A comparison of the IUCN Red Lists of 1996 and 2007 show a considerable rise in the number of threatened fish species, a lecturer at a recent FishBase symposium in Stockholm said.
Dr. Rainer Froese, FishBase coordinator at the University of Kiel, said there had been a 77 per cent increase in the total of those three categories that comprise the “threatened” group – “Vulnerable” (70 per cent), “Endangered” (96) and “Critical” (78). A total of 1,127 species were categorized as threatened now.
The most threatened orders were the seven species of swordfish (100 per cent of them). Sturgeons, as well as sharks and rays were other orders for which the situation had worsened considerably – in the latter case because of higher demand of and prices on their fins.
Dr. Froese pointed out, however, that there may be an unknown bias to the material, since many more species were assessed in 2007 than in 1996. The 2007 analysis was based on 9 per cent of the 30,967 fish species in FishBase, for the 1996 Red List 3 per cent were assessed.
A total of 3.6 per cent of those assessed now were categorized as threatened, the situation worse for freshwater species – 6.1 per cent of those were threatened.
These are some other of the findings in Dr. Froese’s comparison:
- There is a trend that the later a species is discovered, the higher the threat. This suggests that some species may become extinct before they are formally described.
- Freshwater fishes that are small or very large are the most threatened by extinction, especially if they occur in densely populated areas.
- Generally, large fishes are the most threatened, both in freshwater and saltwater.
- The threat is higher to species living in tropical or temperate areas.
- Fishes used by humans – fisheries, angling, aquariums – are more threatened now than in 1996, 5.4 per cent of the species in 2007, as compared to 3.2 in the earlier analysis.
- Studying migration patterns, anadromous fishes – e.g. salmon – are clearly more threatened than others.
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FOOTNOTE: IUCN = the International Union for Conservation of Nature