Sunday, April 26, 2026

WESTERN ATLANTIC REGULATIONS MAY THE THE KEY TO HEALTHY BLUEFIN TUNA STOCKS

 

We’ve known for a long time that Atlantic bluefin tuna migrations are complex, with fish spawned into the Mediterranean Sea traveling into North American waters, while fish spawned off North America were thought to cross the ocean to swim off European shores.  Now, thanks to a recent paper published by a team of scientists led by Dr. Barbara A. Block of Stanford University’s Department of Biology and Department of Oceans, we also know that the bluefins’ sojourns to the western Atlantic may be particularly important to tuna stocks’ health.

“Ensuring the future of Atlantic bluefin tuna,” which appeared in the April 20, 2026 volume of the Proceedings of the National Academy of Sciences, reviews three decades of archival, satellite, and acoustic tagging data, and advises

“that exploitation of Med-spawning fish, particularly on the spawning grounds, may impact all fisheries in the North Atlantic basin through their extensive distributional range,”

and also that

“Shifting selectivity to older year classes releases juvenile bluefin from the Med to the higher productivity of the North Atlantic, where they experience multiple years of growth and lower fishing mortality before returning to their spawning grounds.”

The National Marine Fisheries Service issued a press release heralding the research, in which Eugenio Pineiro Soler, NOAA’s Assistant Administrator for Fisheries, was quoted as saying,

“Management of this internationally shared resource requires high quality scientific information—and this work provides one example of that.  This research addresses one of the primary sources of uncertainty surrounding the amount of mixing and movement occurring between these two stocks.  This is a critical piece of information needed to inform sustainable yield advice.”

The cross-ocean movements of Atlantic bluefin have long been an issue for not only scientists and fisheries managers, but anglers and commercial fishermen as well; there has always been the questions of whether restrictive regulations constraining harvest of the western stock might be frustrated when tuna cross into the eastern Atlantic, where more permissive management measures prevail, and whether the relatively small United States quota makes sense in the face of the far higher quotas awarded to nations that fish in the Mediterranean and eastern Atlantic.

The new paper answers those questions, noting that

“electronic tagging results for adolescent and mature fish indicate that the Med stock subsidizes the North American fisheries and, importantly, exploitation of Med spawning fish, particularly on the Med spawning grounds, impacts all [Atlantic bluefin tuna] fisheries in the North Atlantic.”

As NMFS explains,

“The results show that many bluefin tuna move from eastern Atlantic and Mediterranean waters to the western Atlantic to forage and grow.  These fish often remain in the west for several years before returning to the Mediterranean Sea or spawning in the Slope Sea.  Tagging also demonstrated that adult fish tagged in the U.S. and Canadian waters move back to the Mediterranean to spawn and often return the following year to the western Atlantic to forage along the U.S. eastern seaboard.  Importantly, bluefin tuna that originated in the western Atlantic, however, tend to stay west of the 45oW management line.”

The reason that eastern stock bluefin often migrate into western Atlantic waters appears to be food, with NMFS suggesting that

“Tuna are likely heading west to find and feed on vital prey such as Atlantic mackerel, Atlantic herring, and menhaden, which are abundant in U.S. and Canadian waters.”

But regardless of why many of the eastern stock bluefin move west, the movements of the eastern and western stocks make it clear that management measures intended to protect the western stock bluefin are not compromised by significant numbers of those fish traveling to eastern Atlantic water.  However, the many eastern stock bluefin that enter the western Atlantic also receive such measures’ protection, to the benefit of both North American fishermen and the bluefin themselves.

The paper notes that the eastern stock is thought to be about 10 times as large as the western stock, although there is substantial uncertainty surrounding that number, and that the total allowable catch for the eastern stock is 40,570 metric tons, compared to just 2,726 metric tons for the western stock.  Fishing activity in the eastern Atlantic was and is also much more intense, with the paper stating that

“From 1990 to the mid-2000s, estimated fishing mortality F was, adjusting for underreporting, typically 0.15 to 0.20 [or, very approximately, 15% of the population removed each year] for eastern juveniles (ages 2 to 5) and 0.3 to 0.4 [roughly 25 to 35 percent annual removals] for large individuals 9age 10+), concentrated primarily in the Med.  This period of heightened catch did not occur in the west…or north…, meaning that migrating to the West or North Atlantic provided eastern [Atlantic bluefin tuna] with relative safety from fishing mortality for almost 20 [years].  [citations omitted]”

It thus advised that

“In the Med, shifting selectivity of fishing to older ages in recent years and reducing [total allowable catch] not only controlled overfishing but created, in effect, an escapement management regime…that allowed migrating eastern [Atlantic bluefin tuna] juveniles and subadults to enjoy a longer, safer, and more productive juvenile growth period than those remaining in the Med.  Effectively, an unknown number of Med juveniles were able to ‘escape’ selection at an early age, forage, and reach maturity in the North Atlantic.  We hypothesize that this led to higher spawning contribution per recruit, higher overall abundance, and greater fishery yields, with the lower exploitation rates of North American fisheries providing a release from fishing mortality…  [citations omitted]”

But it wasn’t only the eastern stock that benefited.

