the Lofoten-Barents Sea area. The breeding areas overlap completely with the egg areas as herring spawn on the seabed and the eggs remain in the substrata in the breeding area

13 COD The description includes both Northeast arctic cod and Norwegian coastal cod, but the maps show only Northeast arctic cod. Coastal cod is excluded from the maps as the knowledge of the stock belonging of eggs, larvae and 0-groups in fjords and coastal areas are limited. It is assumed that at least in the outer parts of the coastal areas, the younger stages of cod are dominated by the Northeast arctic stock. N Northeast Arctic Cod In some particular years, limited spawning takes place south of the area covered by this study, but in all other life stages, the whole population of Northeast arctic cod is within the covered area. Spawning areas Mature Northeast Arctic cod, ready for spawning are often referred to as spring cod. The most important breeding area is the shallow coastal banks from Malangsgrunnen to Røstbanken, as well as Vestfjorden from Skrova to Røst. Some spawning also takes place in Lopphavet-Breiviksbotn, and during years with a high sea temperature, spawning can also occur further east along the coast of Finnmark. More widely spread spawning can take place in significantly larger areas, and also in the Barents Sea. Cod has pelagic spawning and the eggs are left at various depths, usually deeper than 100m. The cod spawns in batches and some individuals can take over a month from laying the first batch until laying it s last. The majority of the spawning takes place in March-April, with the highest level of intensity around the beginning of the new month. Eggs The newly spawned eggs rise upwards in the water column and will be distributed in the upper 15-20m in calm weather, but are easily swirled downwards to considerably greater depths when affected by waves and currents. The eggs are spread horizontally with the currents, mostly in northerly and easterly directions. In a typical year, eggs will be found in the whole area from Røstbanken to the North Cape and northwards towards Bjørnøya. The greatest concentrations are often on the banks outside Troms. Larvae After hatching, horizontal spreading continues, but the greatest concentrations are still (in June) on the banks outside Troms and on the Tromsø shelf. The metamorphosis from larvae to 0 group takes place during the summer, and in August-September the 0 group is distributed over most of the Barents Sea south of the polar front, as well as along the coast of West Spitsbergen. The 0 group go down to live on the seabed in the late autumn. This means that it goes from a purely pelagic life in the uppermost 50-60m of the water column to a more seabottom-based life. Growth areas The cod year classes are normally most widely distributed from the late autumn as a 0 group until the late autumn as a 1 group. In this period concentrations can be found along the polar front, even in sea temperatures of around 0.5 C. The east-west distribution of year classes varies somewhat from year to year. The main quantity of the horizontal distribution will generally move southwest as the fish become older. 1-3-year-old fish have the smallest amount of seasonal migration, whilst the older fish feed at the polar front in the second half of the year and migrate south to breed as well as to feed in the first half of the year. 2-3-years-old fish have more or less the same distribution as the 1-group, but remain more around the warmer side of the polar front. Important growth areas for these age groups are the southeastern Barents

14 Sea, Grey zone and the Bear Island area. In the southwestern Barents Sea, there are normally very few 1-3- years-old cod. At the age of 3-4 years, capelin becomes a more important part of the cod s diet. A part of the cod population follows the capelin s breeding migration in February-March to the coast of the Kola peninsula and Finnmark, and in some years as far west as Troms. This applies to a greater extent for older fish until sexual maturity is reached at the age of 78 years, when they move to the breeding areas instead of remaining where the capelin are very abundant. Vertical distribution The vertical distribution varies greatly with the season and the time of day, but the cod remains mainly on the seabed after settling from the more pelagic life stage. 1-2-years-old fish stays at the bottom of the sea in the lighter season, and at least where the seabed is shallower than 300m. In the darker season, it can also be found spread upwards in the water column, especially at night. The vertical distribution of the older fish is more variable and can, periodically, be more pelagic at day time than during the night. Coastal Cod Coastal cod are regarded as a complex mixture of components from several different stock components, where the overlap and exchange between local components have not been well mapped. It is practical to distinguish between fjord cod (the typical fjord populations) and bank cod (the coastal cod which spawn further out). Both fjord and bank cod can also be found south of the area covered by this study. The management unit of Norwegian coastal cod covers these population components as far south as 62 N. Breeding Areas There has been evidence of fjord cod breeding in most fjords in Troms and Finnmark. Most of these breeding grounds are connected with the deep basins inside the fjords. Important breeding areas for bank cod are eastern Lofoten (Stamsund-Skrova) and at Breivikbotn on the western side of Sørøya. Bank cod have breeding grounds that partially overlap with spring cod, but the tendency is that bank cod spawn closer to land than spring cod. Coastal cod spawn a little later than spring cod, but the two overlap much in time. Spawning can take place in some fjords as late as June. Eggs and larvae Coastal cod eggs also drift upwards after spawning. Measurements have shown that coastal cod eggs are a little heavier than spring cod eggs and therefore are distributed a little deeper, and this can be significant for transport and horizontal distribution. The distribution and transport of bank cod larvae and eggs have not been mapped, but stream-simulations show a small difference in vertical distribution and breeding ground. This can possibly mean that the eggs and larvae of the bank cod remain closer to the coast than the eggs and larvae of spring cod. Growth areas Studies of the 0 group in fjords in Troms show that the 0 group of fjord cod like to move down to the bottom of the sea in shallow areas, right up to the shore area, whilst the 0 group of Northeast Arctic cod in the same fjord move down to the bottom of the sea in the deepest areas. It is assumed that the 0 group of bank cod move down to the seabed close to the coast and in rather shallow waters, and that it remains in these areas while growing. From the age of 2 years, both fjord and bank cod are distributed out in deeper waters. Studies of tagged adult fish show that fjord cod are mainly stationary within the fjords. In the open Finnmark fjords, some of the fjord cod migrate outside the fjord in the autumn, but return back during the breeding season. Bank cod seem to undertake greater migrations, both along the coast and up and down the edge of the continental shelf

