On March 1, the National Marine Fisheries Service (NMFS) issued emergency measures intended to protect the shortfin mako shark from continued overfishing.  The measures became effective on March 2.

Prior to the new rule, no size or trip limits restricted the directed shark fishery, which included shortfin makos, although vessels that held an Incidental shark fishing permit were limited to 16 sharks per trip. Now, commercial fishermen must release all live mako sharks with a minimum of harm.  Pelagic longliners may retain any makos that are dead when the line is retrieved; all other commercial fishermen may not retain makos under any circumstances.

Recreational fishermen may still retain shortfin makos, although the minimum size limit was increased from 54 to 83 inches(measured from the tip of the snout to the fork of the tail).  Anglers are requested to release any shortfin makos that they catch, although vessels that hold either an Angling or Party/Charter Boat Highly Migratory Species permit (or an Atlantic Tunas General Category or Swordfish General Commercial permit, if participating in a recreational fishing tournament) may still retain one shortfin mako per day.

The emergency regulations were imposed after new scientific information revealed that the shortfin mako population in the North Atlantic was badly overfished, and declining in abundance.

Last summer, a satellite tagging study performed by scientists at Florida’s Nova Southeastern University and other institutions, suggested that shortfin makos were experiencing a far higher level of fishing mortality than biologists had previously believed.

Earlier studies had relied on fishermen to report the recapture of tagged shortfin makos; the relatively low numbers of tag “returns” was believed to indicate a relatively low level of fishing mortality.  The satellite tags, which let scientists know that makos had been recaptured without requiring any reports from the fishermen, told a very different story.  About 30% of the tagged fish were caught, suggesting a mortality rate ten times higher than previously believed.

The Nova Southeastern study presaged additional information that came to light later last year, after the International Commission for the Conservation of Atlantic Tunas (ICCAT) prepared a new stock assessment for the shortfin mako.

A previous ICCAT stock assessment, completed in 2012, found that shortfin makos in the North Atlantic were not overfished and, very probably, not subject to overfishing.  NMFS adopted those findings and relied upon them to manage the U.S. fishery.  However, ICCAT’s 2017 stock assessment came to a very different conclusion.

The 2017 assessment found that historical estimates of fishing mortality, which were largely derived from reports made by longline fishermen, were too low, and that the actual catch was significantly higher.  Based on the updated estimates, biologists performing the stock assessment determined that shortfin makos in the North Atlantic were both overfished and subject to overfishing.

They also found that if fishing continued at current levels, abundance would continue to decline.  Three separate population models used to assess the stock agreed that current fishing mortality, which includes not just harvest, but also fish that are discarded dead or die after release, would have to be reduced by about 75%, to just 1,000 metric tons (about 2.2 million pounds), to halt the decline.

Unfortunately, there is only a 25% chance that such a reduction would rebuild by 2040—twenty-two years from now.  And scientists aren’t sure that such a reduction can be achieved merely by releasing all makos that are caught. 

That shouldn’t surprise anyone familiar with the sharks.  It takes female makos at least six or seven years to mature, although some research suggests that it may take three times that long—about twenty years—before a female can first reproduce.  Once females do mature, they can produce anywhere from four to twenty-five pups at a time, with older, larger females producing more pups than do younger individuals.  A female shortfin mako will probably only reproduce once every three years.

Such a life history makes the shortfin mako population very vulnerable to overfishing. It also makes managers’ job harder, as both recreational and commercial fishermen often want to harvest, rather than release, any makos caught.

Because of that, a number of conservation organizations asked ICCAT to prohibit all shortfin mako landings.  However, because of the species’ economic value to both the commercial and recreational fisheries, a majority of ICCAT’s member nations, including the United States, opted for a proposal that will allow some to be harvested.  Because the United States is a member of ICCAT, it is bligated to adopt regulations that comply with such proposal.

There is no question that shortfin makos support an important recreational fishery off New England and the Mid-Atlantic, where years of overfishing have had a noticeable effect.

When Capt. Frank Mundus pioneered what he called “Monster Fishing”—recreational fishing for sharks—off Montauk, New York, in 1951, big makos frequently appeared close to shore, in chum slicks set out for bluefish.  Fishing for shortfin makos remained relatively good through the 1980s, when the season ran from around Memorial Day well into November, and fish weighing more than 200 pounds were regularly caught throughout the summer.  Today, most of the larger fish are caught during a short, four- or five-week window in June and July, with a few more landed when the water cools during the fall.  Even during the peak periods, shortfin makos have become noticeably less abundant, and the average size of the fish caught has declined.

Thus, anglers should view NMFS’ emergency measures as one step toward better management of the shortfin mako.  The measures will remain in effect for 180 days; after that, NMFS has the option of extending them for another 186 days.  After that, they will expire.  However, NMFS will almost certainly replace them with permanent regulations before that occurs.

Anyone who wishes to comment on the emergency regulations may do so on or before May 7 by either

  • Going to the Federal e-Rulemaking portal, searching for NOAA-NMFS-2018-0010, clicking on “Comment Now” and filling in the requested information, or
  • Submitting written comments to National Marine Fisheries Service, Highly Migratory Species Management Division, 1315 East-West Highway, Silver Spring, MD 20910; envelopes should be marked “Comments on Atlantic Shortfin Mako Emergency Rule”.

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