|Florida Fish: Non-Native Florida Fish (4)|
Tilapia (Tilapia mariae) The spotted tilapia is native
to West Africa from the coastal lowlands and brackish lagoons of central
Ivory Coast to southwest Ghana and from southeast Benin to the Kribi
River, Cameroon. Non-native populations are established in Arizona,
Florida and Nevada. First collected in 1974, spotted tilapia rapidly
became the most abundant fish in the canal system of Miami-Dade County
where it makes up about 25% of the fishes by number and weight. Spotted
tilapia is now widespread south of Lake Okeechobee, and is so abundant
that the butterfly peacock fish was introduced to help control it.
Spotted tilapia inhabit calm, warm waters and in their native range are
most common in small streams or the lower reaches of medium-sized
rivers. Among cichlids and perciform fishes, spotted tilapia are
conventional in size and shape. Their bodies are essentially oval. The
spinous and soft dorsal fins are confluent and originate well behind the
head. The spinous dorsal is longer than the soft and the rigid spines,
more numerous than the soft rays, are sharp. The caudal fin is fan
shaped and truncate. The anal fin tapers to a point rearward and is
armed with three stout spines in the front. The pelvic and pectoral fins
are of a size proportional to the body and their placement is typical
for an acanthopterygian fish. The mouth is terminal and the eye is
large. Spotted tilapia are prey to a variety of organisms including
other fishes, birds, reptiles, and humans. Omnivorous, feeding on wide
variety of food items, spotted tilapia feed low on the food chain. The
spotted tilapia grows to 13 inches and about 3 pounds; males grow larger
with all fish over 10 inches typically being males.
Suckermouth Catfishes (Pterygoplichthy multiradiatus) All three suckermouth catfishes (family Loricariidae) in Florida have rows of bony plates covering all but their belly area. Sailfin catfish are distinguished by worm-like pattern of dark markings on the head over a dark-golden background; pectoral fins stout with rough surfaces resembling course sandpaper; disc-like, protrusible mouth is under the head, and used like a suction cup to attach and feed on algae; females tend to be smaller, and fish larger than 18 inches probably males; lifeless and hollowed-out 'armored' bodies sometimes seen on canal and lake banks. Although the suckermouth catfish has been in Florida since the 1950s, it is not widespread, being found primarily in Miami-Dade and Hillsborough counties. The vermiculated catfish is occasionally found in central Florida, including Six-Mile Creek in Hillsborough County and the St. John's River. Native range for all loricariids is South America. Poor success of suckermouth catfish to date indicates it is less well adapted to Florida waters than are the sailfins. 100% of stomachs that were examined contained detritus, and most also contained algae, sand, small freshwater bivalves, water fleas, and decaying matter, suckermouth catfishes are most active around dusk when they root around the bottom looking for worms and insect larvae. They use their sucker-like mouth, with their spoon shaped teeth, to scrape algae from stones and other surfaces. Suckermouth catfish grow to more than 20 inches and weights of 3.0 pounds.
Swamp Eel (Monopterus albus) Swamp eels are fish, but they are not closely related to other living eels or snake-like marine and freshwater fishes. Unlike the native American eel (Anguilla rostrata), swamp eels do not migrate to the ocean to spawn. The swamp eel family includes more than a dozen species. They are native to Central and South America, Africa, Australia, and from India to eastern Asia, including much of China. In Asia, swamp eels are widespread and commonly sold live in markets as food for human consumption. The eels were first found in Florida in 1997, with three populations are known. Sites include canals in the northern Miami area, a small drainage near southern Tampa Bay, and a canal system close to Homestead near Everglades National Park. The swamp eel has an elongate or snake-like body with no noticeable scales or fins. The head is relatively short and the teeth are small and not easily seen. The gill opening forms a V shape on the lower throat area. The body and head are dark, sometimes dark olive or brown above, but lighter, often light orange below. Some individuals are brightly colored with yellow, black, and gold spots over a light tan or almost-white background. The skin produces a thick mucous layer making the eels difficult to hold. Asian swamp eels are predators that eat a variety of animals including crayfish, shrimp, worms, frogs, tadpoles, and other fishes. Swamp eels can grow as long as three feet and weigh about a pound.
Walking Catfish (Clarias batrachus) Walking catfish possess a large accessory breathing organ which enables them to breath atmospheric oxygen. They are well known for their ability to "walk" on land for long distances, especially during or after rainfall. Walking catfish, which are scaleless, are typically a uniform shade of gray or gray-brown with many small white spots along their sides. The head is flat and wide and the body tapers to the tail. The eyes are very small and the mouth is broad with fleshy lips and numerous small pointed teeth in large bands on both the upper and lower jaw. There are four pairs of barbels, one pair each of maxillary and nasal barbels and two pairs of mandibal barbels. The fish has a lengthy dorsal and anal fin that each terminate in a lobe near the caudal fin. The pectoral fins, one on each side, have rigid spine-like elements. To move outside of water, the fish uses these "spines" and flexes its body back and forth to "walk". The walking catfish is easy to distinguish from many of the other North American catfish because it doesn't have an adipose fin. The walking catfish are a widely distributed species found across Southern Asia including Pakistan, Eastern India, Sri Lanka, Bangladesh, Myanmar, Thailand, Malaysia, Indonesia, Singapore, Borneo, Laos and the Philippines. They are found across southern Florida. In the early 1960's, the walking catfish was imported to Florida from Thailand for the aquarium trade. The first introductions apparently happened in the mid 60's when adult fish, imported to be brood stock, escaped from Penagra Aquarium in Broward County and/or from a truck transporting brood fish between Dade and Broward counties. In 1967, the state of Florida banned the importation and possession of walking catfish. However, this led to another release of the fish into the wild. Fish farmers in Tampa Bay who possessed the fish purposefully released them so that they would not be found in violation of the new law.
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