COVERING TAMPA BAY AND ITS WATERSHED |
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The number of suckermouth armored catfishes and brown hoplos in west central Florida appears to have increased, particularly in the Hillsborough River, according to a recent study by Florida Marine Research Institute ichthyologists Dr. Ramon Ruiz-Carus and Dr. Harry J. Grier. Ruiz-Carus and Grier compiled records from five estuaries to examine the distribution of the South American invaders. Incidental collections, museum specimens and fisheries independent monitoring indicate an increase in exotic catfish, as well as other non-native fish, from 1990 to 2003. Researchers are examining samples of armored catfish from the Hillsborough River to document larval development and morphological differences helpful in identifying fish belonging to the family Loricariidae, which includes more than 550 species. They also are estimating growth rate and age of sexual maturation to compare with data on native populations.
While suckermouth catfish have been present in local waters dating back to the 1950s, the brown hoplo is a more recent omnivorous invader more likely to compete with native fishes. Both fish likely came to Tampa Bay from private aquariums. "People toss their fish into the rivers all the time," says USF marine biologist Dr. Ernst Peebles. Two years ago, Peebles caught a juvenile brown hoplo in the Alafia River. They appear to be moving north from Charlotte Harbor where they're present in large numbers, he says. The brown hoplo is a delicacy in Venezuela and Trinidad. The fish are roasted whole over a fire, then cracked open. It is becoming the target of a small fishery in the upper St. Johns River. So what does the study suggest? Step one is understanding what you are dealing with. The study sought to accurately identify the non-indigenous species out there, so bay managers could evaluate appropriate strategies. But the rub, says Peebles, is that you typically don't know the damage until it's done, because nobody has the model to predict the impact. Not all exotics are bad. From citrus trees to rose bushes, examples abound of non-native plants that have been introduced and filled an important niche. Other invaders, like the Asian green mussel, can wreak havoc. First discovered in Tampa Bay in 1999, the aggressive bright green mussel was probably a hitchhiker in ballast water. It gloms on to bridge pilings, docks and other hard surfaces, crowding out native species, and has already spread as far south as Charlotte Harbor. For more information, contact Ruiz-Carus at ramon.ruiz-carus@fwc.state.fl.us.
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