New study rings louder death knell for tuna
Three Simon Fraser University biologists, including two co-authors of a new study, say that the study’s findings on the fate of tuna globally intensify a conundrum in managing this dwindling species.
Do regional fisheries management organizations (RFMOs) risk making multi-million dollar fisheries go bankrupt by putting a moratorium on them? Or do they continue to allow fisheries to drive tuna into extinction to make money now and pay later environmentally?
Along with bonitos, mackerels, Spanish mackerels and billfishes such as swordfish and marlins, tunas are members of the Scombrids family.
For the first time fishery scientists, biologists and conservationists have jointly rated the vulnerability of 61 known species of scombrids. Another first, their rating is based on the International Union of Conservation of Nature’s (IUCN’s) categories for evaluating risk of extinction. The IUCN is the world’s main authority on the conservation status of species.
The study puts five of eight species of tuna globally in the threatened or near threatened IUCN Red List Categories, meaning the species are at serious risk of extinction.
Southern Bluefish tuna are the most threatened – critically endangered Atlantic Bluefin (T. thynnus) are next, a fishery worth $10 million annually to Canada. The rating corresponds with an endangered rating on the species by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in May 2011.
SFU biologists Nick Dulvy and this study’s co-authors Lucy Harrison and Maria José Juan Jordá research scombrids and shark species on the IUCN Red List and are involved in the organization’s conservation efforts.
They note that the latest study, just published in Science, reinforces that fishing of Southern and Atlantic Bluefin tuna stocks needs to be dialed down until the species recover to avoid their total collapse.
SFU scientists on new IUCN Red List study
Of the 61 known scombrids rated on the IUCN Red List of Threatened Species, seven are classified in a threatened category, being at serious risk of extinction. Four species are listed as Near Threatened and nearly two-thirds have been placed in the Least Concern category.
The results show that the situation is particularly serious for tunas.
Dulvy, Harrison and Jordá admit that shutting down tuna fisheries would create substantial economic hardship and inevitably foster illegal fishing, making it hard for RFMOs to safeguard the targeted species.
Jordá, an IUCN Tuna and Billfish Specialist Group member preparing a doctoral thesis co-supervised by Dulvy, says, “Reducing fishing efforts to safe levels sounds surprisingly simple.
But tuna management is challenging because many different countries and multiple fisheries with different interests exploit these species. This makes their management incredibly difficult and often ineffective.”
Adds Dulvy, co-chair of the IUCN Shark Specialist Group, “This study confirms that high seas fisheries can be managed sustainably with sufficient political willpower. It makes economic sense to bring back these species from the brink of extinction and recover them to the point where they can yield less risky profits in the future.”
Harrison, an SFU biology grad now working as the IUCN Shark Specialist Group’s program officer, says: “Climate change is driving Atlantic Bluefin tuna north into Canadian waters. This gives Canada the opportunity to fish them but we are also responsible for protecting this resource. The Ministry of Fisheries and Oceans has an opportunity to secure a future for Atlantic Bluefin tuna and tuna fishers by listing this species under the Species at Risk Act in Canada.”
- Copies of the new Science paper High Value and Long-Lived: Double Jeopardy for Tuna and Billfishes may be obtained from the AAAS Office of Public Programs. Please contact +1.202.326.6440 or scipack@aaas.org.
