Biology, Population Estimates, and Movement of, Native and Introduced Striped Bass, Apalachicola River, Florida

Abstract

Striped bass (Morone saxatilis) in the Apalachicola River, Florida, were tagged from 1978 to 1982 to estimate population size, measure growth, monitor movement, and determine the exploitation rate. Native Gulf Coast striped bass (STB-G) and introduced striped bass from the Atlantic Ocean (STB-A) have occurred together in the Apalachicola River system since 1966 when STB-A were first stocked. Growth of both races was similar and comparable to growth in other waters. In 1981, the population estimate for all striped bass more than 381 mm long in the upper Apalachicola River was 1,500-2,000 fish, of which 43% were STB-G, 51% STB-A, and 6% intermediates. STB-G larger than 600 mm SL had statistically significant (P = 0.05) higher yearly average condition factors. Average percent weight loss during the summer was less (9.4 vs. 15%) in STB-G than in the STB-A race striped bass. The population of fish age 7 and older was composed of 29% STB-G and only 8% STB-A. Longevity of STB-G was greater (maximum age 12 vs. 8). Mean length of STB-G and STB-A above 250 mm FL was 587 and 552 mm, respectively. Yearly tag loss was estimated to be 17.7%; exploitation, 22%. Four hundred and twenty-two striped bass were tagged of which 53 were recaptured by anglers and 34 by survey crews. Eight showed a significant amount of movement, with six (3 STB-G, 3 STB-A) traveling upstream through the lock at Jim Woodruff Lock and Dam, and two (STB-A) traveling downriver into the Gulf of Mexico and eastward to the Ochlockonee River, Florida. Most fish (82%) were recaptured in the initial tagging zone. Water temperature greatly influenced striped bass summer habitat selection and survival.