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Age, Growth, and Mortality of Spotted Seatrout in Florida Waters
Author(s) -
Murphy Michael D.,
Taylor Ronald G.
Publication year - 1994
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1994)123<0482:agamos>2.3.co;2
Subject(s) - bay , estuary , gompertz function , biology , fishery , fishing , annual growth % , ecology , geography , mathematics , statistics , botany , archaeology
Estimates of age, growth, and mortality of spotted seatrout Cynoscion nebulosus were made by analyzing fish from commercial and recreational catches in 1986–1988 in three estuarine areas of Florida: Apalachicola Bay, Charlotte Harbor, and Indian River Lagoon. Thin sections of sagittae were used to determine age; annulus formation occurred in November–May. The maximum observed age differed among areas, ranging from 5 to 9 years for males and from 6 to 8 years for females. Spotted seatrout reached 301–337 mm total length at the end of their first year. Females were generally larger at age than males, although growth was highly variable. After age 1, male growth slowed to an average of 34–51 mm/year and was modeled best by area‐specific linear growth equations. Females showed asymptotic growth that slowed from 87–107 mm at ages 1–2 to 46–60 mm at ages 4–5 and that was modeled best by area‐specific Gompertz growth equations. Males and females from Indian River Lagoon and Apalachicola Bay were generally larger than those from Charlotte Harbor. Males were heavier than females of the same length. Estimates of total annual mortality were 48–76% in 1986–1988 and seemed highest in Apalachicola Bay. Patterns of growth did not reflect those previously used to support hypothesized divisions of spotted seatrout into separate subpopulations in Florida estuaries. Differences in growth and age composition observed among estuaries may reflect differences in environmental and fishing effects rather than genetic differentiation among estuaries.