15 Figure 5: Quarterly distribution of the different life stages of cod in the Lofoten-Barents Sea area. Cod has pelagic spawning and the eggs are then spread out in open water from the breeding grounds

16 CONCLUSION AND VALUE ASSESSMENT Cod, herring, capelin and haddock are the most economic and ecologic important fish species in the Barents Sea.. All species move in towards the coast of Nordland, Troms and Finnmark in order to breed in the first and second quarters of the year. During the spawning period, large proportions of the adult population gather within a limited geographical area to lay eggs in the pelagic waters (cod and haddock) or on the seabed (capelin and herring). The eggs are the production potential for the population that year, and as the eggs and larvae do not have the ability to move by themselves, they are extremely dependent on the physical, chemical and biological conditions in the environment around them to be able to survive to become fry. Incidents that might have a negative effect on the environment in which the eggs and larvae grow, can affect large numbers of the year classes of fish, even if the incident is of only a local or a regional character. Throughout the larval period, and later, as fry, a year class spreads itself out over large areas and this, in addition to the fry s ability to move by itself, means that any potential negative incidents on a local or regional basis will not be able to affect the whole year class. Based on an assessment of the life cycle of the different species of fish and how important an area is for it s biological production, it is possible to conclude that the most important areas for cod, herring, capelin and haddock are the breeding areas and the areas in which eggs and larvae of these species are to be found. These are the stages during which the fish are gathered together in a limited area and are most vulnerable to the effects of the physical, chemical and biological environment. Figure 6 shows a composite picture of all the breeding, egg and larvae areas imposed on each other. This covers both the 1 st and 2 nd quarters for the breeding and egg areas, whilst the breeding period stretches from the beginning of February (herring) to May (haddock). The distribution of larvae for the four species stretches through the 2 nd and 3 rd quarters. These are the areas that are to be regarded as the most valuable for cod, herring, haddock and capelin in the Barents Sea. As for the spawning and egg areas, the whole coast of northern Norway from Røst, including the inner side of Lofoten, to the Varanger peninsula is the most valuable area. With regard to larvae, the most valuable areas are larger in size, and cover the coast from Andøya to the Varanger peninsula, but also stretch outwards to the sea and include the Tromsø shelf and parts of the North Cape bank. The area from Lofoten to the Tromsø shelf can be regarded as the breeding ground for Norway s ecologically and economically most important fish stocks. This was the main argument for the Institute of Marine Research advising against all forms of off-shore petroleum operations within this area. This statement came in the process around the environmental assessment of year-around petroleum exploration in the area from Lofoten to the Barents Sea (Norwegian Ministry of Oil and Energy, 2003)

17 Figure 6: The most valuable areas for cod, haddock, herring and capelin in the Lofoten-Barents Sea area. The diagram is a composite picture of egg and spawning areas (left) and larvae areas (right) for the four species. The degree of the colour red reflects the extent of overlap between the species: the light red areas indicate a small degree of overlap while the dark red areas indicate a greater degree of overlap. With regard to time, the diagrams cover the breeding areas in the 1 st and 2 nd quarters (February to May), while the larvae areas stretch from the 2 nd to the 3 rd quarter