Good Bluefin Science Calls For More

Courtesy of United Nations Food and Agriculture Organization Andrey Urcelayeta photo

Scientific research on bluefin tuna (BFT) has made significant progress in recent years. Until now, the understanding of this highly migratory fish had been limited to catch data – weight, length, where, when, etc. Decisions on the stock assessments and management in the Western and the Eastern Atlantic for years have been based not on sound science, but on erroneous information.

Compounding the problem of limited and inaccurate data has been the resistance of some in the scientific community to do anything that might upset the status quo for whatever varied reasons.

Two important findings that have come out of decades of research at the Large Pelagics Research Center (LPRC) in Gloucester, Mass., are the documented mixing of BFT from the Western and Eastern Atlantic and the Mediterranean and the verification of the lowered age of maturity of bluefin tuna.

The importance of these two findings to a greater understanding of these important fish and to the validity of stock assessments and, therefore, any effective management plan is widely recognized. Bluefin tuna scientists have long called for the best science and for not allowing the cherry picking of the science to further any agenda.

“Bluefin tuna is a complex species,” said Dr. Molly Lutcavage, Director, LPRC. It changes where it travels and what it eats. Bluefin is highly migratory, living and traveling between the Gulf of Mexico and the Eastern end of the Mediterranean Sea, said Lutcavage. When it was shown that there was a lot of mixing of the Eastern Atlantic and Mediterranean with West Atlantic BFT, there was resistance to this science for political, economic and status quo reasons. The absence of any real management structure in place in the Eastern Atlantic and Mediterranean was another factor. This enabled a free-for-all harvest plan there.

Knowing the age of maturity is essential to understanding fecundity and how that is contributing to the strength of the tuna stocks. This very recent science can dramatically change the accuracy of the stock assessments needed to manage the tuna stock. Formerly, it was thought that only the large, old bluefin tuna were sexually mature. This unfounded belief was used in the stock assessment over the last 20 years or more.

In a peer-reviewed paper published June 9, 2014, LPRC scientists wrote,

“Despite attention focused on the population status and rebuilding trajectory of Atlantic bluefin tuna (Thunnus thynnus), the reproduction and spawning biology remains poorly understood, especially in the NW Atlantic. At present, the eastern and western spawning populations are believed to exhibit different reproductive characteristics and, consequently, stock productivity. However, our study suggests that the two spawning populations, the Gulf of Mexico and the Mediterranean Sea, could show similar reproductive features and spawning strategies.

“The reproductive biology of Atlantic bluefin tuna (ABFT; Thunnus thynnus, L. 1758) remains poorly understood despite the high economic value of this fishery and its exploitation throughout the Atlantic Ocean and the Mediterranean Sea. These uncertainties directly affect our understanding of the recruitment and productivity of the stock and could result in inefficient management of the fishery.”*

Almost as mysterious as the lives of bluefin tuna is Pew Foundation criticism of the LPRC research. The Pew Foundation challenged the LPRC data, calling it unsupported, only to be rebutted by the LPRC with peer-reviewed recognition. “We've done this research since the 1990s. It is difficult to do, but we stuck with it. We are proud of our work,” said Lutcavage.

Chris Weiner harpooning blue fin tuna in the Gulf of Maine. Ben Weiner photo

The LPRC has been doing the pioneering research on bluefin tuna—a fish the ancient Greeks considered the most majestic in the sea and graphically represented them that way on temple walls. Yet it is a fish about which comparatively little is known. It is a fish that, before the sushi boom, swam in relative obscurity. But now, under the glare of the lights of television shows like Wicked Tuna and other publicity, some scientists think blue fin tuna's popularity is making it further removed from the shallow depths of scientific understanding.

Research funding at the LPRC has been deeply cut. Bush administration selective cutting of earmarks meant funding cuts to large pelagic research, both at the LRPC and the rest of the United States. “The programs are going away at the worst possible moment,” said Lutcavage. Congress has failed to pick up funding for these critical research programs.

Bluefin tuna has been a commercial and recreational fishery species for decades in the U.S. and Canada, yet very little good science has been done. Ironically, just as pressure on the stock has reached higher levels, the possibility of keeping it a viable fishery into the future has been jeopardized by these research funding cuts. There may not be a higher dollar value fish than the bluefin tuna, but that is not enough to turn Congress around on finding research funds to sustain it.

Funding cuts have driven the Large Pelagics Research Center to the edge of existence. Severing the continuity of the science threatens the value of decades of research. American Bluefin Tuna Association Executive Director Rich Ruais described the work done at the LPRC as “very high-quality cutting edge marine science.”

Ruais said the economic importance of bluefin tuna to the tuna fishing industry, which includes the fishermen, buyers and marketers, also extends to the party boat owners, lobstermen who take out tuna fishermen and the shoreside businesses that benefit from all of these.

*Comparative Assessment of the Reproductive Status of Female Atlantic Bluefin Tuna from the Gulf of Mexico and the Mediterranean Sea.

Read the entire abstract, introduction and paper: East vs west bft reproductive characteristics on spawning grounds- first ever comparison!
http://www.plosone.org/article/info%3Adoi/10.1371/journal.pone.0098233