ICCAT TURNS ITS ATTENTION TO BLUE SHARKS

 

Everyone seems to take blue sharks for granted.

Anglers love the swift, high-flying mako, and fight dogged battles with thresher sharks.  Producers of televised nature shows, along with the folks who watch such productions, seem obsessed with white sharks, whether they’re feeding on seals off Cape Cod or cruising through azure Mexican waters.  Bull sharks have a reputation for gnawing swimmers off southern beaches, while blacktips off Florida’s Volusia County take a few nuisance nips out of surfers each year.  Greenland sharks make the news just by living slowly and sticking around, perhaps for three or four centuries, and earning acclaim as the longest-lived vertebrate in the world.

But blue sharks?  They are largely ignored.

And maybe that’s not too surprising.  The blue shark’s soft-textured, often ammonia-tainted meat isn’t valued as food, and rarely, if ever, shows up in markets.  While quite a few are caught by anglers each year, their fight is usually unremarkable, as blue sharks don’t jump, don’t run very fast, and—at least in the sizes typically caught by recreational fishermen—aren’t particularly strong.  They’re a cool-water fish which, when the ocean is warm, often don’t fight at all; they merely take the bait and allow an angler to bring them straight in to boatside, where they finally might thrash and roll after someone grabs the leader and tries for a stress-free release.

And still, I have a soft spot in my heart for the things.

When I started to fish for sharks back in the late 1970s, they were the first sharks that I caught.  And there have been plenty of days since then, mostly in early June, when blue sharks were the only fish that came between me and a good skunking; there have been other June days when the blue sharks were so thick that we’d have a dozen in sight at one time, and baits barely had a chance to sink beneath the surface before they were eaten.  On days like that, when you run out of hooks and bait well before you expected, the sheer quantity of the fish makes up for the quality of their fight, and lets you shake off the cobwebs of winter before the hoped-for mako or thresher arrives.

Most shark fisherman might not admit it, but we’d miss the blue sharks if they disappeared.

Thus, I was pleased to learn that the International Commission for the Conservation of Atlantic Tunas—which, despite its name, also manages sharks, swordfish, and marlin—has recently taken action that should help to maintain a healthy North Atlantic blue shark population.

It’s not that blue sharks are in trouble.  ICCAT scientists released a stock assessment earlier this year, which suggests that the population is right about where it ought to be for the population to produce maximum sustainable yield.  At the same time, the assessment notes that

“The Kobe plot indicates that there is a 49.6% probability that the stock falls currently falls within the yellow quadrant of the Kobe plot [meaning that the stock is overfished, but not experiencing overfishing], a 49.7% probability that the stock falls within the green, and less than a 1% chance that it is in the red or orange quadrants.”

If there is only about a 50-50 chance that the stock is healthy, and about an equal chance that it has become overfished, some sort of regulatory action is probably needed.  Even so, the blue shark is now in a better place than it was a couple decades ago.

Because of its low-quality meat, blue sharks do not support a directed fishery, but are instead caught as bycatch in fisheries targeting swordfish and tuna.  About 99% of all blue shark landings are attributable to the pelagic longline fisheries, primarily those prosecuted by the European Union nations of Portugal and Spain.  Their primary value comes from their fins, which are generally shipped to China and other Asian nations.

North Atlantic blue shark landings remained low through the mid-1980s, when North Atlantic blue shark biomass was about twice the level needed to produce maximum sustainable yield.  However, the fishing mortality rate increased sharply throughout the 1980s, at which point the stock began to experience overfishing, with F sometimes rising to 150% of the fishing mortality threshold.  Overfishing occurred on a regular basis through 2018, after which landings, and the fishing mortality rate, declined.  By the early 2000s, overfishing had driven blue shark abundance down to just 70% of the biomass needed to produce MSY yet, beginning sometime around 2005, biomass started to increase, and the stock regained its ability to produce maximum sustainable about ten years later.

ICCAT scientists, combining the results of two different stock assessment models, have now determined that maximum sustainable yield for North Atlantic blue sharks is 32,689 metric tons, and that landings above 35,000 metric tons, if continued for an extended period of time, would cause the stock to decline to a low level of abundance.

North Atlantic blue shark landings for the period 2019-2021 averaged just about 24,500 metric tons per year.  ICCAT scientists determined that such level of landings, or any level up to 27,500 metric tons, would have a greater than 50% chance to keep blue shark in the so-called “green quadrant” of the Kobe plot—that is, not overfished, and not experiencing overfishing.

Based on that information, the United Kingdon, at this year’s recently concluded ICCAT meeting, submitted a document which noted that the then-current total allowable catch for North Atlantic blue sharks, 39,102 metric tons, had only a 3% chance of preventing the stock from becoming overfished or experiencing overfishing (or both) by 2033, and proposed setting a new TAC of 27,500 metric tons.  Such proposed TAC was well above recent landings levels, and so would not require any nation to reduce its landings, while offering a 60% probability that the stock would be neither overfished nor experience overfishing during the next decade.

It appeared to be a reasonable proposal, but it was aggressively opposed by the European Union, which lands more blue sharks than the rest of the ICCAT nations combined.  As a result, the best that ICCAT could do was agree on a compromise measure, which lowered the total allowable catch to 32,689 metric tons, precisely equal to the maximum sustainable yield, with no provision to account for scientific or management uncertainty.

While it was an improvement over the old TAC and, if followed, has a fair chance to shield the North Atlantic blue shark from overfishing, and while it will have no real impact on either the fish or the fishery unless landings rise from current levels, it certainly wasn’t the ideal outcome.

Some nations, including Spain and Portugal, report very different levels of shark harvest to ICCAT than they report to the United Nations Food and Agriculture Organization, creating substantial management uncertainty as to which data are correct.  Many ICCAT member nations are also very lax about reporting shark discards to the Commission.  Under such circumstances, managing to the TAC, based only on reported landings, could allow overfishing to occur.

Since the primary value of blue sharks lies in their fins, it was also somewhat disconcerting that, for the 15^th consecutive year, a United States proposal that sharks be landed with their fins still naturally attached, which had the support of 25 other nations, was blocked, once again, by Japan.

Despite the proposal’s flaws, Ali Hood, Director of Conservation for the non-governmental organization Shark Trust, noted that ICCAT’s recent actions to manage blue sharks

“do represent steps in the right direction,”

although Hood also admitted that

“we are frustrated with the EU’s dogged prioritization of continued fishing dominance over the need to promote equity and minimize risk to shark populations that are already in a precarious state.”

It was the EU, one must recall, that was the primary roadblock to adopting no-harvest rules for the shortfin mako, at least after U.S. abandoned its objections in 2021, and the EU seems just as determined to scuttle more restrictive blue shark management measures.

On balance, the ICCAT actions, while imperfect, still helped promote a sustainable blue shark fishery.

And while anglers here in the northeast would rather catch threshers or makos, it’s still nice to know that, on those slow, early-season days when the water’s still cold and the makos (which themselves are in some trouble right now) are scarce, there will still be enough blue sharks around to keep us awake and alert until something a little faster and stronger finally decides to swim into our slicks.