USGS · 5223714
No abstract available.
Explore connections, maps & timelines
W. Hoffman, T. H. Fritts, R.P. Reynolds. 1981-10-01. Whale sharks associated with fish schools off south Texas. https://doi.org/10.18785/negs.0501.08
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The blackchin tilapia, S arotherodon melanotheron , was first collected from the Indian River system, in Brevard County, Florida, in 1980. Since its introduction, this species has expanded its range northward along the coast approximately 37 km, to just north of Whites Point, Brevard County, and southward about 68 km to Vero Beach, Indian River County. Laboratory studies on salinity tolerance indicate an ability of this species to tolerate hypersaline concentrations of at least 100 ppt, and to reproduce in salinities of up to 35 ppt. The northern distribution of blackchin tilapia is almost certainly limited by cold temperature; however, the potential exists for extensive coastal, and possibly inland, invasion south of its present limits.
A review of historical and recent records of manatee ( Trichechus manatus ) sightings along the coast of the northern Gulf of Mexico indicates that their numbers have declined in Texas, but increased in Louisiana and Mississippi. This is due to their extirpation in Mexico and dramatic increase along the southern Big Bend coast of northwestern peninsular Florida. The distribution of manatees along the southern Big Bend coast is related to their need for warm water and the distribution of fresh water and submerged aquatic and marine food plants. The spring-fed headwaters of Crystal and Homosassa rivers are important warm water winter refuges; nearly 90% of the same individuals return each winter. The estuaries and grass beds associated with these two rivers and the Suwannee, Withlacoochee, and Chasshowitzka rivers are the principal summer habitats. The Suwannee and Crystal rivers are "high-use" rivers, whereas the other three are "low-use" rivers. Low human-caused mortality, high fecundity, some immigration, and high site fidelity are responsible for the increasing numbers of manatees using the southern Big Bend coast. Since this region of Florida has experienced relatively little development compared with the rest of the state, the best long-term future for this endangered marine mammal in the United States lies along the southern Big Bend coast.