By CHRISTOPHER TUFFLEY
christopher.tuffley@newssun.com
SEBRING -- For a fish, tilapia is shrouded in mystery.
It's not that the fish is new or rare. Tilapia is sometimes called St. Peter's fish because of a reference to it in the Bible, and some populations thrive to the point of crowding out native species.
The mystery is how a species native to the Levant and western Africa spread so readily throughout South Florida's rivers, streams and lakes.
No one knows for sure.
According to the Florida Museum of Natural History, the first finding of a tilapia in the American wild occurred at the Snapper Creek Canal in Miami-Dade County in 1974.
A good source of protein, with a mild but pleasant taste, tilapia had already become a fish of interest for commercial fishermen and aquaculturists. Because they are herbivores, tilapia are not a sport fish. Typically they are caught using nets. But hook-and-line fishermen have found bread balls make good bait.
Starting in about 1972, they were imported into Florida as an experiment in fish farming. Today tilapia is the third most important fish in aquaculture, surpassed only by carps and salmonids.
Somewhere along the line, however, whether intentionally or by accident, they ended up in the wild.
Another puzzle is how they spread into land-locked lakes, like Lake Jackson and Dinner Lake, which have significant populations. A large number of the fish washed up on the shores of Little Lake Jackson last week, apparently victims of the cold weather.
The fish is both a benefit and a pest.
In Kenya, for example, they are used to control mosquitoes because they eat the insect's larvae, thus helping combat malaria.
And because most species of tilapia eat algae and plants like duckweed and water meal, some cities have intentionally introduced tilapia into their canal systems or public ponds.
Arizona, for example, uses the fish to keep the canals providing city drinking water free of vegetation to reduce the cost of purification.
But introduced into the wild, tilapia have proved to be a problem.
Not because they compete for food, said Gary Morse of the Florida Fish and Wild Life Conservation Commission, but because they compete for space and bedding areas. Tilapia grow quickly, and as long as the water temperature remains above 60 degrees, they thrive. It doesn't take long for them to crowd out native species, like largemouth bass.
The fish can cause havoc in a short time.
The World Conservation Union, a global group of nations that includes public agencies and private organizations, tracks the status of different animal and plant species. It has placed tilapia on the list of 100 of the world's worst invasive species.
Bass do eat tilapia larvae, Morse said, but the tilapia are engaged parents, pairing off during spawning season and keeping the larvae in their mouths for safekeeping. They prefer creating their nesting areas near structures -- not just rock overhangs, but weedy areas too.
Highlands County Lakes Manager Clell Ford said that, especially in the spring, a person can wade along a lake's edge and find deep holes that look like bowls. The tilapia dig them when spawning.
"Most of the holes are ankle or calf deep," he said, "but step into one and you can be in waist deep water or deeper."
Sunday, January 31, 2010 - www.newssun.com/0131-ct-tilapia-history