MANAGEMENT BOARD TO MONITOR STRIPED BASS RECOVERY

 

A recent update to the striped bass stock assessment, which found that the female spawning stock biomass of striped bass is likely to rebuild to its target level by 2029, and do so without any change to existing regulations, came as a surprise to just about everyone who has been following the striped bass management process.

There’s no question that it’s good news, although there is a fairly large portion of the striped bass fishing community which thinks that the news is a little too good—and maybe too good to believe.

While such suspicion is understandable given the recent state of the striped bass stock, a careful reading of the assessment update makes it clear that its conclusions are valid, provided that the assumptions on which such conclusions are based remain sound.

The soundness of such assumptions is always ripe for debate.

Although fisheries scientists frequently try to predict how a stock might fare in the future, they are not clairvoyant, but instead firmly rooted in the here and now.  The best that they can do is analyze the current size and composition of the spawning stock biomass, recruitment, fishing and natural mortality, etc. and, based on current values, predict what the stock will look like two, or five, or ten years from now, with the predictions growing ever more uncertain as they reach farther out in time.

If the future values of any of those parameters shifts from what they are today (or, more accurately, what they were during the terminal year of the stock assessment), then the stock’s future status will also vary from the scientists’ predictions.

The stock assessment update’s conclusion that striped bass spawning stock biomass will be fully rebuilt by 2029 hinges on the assumption that fishing mortality during the rebuilding period will remain the same as it was in 2021, when F=0.14.  That is a fishing mortality rate slightly below the target of F=0.17.

Because of an emerging retrospective pattern in the stock assessment update, which slightly underestimates fishing mortality, we can already suspect that the true fishing mortality rate in 2021 was just a little bit higher, somewhere around F=0.15.  That will somewhat reduce the probability of timely rebuilding, but the effect will not be too great; even if the fishing mortality rate rises to the 0.17 target, the stock is more likely than not to fully recover by the 2029 deadline.

But if fishing mortality rises above target, the stock is unlikely to fully rebuild by then.

Thus, after the stock assessment update was formally presented to the Atlantic States Marine Fisheries Commission’s Atlantic Striped Bass Management Board last Monday, some of the Management Board members expressed concern.

Massachusetts fishery manager Michael Armstrong noted that the assessment update’s projection was very sensitive to small changes in the fishing mortality rate; the 2021 rate of 0.14 provided a 78.6% chance of rebuilding the stock by 2029, but if that rate increased by just a few hundredths of a point, to the F=0.17 target, there was only a 52.5% chance of timely recovery.  And if the rate increased just three hundredths more, to the 0.20 threshold that defines overfishing, the probability of rebuilding by 2029 falls to just 30.5%, making failure more than twice as likely than success.

Thus, Dr. Armstrong advised his colleagues that

“I want the Board to be conscious…It doesn’t take a lot to change the course of this recovery.”

Emerson Hasbrouck, the Governor’s Appointee from New York, reinforced Dr. Armstrong’s comments, saying

“We’re getting close to being on the razor’s edge here.”

He asked when the next stock assessment or assessment update would be produced, and upon learning that nothing would happen until 2024, asked whether there might be an interim update next year.  ASMFC staff replied that, if the Management Board wanted such interim update, they could make a formal request to the ASMFC’s Interstate Fishery Management Program Policy Board, but also noted that the assessment schedule was already very full, and that conducting an interim bass assessment would mean that work on some other species would have to be delayed.

However, what the Atlantic Striped Bass Technical Committee can do, without unduly disrupting other already-scheduled assessments, is to wait until early next year, when all of the 2022 data is made available, and then compare actual 2022 landings estimates with the predicted landings from the assessment update.  If actual landings materially exceed predictions, there will be a need to revisit management measures in order to avoid keep fishing mortality low enough to rebuild the stock.

Such comparison would provide a good backstop to the assessment update for, as Dr. Armstrong reminded the Board,

“There are no output controls for the recreational fishery.”

That is, unlike the commercial fishery, where landings are constrained by hard-poundage quotas, the ASMFC sets no comparable annual catch limit for striped bass anglers, only a “soft” target fishing mortality rate that will hopefully be achieved through existing regulations.  If fish are particularly “catchable” in a given year, perhaps because big schools of bait are holding them near active ports, or if angling effort increases because of good weather of the comparative lack of other species, recreational fishing mortality can spike well above its target level.  Should that happen, anglers face no paybacks or other consequences for their excessive landings, and managers have no recourse that might prevent such excesses from recurring.

Dr. Armstrong noted that excessive recreational landings have doomed previous efforts to rebuild the striped bass population

“because we’ve never hit our target [fishing mortality rate], at least for any period of time.”

He further commented that

“Stocks don’t collapse overnight, but with four years of poor recruitment, we’re reaching that point.”

While it’s impossible to say just how far in the future “that point” might be, anyone who fished through the striped bass stock collapse of the late 1970s and early 1980s will recall that the first sign of impending problems was a sharp drop in recruitment; the school fish began to disappear, but because big striped bass still remained abundant, neither fishery managers nor most striped bass anglers took such warning sign seriously.

Still, there are those on the Board who saw no need for immediate action.  Stephen Train, a commercial fisherman who serves as Maine’s Governor’s Appointee, asked

“How much damage can we do if we let this go for another year?”

Similar thoughts were voiced by Tom Fote, the Governor’s Appointee for New Jersey, who stated that

“I’ve been sitting around the table for a long time.  We always say that we have to trust the science…I got involved in this whole process in ’86 because of striped bass…I agree with the stock assessment.”

At first, that seemed like a remarkable statement to come from Fote, who can usually be counted on to deny the truth of the science without offering any countervailing data or statistical support, other than a vague claim that, at some point in the past, the science turned out to be wrong.  His comment made more sense when put in the proper context:  Supporting the science would leave regulations unchanged, at least until after the next assessment is released in 2024; reviewing 2022 landings next spring could result in managers putting more restrictive regulations put in place for the 2024 season.  Since Fote is always trying to maximize the number of fish—not only striped bass, but any fish managed by the ASMFC—killed by anglers, his support of the assessment update’s conclusions was entirely predictable.

Fortunately, most of the other people in the room had more sense, and agreed that reviewing 2022 landings early next year was a good idea.  A press release issued by the ASMFC the day after the meeting quoted Martin Gary of the Potomac River Fisheries Commission, who chairs the Management Board, as saying

“This 2022 assessment was the first check-in point for progress toward stock rebuilding by 2029.  It is extremely important that we continue to monitor fishery removals and conduct stock assessments to keep evaluating rebuilding progress and stay on track.”

Such support for continued monitoring represents an important change of direction for the Management Board, which in the past tended to adopt a set of management measures, and then take no action until the next benchmark assessment, which usually occurred five years or so later, informed them that action was needed.  After the Board adopted Addendum IV to Amendment 6 to the Atlantic Striped Bass Interstate Fishery Management Plan in 2014, it took no further management action until after the most recent benchmark stock assessment, adopted in 2019, determined that the stock was both overfished and experiencing overfishing, even though the Board knew, by October 2016, that Addendum IV’s measures had not only failed to reduce recreational landings in the Chesapeake Bay, but were instead allowing such landings to rapidly increase.

While the conclusions of the stock assessment update were good news, such news was tempered by the realization that unanticipated changes in the level of fishing mortality, or perhaps other factors, could send the predicted recovery awry.

The Board’s expressed determination to continue to monitor the striped bass’ recovery, and keep it on track, should provide the striped bass’ advocates real reason for hope, and was perhaps the best news of all.