Rare and threatened - fish species

Rare and threatened species
Typography
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The Barents Sea region is inhabited by 28 fish species which are either on the Global Red List (8 species) or on the Norwegian Red List (25 species) (Table 4.3.6). Among these, 13 are data deficient (DD) species, i.e. the species would likely appear on the red list if adequate information were available. When considering the lists of rare and threatened marine fish species, 3 main groups of impact factors may be considered: 1) fisheries (catch and by-catch); 2) environmental

degradation (pollution, habitat destruction); and 3) effects of climatic change. Fisheries are believed to have the most important impact on red-listed species today; climatic changes may become equally or more important in the future, but less controllable (Table 4.3.6).

Among fish species on the Norwegian Red List which inhabit the actual area, 8 species are classified as threatened species (CR, EN, or VU). Of these, two species are classified as CR, critically endangered:

  • ICES consider all spiny dogfish/spurdog (Squalus acanthias) in the entire area stretching from the Barents Sea to the Bay of Biscay to belong to the same population. Catch statistics show a steady and marked decline from 1973 (≈ 33,000 tonnes) to 2003 (5,000 tonnes). Due to late maturity and low fecundity this species is very vulnerable to overfishing
  • The other critically endangered species on the Norwegian red list is the European eel (Anguilla anguilla). This anadromous species is not considered further here due to its marginal importance in the Barents Sea

Five species are classified as VU, vulnerable:

  • Porbeagles (Lamna nasus) have a long life expectancy and low reproductive ability; this species is very vulnerable to overfishing. Reported catches have decreased from over 1,000 tonnes in the 1960s to about 20 tonnes in 2002. ICES recommends no fishing of this species; it is assumed that it will take at least 25 years to rebuild the stock even with minimal catch rates
  • Blue ling (Molva dypterygia) occur in the entire area and are fished commercially. Norwegian catches have been reduced from more than 2,000 tonnes in 1960 to less than 500 tonnes in 2004. Fisheries directed at blue ling have been stopped and it is only taken as a by-catch in the ling fishery. The closely related common ling (Molva molva) is listed as near threatened (NT). After a severe decline in the past, this species now seem to be stabilizing or even increasing again in the northern part of its distribution area
  • Sebastes marinus and Sebastes mentella exists in the entire area and are fished commercially. Populations of both species have decreased considerably, probably due to overfishing. ICES considers both species to have reduced reproductive capacity; they therefore need protection to allow the stocks to rebuild
  • The lesser sand eel (Ammodytes marinus) is most important in the North Sea; they also occur along the coast of northern Norway and in the Barents Sea. This species is classified as VU on the red list mainly due to overfishing in the North Sea
  • Cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are on the international red list, but neither species is considered threatened in the Barents Sea. The populations of coastal cod along the northern Norwegian coast is, however, rated as critical (CR) because of ongoing population reduction, poor recruitment and lack of effective regulation

Table 4.3.6. Species on the 2010 Norwegian Red List considered threatened due to negative population trends by category: critically endangered; endangered; or vulnerable. From Meld.St.10 (2010-2011) —Norwegian Ministry of the Environment (NMD, 2012).

In addition to Molva molva mentioned above, Hippoglossus hippoglossus, Somniosus microcephalus, Theragra finnmarchica, and Trisopterus esmarkii are listed as near threatened (NT) on the Norwegian red list, and Chimaera monstrosa is listed as NT on the international red list. Among these species Trisopterus esmarkii and Chimera monstrosa are of minor importance in the Barents Sea.

The assessment of Hippoglossus hippoglossus as NT on the red list is based on trends in Norwegian catch statistics over the last 3 generations (45 years). North of 62oN the population has increased again during the last 10-year period; there recruitment seems to be good. Still halibut is considered threatened by overfishing due to its long reproduction period.

The once common Greenland shark (Somniosus microcephalus) population in the Northeast Atlantic is now very low; this species is rarely caught and registered. It is widespread in cold ocean waters in the northern hemisphere, but its biology is poorly understood. For reasons of its slow growth, late maturity, and low fecundity this species is listed as NT in Norway in accordance to the precautionary principle (IUCN, 2015).

Fewer than 60 individuals of Norway pollock (Theragra finnmarchica), which according to resent studies may be a substock of Alaska pollock (T. chalcogramma), are known from 16 localities, all (with one exception) in the Norwegian sector, particularly outside the Tana fjord. All individuals have so far only been large specimens, most of them ready for spawning or having spawned.

 
 
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