“[F]or the western stock, as the supply of eastern [Atlantic bluefin tuna] increased the relatively static western area [total allowable catch] exerted decreasing mortality upon the western stock.  After years of relative stasis, the western-only larval and [longline fishery] catch indices in the Gulf [of Mexico] now show substantial increases indicating that growth of the western stock may have only responded due to managing fishing mortality of the eastern stock…  [citations omitted]”

The management measures adopted for the western stock three decades ago proved to be a conservation success story for the entire Atlantic bluefin tuna population.  As NMFS observed,

“The major conservation and management measures taken by ICCAT, combined with shifting catches to larger fish, resulted in a dramatic turnaround of the stock.  Reducing fishing mortality to sustainable levels allowed several year classes of fish to survive, grow, and leave the Mediterranean to seek the productive feeding grounds of the North Atlantic.  This escapement from Mediterranean spawning areas to wider Atlantic waters with stricter harvest measures allows bluefin tuna to live longer, grow larger, and contribute more offspring to the population.  This emphasizes the importance of managing fishing mortality in areas of high vulnerability such as spawning aggregations…

“Whether the current Atlantic bluefin fishery total allowable catch remains sustainable in the face of a rapidly changing ocean and increasing human demand remains uncertain.  What is certain is the return on investment for state-of-the-art science.

“U.S. anglers have been frustrated in recent years by strict harvest measures for bluefin, but the science confirms that these measures are effective.  Our conservation efforts are having huge impacts—not just for the United States, but across the Atlantic.  Anecdotal evidence supports this, with anglers along the U.S. East Coast catching more and larger bluefin than in the past 30 years.  The stock recovery is such that ICCAT adopted higher total allowable catch for the western stock…”

Yet, among all of those positive comments and unqualified support for good fisheries science lurks a substantial amount of irony. 

For more than a year, the current administration has repeatedly sought to cut the funding and the personnel needed to perform fisheries science at NMFS, whether that science be “state-of-the-art” or the sort of routine surveys and data collection needed to perform basic management tasks for a wide array of species.

And, specific to Atlantic bluefin tuna, it has made the groundless claim that the United States need not count recreationally-caught bluefin tuna against its annual quota, although there appears nothing in any ICCAT recommendation that would support that position.

Nor is it completely clear where the notion came from, although a recent article that appeared in The Fisherman magazine might make one suspect that it arose somewhere within the recreational fishing industry.  That article read, in part,

“There is no doubt that there is a booming recreational and for-hire fishery in the Mediterranean and Eastern Atlantic waters with little catch data being submitted for too many years now.  Earlier this year the [European Union] implemented new mandatory, daily electronic data reporting requirements for marine recreational fisheries targeting certain species, including bluefin.  However, other nations that are not part of the EU but are part of European and African continents are reporting little if any recreational catch, despite landings occurring.  There is still a glaring disconnect.”

The article fails to mention that the only two non-EU countries in the Eastern Atlantic are Norway, which has a national recreational quota of a whopping 10 metric tons—fewer bluefin than anglers killed off the southeastern United States during the first two weeks of 2026—and the United Kingdom, where the recreational quota is a still-tiny 20 mt.  There are more non-EU nations bordering on the Mediterranean Sea, but they include states such as Albania, Bosnia and Herzegovina, Serbia, and Montenegro, none of which are known as recreational fishing powerhouses, and none of which have any recreational quota at all.

So, the argument that the United States is justified in not counting its recreational landings against its quota because some non-EU nations might be doing the same thing falls pretty flat.

Yet the article goes on.

“The ICCAT Eastern Atlantic/Mediterranean management requires that recreational catch be reported and assigned to one’s quota.  The U.S. has argued that a parallel requirement does not exist for the Western Atlantic contracting parties in Western bluefin management Recommendation 22-10.  As a result—and because of the lack of recreational catch recreational catch reporting for many years now by the Eastern Atlantic/Mediterranean contracting parties—the U.S. notified ICCAT in January 2026 that it is exploring continuing to meet its requirement to report our recreational catch but not count it against the US quota…

“Not surprisingly, this proposal has been heavily criticized by our friends across the pond.  It should be noted that our recreational quota is negligible in comparison to the Western and Eastern Atlantic/Mediterranean bluefin quotas that are dominated by commercial quota allocations.”

Once again, we see arguments of dubious merit.

Recommendation 25-05—which superseded Recommendation 22-10 at last November’s ICCAT meeting—clearly states,

“An annual [total allowable catch], inclusive of dead discards, of 3,081.6 [metric tons] is established for 2026, 2027, and 2028…If the total catch in the western area exceeds 3,081.6 t in any year, it shall constitute an exceptional circumstance…  [emphasis added]”

To argue that “total catch” included dead discards, but excluded recreational landings, would be ludicrous.

In addition, Recommendation 25-05 is generally sector neutral; while it mentions recreational fisheries twice, it only mentions commercial fisheries once.  The natural counter to the argument that the Recommendation doesn’t explicitly require including recreational landings in the quota is that it doesn’t explicitly require including commercial landings, either.  The only explicit references are to “total catch” and “dead discards.”  Yet the mandatory counting of commercial landings against the quota is assumed.

But the ultimate argument for counting recreational landings against the U.S. quota is that it would be in the long-term interests of United States fishermen to do so.  As the new research indicates, the restrictive management measures in place in the western Atlantic benefited both the eastern and western bluefin stocks.  Placing greater fishing pressure on fish in the western Atlantic now, by omitting recreational landings from the United State’ quota and so increasing the western kill, could only risk reversing three decades of progress.

In the end, “Ensuring the future of Atlantic bluefin tuna” is a very valuable bit of research.  NMFS was completely justified in calling it “state-of-the-art science.”

But the thing about state-of-the-art science is that, while it is a good thing in and of itself, it is far more valuable if it is actually put to use.  NMFS shouldn’t just issue press releases hailing the paper.  It should put the paper’s findings to practical use, and continue to cooperate with the ICCAT management scheme that made the western Atlantic a valuable sanctuary for bluefin tuna for the past 30 or more years.

 

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