IS IT TIME TO GIVE THRESHER SHARKS A HAND?

 

Back in 1971, the late, legendary Captain Frank Mundus, who pioneered recreational shark fishing off Long Island, New York, co-wrote Sportfishing for Sharks, a book that was, and though out of print still remains, the definitive book on that activity.  In the chapter dedicated to thresher shark fishing, Capt. Mundus wrote,

“You could go the full route of your shark-hunting career without ever contacting a thresher.  On the other hand, you might find yourself in an area at a time when they’re fairly numerous.  Their distribution is rather erratic and changeable.  It has been our experience threshers are seldom what could be called abundant.

“Even in one region their distribution can be a study in contrasts.  Off Montauk, New York, for example, we’ve seen threshers breach several times as the pursued small menhaden, and we know of five or six taken in these waters by trollers using wire lines for striped bass.  Yet during the course of a decade we’ve seen no more than a dozen or so hung on the docks at Montauk.”

When I moved out to Long Island a dozen years later, little had changed.

Shark fishermen usually said that they were “going out for makos,” which were abundant back then.  They landed a lot of makos between 200 and 400 pounds, with a lot more under 200 and a very, very few that went close to 1,000.  The fishing held up pretty well throughout the summer.  

Another, far smaller group of anglers specialized in the big tiger sharks—fish of 500 pounds or more—that were surprisingly common around deep structure once the water temperature rose into the 70s.

It was a completely unregulated fishery.  There were no minimum sizes, no bag limits, and no permits needed.  The concept of “prohibited species” had not yet been born, and there were a plethora of shark species available to fishermen.  While anglers said that they were “going out for makos” or targeting tigers, they had a good chance of catching a bunch of blue sharks, large numbers of sandbars, dusky sharks that might weigh anywhere between 20 and 500-plus pounds, the occasional hammerhead, the even more occasional white shark and, every now and again, a thresher.

Offshore fishing tournaments, which either targeted sharks exclusively or included a shark category among others for tuna and billfish, were ubiqutous.  From my dock in Babylon, New York, which lies just inside Fire Island Inlet, I could have fished a tournament every weekend from mid-June through the beginning of August, had I chosen to do so, without having to go very far from home.

While multiple shark species might be brought to the scales, when a tournament boat weighed a thresher, it always drew the biggest crowd, for it was often the first time that most of the folks on the dock had ever seen one.

Fifty years later, things are very different.

The shortfin mako population has crashed, due primarily to too many being caught and killed by the pelagic swordfish longline fleet.  In 2022, the United States, along with all of the other signatories to the International Convention for the Conservation of Atlantic Tunas (which applies not only to tuna, but to “tuna-like species,” which in the inscrutable language of diplomats includes things like swordfish, marlin and, of course, sharks) imposed a complete landings ban on shortfin makos In 2022, theUnited States, along with all of the other signatories to the InternationalConvention for the Conservation of Atlantic Tunas (which applies not only totuna, but to “tuna-like species,” which in the inscrutable language ofdiplomats includes things like swordfish, marlin and, of course, sharks)imposed a complete landings ban on shortfin makos which, because they were valued both for their fight and as food, were the most popular shark caught by recreational fishermen.  With the closure in place, scientists believe that the mako population has a better than even chance to rebuild in about 45 years.

Longliners also crashed the dusky shark population, which is in even worse shape than the makos, and probably won’t reach sustainable levels for at least another century.  They, too, may not be legally landed.  The same is true of sandbar and white sharks which, although showing strong signs of recovery, are still in the rebuilding stage.

Because of the prohibition on mako landings, many shark tournaments, as well as the fishing clubs that depended on them for much of their annual revenue, have shut down, while tackle shop owners and folks manning local gas docks tell me that, for the same reason, far fewer fishermen have been targeting sharks over the past few seasons.

Yet some tournaments, and some recreational shark fishermen, remain.

And their new favorite target, which is both legal to harvest and good to eat, is the common thresher.

