Macho Waters

Some river pollution spawns body-altering steroids

On the way back from a field trip to one of Alabama’s barrier islands in the late 1970s, W. Mike Howell and the students in his vertebrate biology class detoured over the state line into Florida to collect some fish.

Samples of water collected downstream of a pulp mill (left) and from a neighboring unpolluted creek (right). Jenkins

The mosquitofish at top is a normal, pregnant female from Spring Creek. In the middle are three Fenholloway River females in various stages of masculinization. Their anal fins are longer than normal and resemble the narrow gonopodium on the Spring Creek male (small fish heading toward bottom).