CONNECTIONS

There’s an article about red grouper that has been getting a lot of play on the Internet recently.

As anglers, we probably think of groupers as a complex of structure-dependent species that don’t need much more than a reef, wreck or rockpile to be happy, but in the case of the red grouper, at least, that stereotype does not hold true.

According to the aforementioned article, red groupers actually create their own structure by removing sediment to create hard-bottomed “holes’ that may be as much as 25 feet in diameter and several feet deep.  In doing so, they help to create a more diverse and species-rich habitat, as sessile organisms such as sponges and corals attach themselves to the newly-created hard bottom, and in turn attract the sort of crustaceans and smaller fish that live on higher-profile structure.

Those small fish include the young of commercially valuable species, particularly juvenile vermillion snapper (“beeliners”).

Nor does the grouper take a mere passive role, clearing off the bottom and allowing animals to settle at random.  The fish is aggressively territorial, and more than willing to chase off any other groupers, snappers and similar predators that move onto its patch.  In doing so, it provides an incidental service to the various small fish and other animals that share the grouper’s domain, greatly reducing their exposure to predation.

The impacts of such behavior has yet to be adequately recognized in the fishery management process.  Currently, the linchpin of red grouper management—and the management of virtually all other recreationally and commercially important fish species—is the concept of maximum sustainable yield, which can probably best be defined as the greatest number of fish that may be removed from a population on a continuing basis without causing such population to decline in abundance.

Such an approach can do fine if all we care about is red grouper, or any other individual species.  However, as the red grouper demonstrates, species do not live in a vacuum.  Their actions and abundance can and do impact other species as well.

In the case of red grouper, it is entirely possible—although I haven’t come across data that suggests it is true—that a decline in the population, which would naturally cause a decline in the number of red grouper “holes,” would deprive juvenile vermillion snapper of some portion of both their nursery habitat and protection from predators, and thus adversely impact vermillion snapper abundance.

It’s not clear that there is such a cause-and-effect relationship, but at the same time, it’s not at all clear that there’s not.  What is clear is that when maximum sustainable yield is the sole criterion used by fisheries managers, they ignore important relationships that, in the long run, impact the total productivity of our coastal ecosystems.

For a good example, consider the oyster toadfish (Opsanus tau) of New York’s bays.

For years, toadfish were one of those things that no one, whether angler or commercial fishermen, wanted to catch.  

They were slimy, ugly things, resembling nothing more than an oversized tadpole with spines and teeth, and if those teeth got a good hold on your finger, it hurt.  The Bay Daily reprinted a passage from the book Life in the Chesapeake Bay, and though it is describing Chesapeake toadfish, it applies to Long Island toadfish as well.

“Toadfish may lay claim to being the ugliest fish in the Chesapeake Bay, a vision for nightmares, slimy and ragged, with fleshy flaps hanging from their lips and over their eyes, covered with warts and with threatening, wide-gaping jaws armed with sharp teeth…When caught, it erects sharp spines on its dorsal fin and gills and snaps viciously with its powerful jaws.”

Nobody ever thought of eating the things or, if they did, never admitted to it in public.

But then things changed, as they usually do, and the New York region began to host newcomers from Asian shores, who had much broader minds than than we locals did when it came to edible seafood.

Suddenly, live toadfish became a hot item in local markets, and Long Island’s baymen found themselves in the midst of something that looked like a small-scale gold rush.

Toadfish were everywhere.  The baymen didn’t have to do too much different to catch them; the fish were already finding their way into blue crab and blowfish traps.  And best of all, there were no regulations.

The markets would take all of the big, mature toadfish that the baymen could catch, and pay very good prices, too. 

No one complained, or tried to limit the size of the baymen’s landings.  Even Long Island’s anglers, who were often the first to complain about the baymen's perceived excesses, stayed totally silent; toadfish were only a nuisance to them.

Then…something happened.  

After a very few years, the number of toadfish in the bays declined sharply.  On the other hand, the number of crabs in the bays—not the blue crabs, that go so well with melted butter and beer, but the smaller sort of crabs that folks don’t usually notice and definitely don’t eat—began to increase.  A lot. 

Toadfish like to eat crabs, the same little crabs enjoy nothing more than eating young quahogs—hard clams—when they are still very small and their shells not tough enough to endure a crab claw’s embrace.

A lot of the baymen were also clammers, and began to connect the dots.

They soon demanded that limits be put on the toadfish harvest, not so much to protect the toadfish themselves—although it had become hard to find the really big ones, which once were everywhere—but to protect the small clams.

And therein lies the lesson.

Single-species management cannot assure that America’s fisheries will thrive.  Coastal ecosystems are a web of species, connected by a web of relationships.  Some of those relationships are known to fisheries managers, although few are quantified and it is very likely that many remain only guessed-at or are completely unknown.

As we move into the future, it is crucial that federal and state fisheries laws give at least as much weight to the value of live fish in the water, where each species must fulfill its role in the greater ecosystem, as they give to the value of dead fish on the dock.

For as the toadfish and the red grouper teach us, all life in the sea shares connections.  If fisheries management is to be effective in the long term, managers must acknowledge those connections, and manage for the maximum productivity of not a single species, or a suite of species, but for the maximum sustainable productivity of the ecosystem as a whole.

And they must conserve not only the recreationally and commercially valuable species, but all species.  For like clams in Long Island’s bays, some of our most valued species may, in the end, depend on our most despised.

Thus, it is not our place to judge what species are worthy of conservation, and which are mere “trash.”  For evolution has already judged them, and found them all to be needed and good.

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NOTE:  Because Christmas Eve falls on next Thursday, when the next edition of One Angler's Voyage would normally be published, and because most readers will probably have better things to do on Christmas Day than read about fisheries issues, no additional essays will be published this week.  Instead, a new edition of One Angler's Voyage will not be released until Sunday, December 27.