That might not have been an issue if local ports still saw very few threshers each year.  But at the same time that other sharks were no longer available to anglers, catches of threshers began to spike.  Where, in the past, I might go a decade or more without having a thresher swim into my chum slick, in recent years, I’ve hooked as many as three in a single day.

That might sound like a good thing, and a sign of increasing abundance, but that’s not necessarily so.  The increase in encounters could be a sign of a growing population, but it could just as easily mean that the fish haven’t grown more abundant, but are merely more catchable, and there’s reason to believe that the latter is true.

With their small mouth and a whiplike tail that can be nearly as long as their body, thresher sharks have evolved to feed on densely schooling fish.  And in the past half-decade or so, the inshore waters off southern New England and the upper mid-Atlantic have seen a sharp increase in both menhaden and chub mackerel, exactly the sort of fish that threshers evolved to feed on. 

As a result, anglers have found thresher sharks right on their doorsteps.  Plenty of fishermen livelining menhaden just outside Long Island inlets, trying to tempt a striped bass, have gotten the shock of their lives after a 200 pound thresher, rather than a 20 pound striper, made off with their bait.  

Savvy shark fishermen have taken advantage of the situation, drifting along in the same menhaden schools as the anglers seeking striped bass, but with tackle designed to battle a big thresher.  I know of such anglers catching threshers weighing more than 400 pounds, while fishing in less than 40 feet of water.

And most of the thresher sharks caught by recreational fishermen are killed.  The Final Atlantic Stark Fishery Reveiw, released last year, notes that

“Common thresher sharks are unique among sharks in the recreational fishery in that they may be the only commonly caught species that is more likely to be harvested than released, with harvested thresher sharks accounting for 60 percent of the total catch.  Harvest estimates from 2014 to 2016 were approximately double or more relative to estimated releases.  The number of thresher sharks released increased significantly between 2017 and 2019 while the number harvested increased slightly after 2016…The bulk of the length distribution ranges from 55-96 inches [fork length] with a median size of 74 inches [fork length]”

The Final Review also notes that

“Prior to the implementation of new management measures in 2018 [that initially substantially restricted, and in 2022 completely prohibited, landing shortfin makos], shortfin mako sharks made up the majority of harvested pelagic sharks.  After that, there was a distinct shift to the common thresher shark, however annual harvest of common thresher shark increased only slightly…The pelagic shark fishery is largely driven by tournament fishing during the early summer months.”

If the thresher stock remains healthy, such catches pose no threat, but they could clearly be a big problem if the stock is in decline.  And the biggest problem of all is that no one knows whether the stock is healthy, because it has never been assessed.

I was recently appointed to the National Marine Fisheries Service’s Highly Migratory Species Advisory Panel, and attended my first meeting a few weeks ago.  Highly Migratory Species, unlike most other United States fisheries are not managed by regional fishery management councils, but instead are managed directly by the Secretary of Commerce, which effectively means that they are managed by HMS specialists at NMFS.  The Advisory Panel, as its name suggests, provides input intended to influence management actions.

So at the May Advisory Panel meeting, I brought up the issue of thresher sharks, suggesting the need for both a stock assessment and, very probably, more restrictive regulations in the face of their growing importance in the recreational fishery.  In particular, I noted that the current 54-inch (fork length) minimum size probably isn’t appropriate for a species that doesn't see 50% of females mature until they are at least  216 centimeters—about 85 inches, or a little over 7 feet—in length.

That’s nearly a foot larger than the average thresher landed by recreational fishermen today.

My suggestion that NMFS consider additional restrictions on thresher harvest, including a substantial increase in the size limit, received favorable comments from others in the room, and no one seemed to oppose it.

After all, in the end it makes sense.

I love shortfin makos for their beauty, their speed, and their magnificent jumps.  But I have always been a big thresher shark fan, admiring both their strength and their refusal to quit.  I’ve had threshers that died on the line rather than give up the fight.

Such fish deserve our respect.

We have already lost much of the mako fishery, although catch-and-release angling is still going on.  Right now, the thresher fishery still seems to be doing OK.  Which makes now the right time to lend it a hand, before it goes the same way as the mako.