Oh, sea nettle, where is thy sting?


August 06, 1994|By TOM HORTON

Jennifer Purcell, a researcher with the University of Maryland, is "disturbed" by this summer's extreme scarcity of one of Chesapeake Bay's most abundant species.

Only she's not talking about the downturn in crabs like everyone else. It's the medusan flotillas of Chrysaora quinquecirrha, the stinging sea nettle, that she misses.

Cold weather this spring, combined with one of the largest influxes of fresh water in the bay's recorded history, have depressed nettle reproduction to where Dr. Purcell can scarcely find enough for her research.

And honestly, who but she, who has chosen a career studying

"the gelatinous zooplankton," would care?

Not bathers, for whom the nettle's sting is far short of fatal but often surpasses the "annoying" level ascribed in scientific literature.

Not watermen, who say that hauling crab pots clogged with nettles is what separates men from boys; and who compare a tentacle blown into the face to someone extinguishing a red-hot cigarette in your eyeball -- except the cigarette would quickly go out.

Not even fellow scientists in her lab at Horn Point near Cambridge, for whom nettles are nothing but nettlesome obstacles to their own probing of the bay's submerged grasses, oysters and fishlife.

That's how it is when you are a nettle researcher. People only want to know you when there are lots of them around; and then only to ask: Can't you get rid of them?

In fact, there's little we can do, Dr. Purcell says.

During the 1960s, when we were still infatuated with the false promise of DDT and other miracles of chemistry to eradicate pests, there was a good deal of enthusiasm for finding such a "final solution" for the bay's sea nettles.

In 1970, after several warm, dry springs, and a lot of pressure from Maryland's congressional delegation, President Richard M. Nixon signed the Jellyfish Control Act -- one more reason, in retrospect, why he may be better remembered for his foreign policy successes.

Chemicals enough to make a dent in the bay's nettle population also would have done in much of the estuary's marine life.

Attempts to introduce predators that would eat the nettles, like the sea slug, also failed.

A burst of false hope came a few years ago when attempts were made to start a processing plant to turn the nettles into human food. Certain varieties of jellyfish (a grouping that includes the bay's stinging nettles) are eaten by the tens of millions of pounds, mostly in Asia.

Dr. Purcell has acquired recipes, if not a taste, for such selections as duck and jellyfish salad, and shredded jellyfish and chicken with mustard and peanut sauce; but alas, our home-grown nettles turned out "too soft-bodied" to process.

No matter. There is a lesson for us in all of the above; by no means a dispiriting one.

You can choose to grudge the nettle for its ineradicable nuisance; or you can choose to marvel at one of nature's most elegant adaptations.

Though chrysaora ranges from New England to the Gulf Coast, nowhere does it flourish as in the Chesapeake Bay. The sea nettle is ideally suited to salinities that range from a little fresher than the ocean, to a little saltier than the rivers -- precisely what you find in much of the estuary, where rivers and the ocean mix.

Virtually nothing else that eats the nettle or competes directly with it, from sea turtles to other jellyfish, is adapted to occur abundantly in the same range of salinities.

With a body structure that is virtually all water and salts (only two-thousandths organic material by weight), the nettle requires very little in nutrients, so the nutrient-rich bay can easily support innumerable quantities of them.

The Chesapeake, with its shallow, oystery bottom, provides abundant anchoring spots for the polyp stage of the nettle's life cycle. Encysted thus on the bay bottom, it survives the harshest winters and the coldest, wettest springs.

When conditions turn favorable, the polyps begin budding forth the familiar, tentacled medusa forms, which in turn drift through the summer bay producing larvae that sink to the bottom to form more polyps.

It is, in sum, such an exquisite fit within the bay ecosystem as to be inextricable and indomitable.

The nettle gives us neither food nor comfort; but it teaches us accommodation, tolerance, humility -- qualities at least as important as technology and science in our struggle to find our own fit with the rest of nature.

In the unlikely event that Maryland, whose state dog, boat, fish, fossil and university mascot already relate to the bay, were to entertain a state pest, I would lobby hard for the summer sea nettle.

(Yes, I hear the clamor of those who would say: Make mine mosquitoes. But everybody's got stinging insects; only the bay is world-class in its abundance of stinging nettles).

Meanwhile, Dr. Purcell's research has shown that the sea nettle may actually play a role beyond giving us food for thought. They may help out the oysters.

Baltimore Sun Articles
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.