Sunday, February 26, 2023



Preliminary Marine Recreational Information Program data for all of the 2022 season has recently been released.  It contains some bad news for striped bass.  Last year’s recreational harvest was about double the harvest in 2021.

Anglers landed an estimated 3,521,065 striped bass in 2022,  91% more than the 1,841,901 bass landed in the previous season.  Live releases were just about the same for the two years, with an estimated 29,458,293 bass released last season, versus 28,687,920 returned to the water in 2021.  If the accepted 9% release mortality rate is applied to those figures, we end up with a total of 6,172,311 striped bass killed by the recreational fishery in 2022, as compared to 4,423,813 in 2021.  

When harvest is measured in pounds, rather than in individual fish, the increase in 2022 landings is even more striking.  Last year, anglers landed 35,271,130 pounds of bass, an amount 123% above the 15,781,509 pounds landed in 2021.  Release mortality is not calculated in pounds, but only in fish, and so is not included in the foregoing figures.  (For those who might be wondering, no one believes that fishery managers can actually count every last bass caught, released, or harvested by recreational fishermen.  The figures provided are merely point estimates embedded in a range of values, defined by the “percent standard error” or “PSE.”  Actual catch, etc. is expected to fall somewhere within that range.  The PSEs for all estimates provided herein fall somewhere between 7.8 and 9.3, which indicates a relatively high level of precision.)

By comparison, commercial landings for 2021 were 577,363 fish, weighing approximately 4,290,000 pounds.  Commercial landings for 2022 have not yet been released, but given that the entire commercial quota, including both the Chesapeake Bay and ocean fisheries, is 5,412,802 pounds, there is a hard cap on how high such landings might go.  There is no cap on the recreational fishery.

With such a startling increase in recreational landings, the next question must be whether such increase will impact the recovery of the overfished striped bass stock.

The answer, as unsatisfactory as it might be, is that it is still too early to know.

Last fall, the Atlantic States Marine Fisheries Commission released an update to the striped bass stock assessment, which found that, in 2021, the fishing mortality rate was 0.14, somewhat below the fishing mortality target rate of 0.17.  The same update predicted that, if the fishing mortality rate remained at 0.14, there was a 78.6% probability that the spawning stock biomass would be fully rebuilt by the 2029 rebuilding deadline.  If the fishing mortality rate increased to the 0.17 target, the probability of rebuilding fell to 52.0%; if the rate increased even more, to equal or exceed the fishing mortality threshold rate of 0.20, it is unlikely that the stock would attain the spawning stock biomass target.

We’re now looking at a situation in which landings have roughly doubled—a little less than doubled, if measured in fish, and significantly more than doubled, if measured in pounds—but it’s important to realize that such increase does not equate to a doubling of the fishing mortality rate.  Despite the sharp increase in landings, it is possible—although probably not likely—that the fishing mortality rate has hardly increased at all.

That’s because fishing mortality is calculated as an annual rate of removals, and not merely as the absolute number of fish taken out of the population.  To calculate such rate, one must know not only how many fish were removed from the population, but how big the population was in the first place.

Even those two values don’t provide all of the information that’s needed, because different segments of the striped bass population experience different levels of fishing mortality.  Striped bass less than 18 inches long are universally safe from legal harvest, so the only fishing mortality that they experience comes from illegal landings and release mortality.  On the other hand, bass between 28 and 35 inches long may be harvested just about everywhere, although there are a few exceptions and, in some places, closed seasons apply.

To capture such differences, biologists employ the concept of “fully-recruited fishing mortality” which, if put in its simplest terms, is roughly equivalent to the fishing mortality experienced by that segment of the population that people are actually fishing for (my apologies to any biologists who might be reading this, for such a casual definition).  Fully-recruited fishing mortality can be calculated in more than one way, depending upon whether the person doing the analysis chooses to assume constant mortality across all the relevant age classes, or elects to break things down to the year-class level, but that’s more detail than we need to consider here.

The concept of fully-recruited fishing mortality, which is used when calculating striped bass removal rates, explains why the 2021 and 2022 landings are not directly comparable—the population of fish deemed to be “fully recruited” changes from year to year.

The 2015 year class of striped bass represents the strongest year class produced in the past decade.  While some of the 2015s grew faster than others, and entered the coastal slot limit prior to 2022, the majority of the 2015 year class could not be legally harvested in most places until last season.  Thus, while landings increased in 2022, the influx of 2015s into the fishery caused the population of bass used to calculate the fishing mortality rate to increase as well.  

