Tunas are managed by the regional tuna fisheries management organizations (RFMOs) based on the best and most recent scientific recommendations made by their own scientific committees. We wonder if the IUCN Red List on tunas is scientifically consistent with the view of tuna scientists of the RFMOs. We asked Dr. Peter Makoto Miyake regarding the validity of IUCN’s decision. Dr. Miyake worked for a long time as the Assistant Executive Secretar y (the scientific coordinator) for the International Commission for the Conservation of Atlantic Tunas (ICCAT) and is now participating in various scientific committees and working groups of various tuna RFMOs as a Visiting Researcher at the National Research Institute of Far Seas Fisheries of Japan. He is one of the tuna scientists who have an extensive view on the latest status of tunas in the world.
Dr. Miyake stated:
“IUCN again issued ver y strange warnings. The organization, which had so far included tuna species, one after another, in its Red List, added the Atlantic bluefin tuna to the listing this time.Looking at its past histor y, IUCN had included even Eastern Pacific bigeye and yellowfin tuna in its Red List, regardless of the fact that scientists had agreed that the stock sizes of these species are above the maximum
sustainable yield (MSY) level and fishing mortality rates are below the MSY level, i.e. the stocks have not been overfished or no overfishing is taking place. Contrary to these scientific conclusions, IUCN is still keeping those species in the Red List, although on somewhat at lower levels.
Why does such a contradicting decision go unchallenged? It is probably because, at the IUCN, there are only few experts specializing in the fish population studies. Most of the member experts involved in such decisions are taxonomists or ecologists and can be more vulnerable to the influence of environmental groups. Furthermore, those experts had to base their judgments simply on the established criteria, routinely applying them to all animals. Their established criteria are the proportion of the current stock size relative to the initial population level.
Although the criteria are complicated, let’s see how they work with a simplified example. If a rare animal species, for which only 100 individuals exist on the earth, decreases to 50, then everyone would agree to protect them as an endangered species. However, if a tuna stock, say with one million fish in its initial status, decreased to a half million fish, then the stock is considered to be just at the right level of MSY, according to the population dynamics theory. According to the IUCN criteria, however, both cases represent the endangered status.
Many specialists on tuna population dynamics pay little attention to the conclusions based on such criteria. I am ver y concerned, that if IUCN continues to make its judgment based on such criteria, it would be not tunas
that may be in risk but the very authority and credibility of IUCN itself.
