Thursday, March 30, 2023



Last November, a stock assessment update revealed that, if fishing mortality did not exceed 2021 levels, there was a 78.6% chance that the striped bass stock would fully rebuild by 2029.  

2029 is an important rebuilding deadline, because the last benchmark stock assessment found the striped bass stock to be overfished, and Amendment 7 to the Interstate Fishery Management Plan for Atlantic Striped Bass, like Amendment 6 before it, requires that

“If female [spawning stock biomass] falls below the threshold, the striped bass management program must be adjusted to rebuild the biomass to a level that is at or above the target within an established timeframe [not to exceed 10 years].  [emphasis added]”

The benchmark assessment was accepted for management use in 2019, which started the rebuilding clock.

Unfortunately, last year’s big spike in recreational landings has completely changed the rebuilding outlook.  The Atlantic States Marine Fisheries Commission’s Atlantic Striped Bass Technical Committee met this morning, to review new projections that consider both the big increase in recreational fishing mortality and the possible increase in commercial harvest that would occur if the Atlantic Striped Bass Management Board adopts any version of Addendum I to Amendment 7 to the Atlantic Striped Bass Interstate Fishery Management Plan.

The news was not good, although it could have been worse.

In 2022, removals of striped bass from the population increased by 33.5% when compared with 2021.  That equates to a fishing mortality rate of 0.1873, just about splitting the difference between the fishing mortality target of 0.1679 and the fishing mortality threshold of 0.2013.  Thus, while the fishing mortality rate is clearly above the target, the stock is not experiencing overfishing.

The bad news is that, as one might expect from such a fishing mortality rate, it is highly unlikely that the stock will fully rebuild.  Note that I didn’t say that it was “highly unlikely that the stock will fully rebuild by 2029,” but rather “highly unlikely that the stock will fully rebuild.” 


Or, at least, not until the fishing mortality rate is reduced to a more appropriate level.

If the fishing mortality rate does not change, the stock is likely to rise above the spawning stock biomass threshold this year, meaning that the stock will no longer be overfished.  However, it is not expected to reach the spawning stock biomass target.  Instead, the recovery will most likely stall somewhere between the two values, with the stock showing a very slight decline by 2029 due to low recruitment in recent years.

As usual, the Technical Committee looked at a number of alternative scenarios when projecting the future of the stock; such alternatives included two different assumptions of the future fishing mortality rate and multiple assumptions of what the Management Board might do with respect to Addendum I.

The rosiest projection—which is far from rosy, from a stock rebuilding standpoint—gives the bass a 14.6% probability of rebuilding by 2029.  It assumes that the fishing mortality rate will remain constant, at an average of the level experienced during the years 2019, 2021, and 2022 (F=0.1837), and that the Management Board will not approve any of the Addendum I options.  Given such assumptions, there is also a 93.9% probability that the stock will not be overfished in 2029.

The least optimistic projection gives the stock only a 3.4% chance of rebuilding by 2029.  It assumes that the recreational fishing mortality rate will remain at its 2022 level, that the Management Board will approve Addendum I, and that all available commercial quota will be caught.  Such projection would also lower the likelihood that the stock would not be overfished in 2029 to 75.8%.

An array of options lies between those two extremes.

In the end, the Technical Committee decided to reduce the number of options it would present to the Management Board to just three; all would be based on a three-year average fishing mortality rate, which would be 0.1837 if Addendum I was disapproved, 0.1992 if the full commercial quota was caught, and 0.1987 if the full commercial quota was caught, with the exception of New Jersey’s, which is reallocated to the recreational sector.

It's hard not to notice that the latter two projections come uncomfortably close to the fishing mortality threshold of 0.2013, and hard not to remember that any projection includes a certain degree of uncertainty.

It’s not particularly clear why the Technical Committee decided to use a fishing mortality average from 2019, 2021, and 2022; in some ways, the decision seems difficult to defend. 

In 2019, recreational fishermen were still fishing under management measures developed in Addendum IV to Amendment 6 to the Atlantic Striped Bass Interstate Fishery Management Plan, which with few exceptions meant a 1-fish bag and 28-inch minimum size on the coast, and a 2-fish bag and 18-inch minimum size in the Chesapeake Bay.  Such management measures did not prevent the stock from experiencing overfishing, and were replaced by the current 28- to 35-inch slot limit, and complementary measures in the Chesapeake Bay, when Addendum VI to Amendment 6 to the Atlantic Striped Bass Interstate Fishery Management Plan went into effect at the beginning of 2020.

Thus, the 2019 fishing mortality rate would seem irrelevant to the current striped bass fishery.

In 2021, fishermen were governed by the current management measures.  Yet at this morning’s meeting, Dr. Katie Drew, a respected, long-time member of the Technical Committee, noted that managers recognized that 2020 and 2021 landings were unusually low, probably due to some combination of COVID and new regulations, and that the increase in 2022 most likely reflected a return to the norm, strongly abetted by the wide availability of bass from the 2015 year class, which fell within the bounds of the slot limit.

Given such considerations, basing projections on the 2022 fishing mortality rate would arguably have been a better choice; however, there isn’t that much difference between the two, and the reality is that the Technical Committee made the call to use the three-year average when it provided updated information to the Management Board.

The big remaining question is what the Management Board is going to do with the information, once they receive it.  Right now, nothing compels them to take any action.

Some of that flows from a sort of loophole in the ASMFC’s management process.  The projections described above are just that—projections—and do not constitute a formal stock assessment or stock assessment update.  Therefore, they do not necessarily spur any sort of management action.

Even if they were derived from an assessment, they wouldn’t have tripped any of Amendment 7’s management triggers, as the fishing mortality rate hasn’t risen above the fishing mortality threshold, and even though the current fishing mortality rate is above the target level, Amendment 7 requires that it remain above target for two consecutive years (while spawning stock biomass remains below target) before any management action is required.

On the other hand, Amendment 7 does require that the stock be rebuilt by 2029, and the latest projections make it clear that such rebuilding is very unlikely to happen unless fishing mortality is reduced. 

So the Management Board is going to have a decision to make.

It can begin a management action at its upcoming May meeting, which will reduce fishing mortality and make it more likely that rebuilding will occur.  Given that the fishing mortality rate isn’t all that far above its target level, it’s likely that a relatively minor action—perhaps slicing a few inches off the top of the slot limit, and so putting much of the 2015 year class off limits to anglers—could get things back on track.

Or, the Management Board can sit on its hands and do nothing, until after the 2024 stock assessment update is completed.  At that point, given this morning’s revelations, it will probably take substantial restrictions, perhaps including closed seasons, to accomplish rebuilding in the two or three years that will remain to get the job done.

The former option seems to make the most sense.  It would provide a couple more years for the bass to rebuild, and shield bass fishermen from potentially draconian rebuilding measures.  We can only hope that the Management Board sees things the same way.





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