One of the great successes of nature management is the restoration of the Atlantic Coast striped bass population. After the commercial catch of stripers hit a record 14.7 million pounds in 1973, the population collapsed and a mere 1.7 million pounds was landed in 1983. A federal moratorium on recreational and commercial striped bass fishing in 1984 quickly turned the population around. By 1990, limited recreational bass fishing resumed, and in 1995, fisheries regulators declared the population restored. Now there is a proposal to reopen commercial fishing of stripers. It's considered a model relationship between man and fish, and in recent years anglers have caught stripers in numbers and sizes reminiscent of the old days.

There's just one problem: For the past 5 years, they've also occasionally caught stripers that are visibly diseased. Some have sores and ulcers on the outside. Most look fine until they're cut open, revealing ugly granular growths in their internal organs. Fishermen often don't notice infected fish because they don't cut them open. Usually they just remove large fillets from both sides of the back and then discard the rest. The disease is mycobacteriosis, once popularly called "fish tuberculosis." It was first discovered at the Philadelphia Aquarium in 1926 and has been seen sporadically in small numbers of fish since.

This time, it is different. It is caused now by a bacterium -- Mycobacterium shottsii -- which was only discovered in 2001 by the Virginia Institute of Marine Science while researching an outbreak of the disease in stripers that started in 1997. And it has already been found in more than half the fish sampled in the Chesapeake Bay, the main spawning ground for the Atlantic Coast population of striped bass. Early suspicions are that oxygen-depleting pollution and a decade of warmer-than-usual waters have stressed the fish and favored the mycobacteria. If so, then man's recovery plan for the striper may be incomplete.

The new mycobacteria, fortunately, doesn't thrive at temperatures warmer than 86 degrees, so it can only live on people's extremities as a persistent rash sometimes called "fish handler's disease." Scientists recommend gloves, hand washing, and quick release or disposal of infected fish to prevent it.

There is no danger of getting the disease from eating a striper. One reason is that cooking the fish to 170 degrees for 20 minutes kills the mycobacteria. Even if they got inside you, mycobacteria would find your body temperature too high to survive. Scientists think most of the infected fish will eventually die of the disease, but can't tell when. Too little is known about mycobacteriosis and its effect on reproduction to forecast whether this will bring about another crash in the striper population. If so, the great run of migrating stripers enjoyed by fishermen the past couple of years may only be temporary, even without the resumption of commercial fishing. And this time, I'm afraid, turning around the population might not be as easy.

The bacteria that causes aquarium fish mycobacteriosis is Mycobacterium marinum, a bacteria that grows best at temperatures below body temperature. Individuals cleaning fish tanks with any type of injury on the hands are subject to a risk of infection, usually of the skin and soft tissues. Other mycobacteria cause more serious disease in people, the most significant of which is tuberculosis caused by _Mycobacterium tuberculosis_. Mycobacterium shottsii may be capable of causing human disease similar to that caused by Mycobacterium marinum, and it would not be surprising if skin and soft tissue infection occasionally resulted after handling infected fish.