CATCHABILITY

 

Fishermen and fishery managers often disagree about the health of fish populations.

A while ago, I reported on a recentstudy that tried to explain just why that is so, and why fishermen andfisheries scientists can look at the same fishery and come away with completelydifferent conclusions.  But in today’s edition of One Angler’s Voyage, I want to spend a little more time on one particular source of conflicting perceptions, the question of “catchability.”

Fishermen often, and understandably, tend to gauge the health of fish stocks by what they are catching.  If they’re not catching fish, the stock must be in trouble.  On the other hand, if they’re catching well, the stock must be healthy, and when biologists suggest otherwise, they’re labeled as office-based pencil pushers who “don’t spend time on the water;” if the comment comes from within the fishing community, it’s quickly dismissed as coming from someone who isn’t a “real fisherman,” who knows what’s actually going on.

Yet those making such superficial and simplistic comments rarely take the time to try to understand why other people’s perceptions vary so far from their own.

The answer is often “catchability,” which the International Seafood Sustainability Foundation desfines as

“The extent to which a stock is susceptible to fishing; quantitatively, the fraction of a fish stock that is caught by a defined unit of the fishing effort.”

In other words, sometimes fish can be relatively easy to catch, even though the stock is depleted, while at other times, even fish that are part of a healthy stock can be dismayingly hard to find.

The recent history of the striped bass fishery in the New York Bight provides a good look at the catchability issue.

There is no doubt that the striped bass stock is overfished.  The most recent benchmark stock assessment found that bass have been overfished since 2009, while the latest stock assessment update revealed that, while the spawning stock biomass is slowly increasing, it remains below the threshold level that defines an overfished stock.

Yet New Jersey’s spring striped bass catch data seems to tell an entirely different story.

For the years when the stripedbass spawning stock biomass was at its peak—let’s say, for the sake of this discussion, the five years between 2002 and 2006—the number of striped bass caught in all of New Jersey during March and April averaged a little under 550,000 fish.

For the next 14 years, as the spawning stock biomass declined and the stock became overfished, the number of striped bass caught off New Jersey in March and April actually increased, averaging about 665,000 fish for the years 2007 through 2020.

But then something remarkable happened.  In 2021, New Jersey’s recreational fishermen caught slightly over 4 million striped bass, most of those fish coming from the vicinity of Raritan Bay.  That number dropped to about 1.7 million bass in 2022 and 2023, but was still well above any year prior to 2021.  Not all of those fish were caught in or around Raritan Bay, but there is little doubt that the Bay’s sharp increase in striped bass abundance was responsible for most of the spike.

Raritan Bay began to develop a reputation as the new promised land for striped bass anglers.  In an April 2023 article in Salt Water Sportsman, the author declared,

“Montauk has long been known as ‘Mecca’ for striped bass fishing, but I think that’s about to change.  New York’s famed location is going to have to give up the title to its little brother, New Jersey.”

But he may have spoken too soon.  During March/April 2024, New Jersey anglers only caught a little over 1 million striped bass, less than they caught in 2005, 2007, or 2009, strong years that occurred during a 21-year period when catches were relatively low.

Something similar occurred in the fall.

During the period of peak striped bass abundance, 2002-2006, New Jersey’s striped bass catch during November and December averaged around 1.8 million fish.  For the 14 years between 2007 and 2020, that average declined, to around 1.65 million bass per year, with annual catch generally tracking the size of the spawning stock biomass.

But beginning in 2021, catch spiked to levels never recorded in this century, reaching nearly 3.2 million fish in 2021, about 4 million in 2022, and 6.1 million in the last two months of 2023.  Again, much of that catch occurred in the New York Bight, although the majority of it happened in the ocean, and not in Raritan Bay.

There was such a disconnect between what the stock assessments were saying and what the fishermen in the New York Bight were catching that some anglers, and many members of the for-hire fishing fleet, refused to admit that the striped bass stock was not in good health.

Some comments submitted to the Atlantic States Marine Fisheries Commission’s Atlantic Striped Bass Management Board, prior to its consideration of Addendum II to Amendment 7 to the Interstate Fishery Management Plan for Atlantic Striped Bass, reflected such anglers’ and captains' disbelief that fishing in New York Bight could be so good if the stock was not in good shape.  The commenters said things like

“in the New York Bight area we now have some of the best striper fishing I have ever seen in my life.  This is due to the fact that the Hudson River stock is in great shape.  However, we are denied access to them because of the declining Chesapeake Bay stock.  I believe that as the population of the Hudson River stock increases so does their range.  They are heading further North, South and East providing great sport in areas where they never used to travel to.”

