CYCLES AND SCARCITY

I was perusing an Internet forum the other day, and came across a discussion of the Mid-Atlantic Fishery Management Council’s pending amendment to reallocate bluefish from anglers to the commercial sector.

A few of the folks who commented noted that bluefish hadn’t been to abundant off their local shores in the past couple of years, and asked whether it makes sense to increase bluefish landings (the reallocation is being considered because anglers don’t currently kill their entire quota, while the commercial folks are likely to harvest those fish if more quota was given to them) at a time when abundance seems to be down.

Predictably, someone chimed in, assuring everyone that bluefish appear “in cycles” and a temporary shortage was nothing to get too concerned about.

You hear that sort of thing quite a bit. 

A fish stock declines in abundance, perhaps new regulations are proposed, and folks start coming out of the woodwork talking about “cycles,” or the fish just going “somewhere else,” and arguing that no regulations are needed, because the fish will come back without any help from fishery managers.  It’s particularly common with bluefish, which exhibited a big decline in abundance early in the 20^th Century, but recovered to high levels of abundance in the 1950s and ‘60s, although no one has explained quite why.

Now, there’s no question that fish, like most animals, go through periods of abundance and scarcity that result from various changes in their environment.  But to call that a “cycle” is a stretch.

Merriam-Webster, the folks who are in the business of publishing dictionaries, define a “cycle” as

“an interval of time during which a sequence of a recurring succession of events or phenomena is completed,”

or as

“a course or sequence of events or operations that recur regularly and usually lead back to the starting point.”

In either case, the definition requires a “sequence or recurring succession of events,” that is, a multi-step process that predictably leads to a particular outcome.

Thus, the fact that fish populations may, at times, be lower than they are at other times does not mean that the decline is part of any sort of “cycle.”  That would require an identifiable sequence of events that would allow the decline—and the approximate timing of the decline—to be predictable ahead of time.  A host of one-time occurrences, including overfishing, could be behind fish growing more scarce, and two different declines aren’t necessarily caused by the same things.

But fishermen usually don’t think that hard when they invoke “the cycle;” they’re merely trying to avoid additional regulation.  As in “it’s not our fault, it’s the cycle.  The fish will come back on their own.”

But even if it is a natural event that causes fish populations to go down, that doesn’t mean that fishermen won’t play a role in making things worse.

Fish have adopted over millennia to survive natural fluctuations in abundance.

Striped bass, for example, seem to experience poor spawning success when warm winters are followed by a dry spring.  For a number of years in the late 1970s and early 1980s, the fish experienced consecutive years of poor spawning conditions.  Perhaps the population could have weathered the unfavorable weather, but when it was coupled by some of the highest harvest levels ever recorded, overfishing pushed the stock over the edge of collapse, and it took until 1995 to rebuild it.

When poor spawning conditions again occurred for much of the past dozen years or so, the striped bass population again entered a steep decline.  But this time, regulations already in place, although not as restrictive as many anglers would have liked, were just restrictive enough to keep the stock from going into a tailspin.  More restrictive management measures were put in place soon enough to maintain it just above the threshold that defines an overfished population.

In the Mid-Atlantic, the same thing happened with summer flounder.  Consecutive years of poor spawning success, for reasons that are still unknown, has caused the stock to steadily decline, and regulations that were perfectly adequate to protect a healthier stock began to result in overfishing.  Some people weren’t happy to see additional restrictions being placed on the fishery, but the rules were needed to keep the stock from becoming overfished, a situation that would have led to even greater restrictions.

Saying “It’s just the cycle” and taking no action would not have worked out there, at all.

Saying “the fish just went somewhere else, and they’ll come back” doesn’t do very well, either.  

That’s probably heard most often with respect to striped bass every time someone suggests reducing the harvest.  In that case, it usually takes the form of someone arguing that all of the bass are chasing bait offshore, coupled with a story about someone seeing stripers chasing mackerel or herring well out in federal waters more than three miles from shore, where fishing for them isn’t permitted.