At the same time, fish from the 2011 year class, which was also large, were growing out of the top end of the slot, and so were no longer a part of the generally fishable population.

Thus, until the Atlantic Striped Bass Technical Committee takes all of the factors into consideration and calculates the 2022 fishing mortality rate, we won’t know for certain how last year's landings will impact rebuilding.

At the same time, we can make a few informed guesses.

It seems pretty likely that fishing mortality was higher in 2022 than it was in 2021; it’s probably safe to predict that both the 0.14 fishing mortality rate, and the 78.6% chance of rebuilding the stock by 2029, now belong to the past.

Beyond that, preditions get harder to make.  While I think that the fishing mortality rate increased in 2022, it’s hard to guess where it might have ended up.  My gut tells me that there’s a good chance—probably a better than even chance—that fishing mortality exceeded the target.  I wouldn’t be surprised if the striped bass was again experiencing overfishing, but at the same time, I also wouldn’t be surprised if the fishing mortality rate remained below the threshold.

Without technical guidance, it’s impossible to know for sure.

The other thing that we can’t yet know is how the ASMFC’s Atlantic Striped Bass Management Board is going to respond to the increased recreational landings.

The increase certainly won’t catch the Management Board by surprise.  At its November 2022 meeting, Dr. Michael Armstrong, Massachusetts’ fishery manager, raised the issue on multiple occasions, noting at one point that

“I looked at the MRIP landings, and they are up considerably this year.  There is only one way we can react as a Board to low recruitment, and that’s maintaining an increasing [spawning stock biomass].  If in fact the retrospective is right and we’re a little bit higher and some of the other uncertainty and landings are up.  We may in fact be at the threshold already, after this year…

“But the main reason we are in this situation is we have never hit our target [fishing mortality rate], at least for a prolonged period of time.  To prevent that we need to know what [the fishing mortality rate] is.  I would advocate for something, either an update, or what Katie [Drew, of the Atlantic Striped Bass Technical Committee] was talking about, to kind of give us an idea within one year of where we’re at.  That’s because mostly of the recruitment.  We need to get [spawning stock biomass] up, which may not work, but that’s all we can do.”

After some discussion, the Management Board and ASMFC staff came to a general agreement that the Technical Committee would compare the projected 2022 catch level needed to maintain the 0.14 fishing mortality rate with the actual 2022 landings.  If the actual landings were significantly above the projections, the Board might either take some sort of management action, or wait until the next stock assessment update was released late in 2024.

Dr. Armstrong wasn’t altogether pleased with the latter alternative, saying

“I don’t know quite how to react to that, other than you know we’re not locked in…if we find that landings are high, and projected to go above [the fishing mortality rate], we could always cut harvest without a quantitative assessment.  I could sit here and make a motion and say, let’s cut harvest by 10 percent.

“I don’t know what it will do.  It may cause people to go crazy.  But I just think we’re in a spot that we need to react.  That being said, stocks don’t collapse overnight.  But with 4 years of poor recruitment, we’re approaching that point, in my mind…”

So the stage is set for the Management Board to act when it meets in May.

At that point, the Technical Committee will be able to provide it with a comparison of 2022 landings to the landings projections contained in the last stock assessment update.  If the landings are well above the projection, I strongly suspect that someone, very possibly Dr. Armstrong, will move to place additional harvest restrictions in place.  I also suspect that some Management Board members will be very opposed to such motion.

At that point, the Management Board will have a choice.  It could decide to take preemptive action, in the absence of a formal stock assessment update, to keep the striped bass stock on a path to timely rebuilding.  Or it could decide to sit on its hands and do nothing, and instead wait for the next stock assessment update to be released late in 2024 which, unless managers vote to fast-track the process, would probably result in no management changes becoming effective before the 2026 season.

If excessive fishing mortality continued through 2025, the 2029 rebuilding deadline would probably be completely out of reach.

If low recruitment accompanies such high fishing mortality, the striped bass might stand on--or even beyond--the the brink of the stock collapse that Dr. Armstrong hopes to avoid.

The Management Board's May meeting could well turn out to be one of those critical times, when the health of the striped bass stock hinges on a single vote.

We can only hope that any such vote goes the right way.




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