And,

“I am absolutely sure that there are many more Stripers in the population today than at any time in my life time.  As a matter of fact even as I am writing this there is fantastic striper fishing going on from Long Island, New York to Virginia Beach.”

As well as,

“The fishing this Fall in New York and New Jersey is unbelievable.  I read where, on an average trip, every patron on a 65 foot head boats [sic] lands at least five fish a trip in the 40 to 50 pound range.  The fishing continued for weeks.  Where did these fish come from?  It is my believe [sic] that your data collection system has missed large schools of large fish.”

And finally,

“New Jersey has the most exciting, and one can argue the healthiest, Striped Bass fishery in many generations.  Conservation is an important measure to ensure a sustainable future for this amazing fishery for a generation to come—no one doubts that—but with such a great fishery unique to this area, it begs the question of whether we need to come to terms with a truth, backed by data—not all waters governed by ASMFC are created equal.

“The 2023 Emergency Action was a commendable action to preserve the Chesapeake Bay stock—which isn’t healthy—but data shows the Hudson River stock continues to outperform its average and there is an abundance of bass in all size ranges.  In addition to scientific evidence, anecdotal reports from party boat and charter boat captains will tell you that they haven’t seen the type of Striped Bass migrations in the Spring and Fall that we experience today…

“The 2023 Emergency Action’s application in New Jersey is not backed by science, data or any educated fisherperson’s POV in the area.  It’s an unnecessary protection that creates unnecessary barriers of entry to this sport…costing the for-hire fleet and those that it supports (bait shops and other businesses supported by fisherman [sic]) dearly.”

In each case, the commenter was willing to advance a position that has no scientific support (“the population of the Hudson River stock increases,” “there are many more Stripers in the population today than at any time in my  life time,” “your data collection system has missed large schools of large fish,” “the Hudson River stock continues to outperform its average.”) than to consider the possibility that there may be a reason that they are catching more bass in recent years, despite the depleted stock.

And there is a reason:  The recent abundance of menhaden in the New York Bight.

The author of the Salt Water Sportsman article alluded to that fact when he wrote,

“Jersey politicians did one thing right: Getting the Omega 3 bunker boats out of state waters.  That has allowed a vast biomass throughout the year in Jersey waters.  This draws behemoth bass into the bays, river systems and alongshore to fatten up on omnipresent adult bunker.”

For it was the presence of the bunker—Atlantic menhaden—in Raritan Bay and the New York Bight, in far greater numbers than in past years, that drove the striped bass fishery.  The big bass bunched up under the bunker schools, making them far easier to find and far easier to catch, than they were before 2021.  The striped bass did not suddenly become more abundant—given the size of the fish being caught, if it was really a matter of abundance; if it were, that abundance would have been seen in earlier years’ catch data, as even larger numbers of younger fish passed through the fishery.

The Hudson River did not suddenly begin turning out large numbers bass that could somehow, miraculously, grow from egg to 40 or 50 pounds over the course of a single year.

But the menhaden could concentrate the available striped bass in a relatively small area and make them easier for anglers to find and to hook—that is, the bunker made the bass for more catchable.

It's no coincidence that in the spring of 2024, when menhaden abundance in Raritan Bay was lower than it had been in the three preceding years, New Jersey anglers started catching fewer striped bass.  Those that found and fished over menhaden schools still managed to catch a lot of fish, but with schools harder to find, the overall number of striped bass caught plummeted.

And that's not a bad thing.

While increased catchability might prove a temporary boon for anglers, it doesn’t do much good for the fish, as it leads to an unexpectedly high number of bass being removed from the population, as either landings or release mortality, and because it makes anglers doubt the science behind fisheries management, and reduces their willingness to work with the management system.

The difference between catchability and abundance is very real.

So when a fisherman, whether recreational or commercial, starts catching a big load of fish, their first reaction ought not to be “There are plenty of fish in the ocean; the science has to be wrong,” but rather “With fish this easy to catch, we’d better not take home too many,” because further depleting an already depleted stock is never a good idea.