It’s true that striped bass will sometimes chase bait ‘way out there, but their ventures away from the shore are usually short.  Research performed in Massachusetts, which involved placing acoustic tags in striped bass caught in federal waters and then monitoring whether they moved through detectors located inshore, found that

“a majority of the adult Striped Bass encountered annually on Stellwagen Bank [in federal waters] exhibit movement into Massachusetts state waters as part of their normal migratory and feeding behaviors.”

Even so, it’s common to hear fishermen say “they’re all out in deep water” when someone complains that the population seems to be on the decline.

Locally, near my home on Long Island, I see the same thing playing out with black sea bass.

For those of you who aren’t familiar with the species, black sea bass are a small—mostly under five pounds—but very good-tasting species, which are very popular with both private boat and for-hire anglers.  They are at high levels of abundance, exceeding their target spawning stock biomass by a significant amount, but have also been under a lot more fishing pressure ever since summer flounder abundance began to decline.  As a result, regulations have been substantially tightened to avoid overfishing.

A lot of people, particularly those in the party boat industry, focus only on the high biomass, and not on the high level of removals.  They constantly complain that the rules are too strict and that they should be able to kill many more fish.  At a recent meeting of New York’s Marine Resources Advisory Council, a party boat captain complained that the season should start at some point in May (it begins on June 23 this year) because all of the larger black sea bass in the Fire Island Inlet area “move east” after that, leaving only the undersized fish behind.

It’s a nice story, but it isn’t true.  

I’ve caught plenty of good-sized sea bass—four pound class fish—in July off Fire Island—when the season began in July.  When the season starts in June, you don’t catch many bigger fish a month later, and when the season began in May, large black sea bass tend to get scarce by the end of June.

But that’s not because they “move east”—unless they’re headed that way in the trunk of someone’s car. 

Black sea bass are structure dependent, and there isn’t that much structure off the South Shore of Long Island.  There are a few artificial reefs, which thestate is substantially expanding this year, there’s a little hard bottom and quite a few shipwrecks, if you know where to find them.  But that’s it.  

When the fish move onto structure, they’re very densely concentrated, and black sea bass aren’t exactly reluctant biters.

Put a party boat with thirty or forty or fifty anglers—or more—on board above a piece of structure, and do that two or three times a day with five or six or seven different boats for a couple of weeks, and most of the bigger fish on the piece are going to get cleaned off pretty quickly.  A few more will move in from elsewhere over time, but on the whole, the best time to catch a big black sea bass—other than while fishing offshore in the winter—is during the first couple days of the season, when the fish haven’t yet succumbed to the pressure put on them by private and for-hire boats alike. 

But “move east?”  No, they don’t do that. 

Don’t take my word for it.  More than ten years ago, two biologists from the National Marine Fisheries Service’s Northeast Fisheries Science Center spearheaded an extensive black sea bass tagging study.  The study found that there were northern, central and southern sub-stocks of the northern black sea bass stock, and that the inshore dividing line between the northern and southern sub-stocks was roughly Moriches Inlet, at the eastern end of Fire Island.

More significantly, from the standpoint of whether the big sea bass “move east” in early summer, the study found that

“During summer months fish throughout the stock remain stationary in coastal areas with very little mixing among adjacent areas.”

Given the findings of that study—that the sea bass “remain stationary” and that there is “very little mixing”—the notion that big fish “move east” is pretty well debunked, as there is no contradictory study that might seem to support that claim.  However, if you’re trying to convince regulators that regulations need to be relaxed, admitting that you’re already removing all the big fish off the wrecks under the current rules isn’t likely to yield the desired result, so I suppose folks feel that they have to at least try…

And that’s how it usually works with such stories, whether of “cycles” or fish “going somewhere else” for a while (not to be confused with fish really going somewhere else because waters are warming).

They’re all nice stories, but if you want healthy fisheries, stories aren’t good enough. 

You need sound science.  And science-based rules.