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Age, Growth, Mortality, and Reproductive Biology of Red Drums in North Carolina Waters
Author(s) -
Ross Jeffrey L.,
Stevens Tonya M.,
Vaughan Douglas S.
Publication year - 1995
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(1995)124<0037:agmarb>2.3.co;2
Subject(s) - fish measurement , estuary , biology , fish <actinopterygii> , otolith , fishery , growth curve (statistics) , zoology , mathematics , econometrics
Red drums Sciaenops ocellatus were sampled in North Carolina waters from October 1987 through December 1990. Ages determined from sectioned otoliths were validated by length‐frequency and marginal‐increment analyses, and the recapture of oxytetracycIine‐marked fish. Fish growth was rapid during the first 5 years, after which annual growth increments were much smaller. Growth was best described by a continuous double von Bertalanffy growth curve, with a transition age of 4.4 years; K 1 , the growth coefficient for fish younger than the transition age, was 0.30/year and K 2 , the growth coefficient for fish older than the transition age, was 0.07/year. Maximum observed age and size were 56 years and 1,250 mm fork length (FL) for males and 52 years and 1,346 mm FL for females. Fifty‐percent maturity was attained among males by age 2 at 621–640 mm FL and among females by age 3 at 801–820 mm FL. Spawning occurred from August through early October in estuarine waters of Pamlico Sound and nearshore ocean waters close to barrier island inlets. Commercial and recreational landings increased during the 1980s, with most of the harvest composed of immature, age‐ I fish caught during the fall. Unadjusted annual return rates (18–25%) for tagged juveniles were high. Annual survival rates based on tag–recapture data were only 6–24%, and estimates of instantaneous total mortality rates ( Z ) from cohort‐based catch curves were 1.56–2.88 for the 1985–1988 year‐classes. The relative abundance of 20–55‐year‐old red drums has declined 90% since 1968–1972.