Mating for life in the sea


Fidelity: Parasitic male angler fish, which live below 3,000 feet, avidly seek out female angler fish and hang around forever.

December 19, 2003|By Tom Horton | Tom Horton,SUN STAFF

TODAY'S a two-parter, including an intriguing new way to grade the health of the bay.

But first we ponder a touching question about the nature of male marital fidelity -- is it true love, or just blood-lust and sex?

The question arises from a recent ramble through the huge fish specimen collections at the Virginia Institute of Marine Science at Gloucester Point.

A female angler fish, floating in preservative, caught my attention. No beauty she, dark and lumpy, with degenerate little eyes and a size and shape resembling a distorted football more than anything streamlined and fishlike. She is mostly a huge mouth full of huge teeth -- portals to her huge stomach.

From her forehead sprouts a slender, rodlike organ, the "esca," terminating in a bioluminiscent tip that she flashes, as an angler would a lure, to attract prey in the eternally black, near-freezing depths below 3,000 feet, far off the mouth of the Chesapeake Bay.

You wonder who could love her, but male angler fish seek her avidly and mate for life, says Jack Musick, Acuff professor of marine science at VIMS, who has collected a world-class assortment of deep-sea fish.

"Mating for life," a quality that hopeful humans too easily have assigned other species, has taken a beating recently. Observation and DNA evidence has proven "cheating" among species ranging from penguins and songbirds to other primates.

But it's semper fidelis among male angler fish, though perhaps not in a way to warm the cockles of the human heart.

You must understand, Musick says, "that it's hard to make a living down deep" where angler fish dwell. Most marine food production occurs, and is consumed, closer to the sunlit surface. There just isn't enough food down below to support many of the big females. They are scattered far and wide in the lightless deep.

So the little males -- who never get bigger than a tadpole -- are equipped in their "courting" stage for one purpose only, to find and glom onto one of those scarce lady footballs.

They have big eyes, the better to spy her bioluminiscent "lure." They have outsize olfactory organs, the better to sniff out the sex attractant that females are thought to exude.

Once they meet, he is hers forever. Biting into her side with sharp, recurved teeth, he fuses to his lady love, taking his nourishment from her blood.

His big eyes and big smell organs regress, turning into testes. He becomes her lover, her constant companion -- her literal parasite.

"Cool fish," says Musick. Even he does not know what the female thinks of this arrangement, but some have been observed with multiple, blood-sucking males burrowed into their flesh.

@SUBHEDLooking for a better way to grade health of the bay

For six years, the Chesapeake Bay Foundation has produced a "State of the Bay" report card, grading the Chesapeake's health, from fish and habitat to water quality, on a scale of zero to 100. The high score is the bay when Capt. John Smith mapped it in 1607.

The bay now scores a disappointing 27. The foundation report card is well worthwhile as a rough gauge of improvement or regression in our bay cleanup efforts.

But it falls short of the detailed and comprehensive science-based assessment that could help guide and target specific restoration efforts around the bay.

In July, scientists from the University of Maryland's Horn Point Environmental Laboratory did a one-week pilot study aimed at a more sophisticated report card, the kind you might use as the basis of a cleanup effort -- or, if it came to that, take into court.

They sampled more than 150 sites, the length of two bay rivers, the Patuxent and Choptank. The two offer a nice contrast, with the former's pollution mostly from development and sewage, and the latter's largely from agriculture.

Both were compared to a "reference" site, at Cape Charles, Va., near the bay's mouth, where the influence of the ocean affords relatively clean water.

Scores were compiled for water clarity, important to underwater grasses, for oxygen vital to aquatic life, and for polluting nutrients like nitrogen and phosphorus.

The results? Both rivers scored an F for water quality in their upper reaches. The middle Patuxent got a C- while the middle Choptank got a D-. Both rivers got a D+ in their lower reaches. At the mouth, the Patuxent scored a C, the Choptank a D+.

Overall, it was D+ for the Patuxent, a D for the Choptank. The Cape Charles site scored a B+.

The effort is the start of a much more ambitious annual report envisioned by the university, one that would include the whole bay, and also scores for fish and habitat.

It needs to happen. It has great potential for communicating in a timely fashion, in irrefutable terms, where problems are and where progress is occurring.

Like the more simplistic bay foundation report, the pilot study confirms that problems still far outweigh progress.

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