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Age, growth, and reproduction of gag, Mycteroperca microlepis (Pisces: Serranidae), in the eastern Gulf of Mexico
Hood, P.B.; Schlieder, R.A. (1992). Age, growth, and reproduction of gag, Mycteroperca microlepis (Pisces: Serranidae), in the eastern Gulf of Mexico. Bull. Mar. Sci. 51(3): 337-352
In: Bulletin of Marine Science. University of Miami Press: Coral Gables. ISSN 0007-4977, more
Peer reviewed article  

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Keywords
    Age; Biological age; Growth; Growth curves; Life history; Otolith reading; Reproduction; Reproductive cycle; Seasonal variations; Sex ratio; Sexual maturity; Sexual reproduction; Mycteroperca microlepis (Goode & Bean, 1879) [WoRMS]; Pisces [WoRMS]; Serranidae Swainson, 1839 [WoRMS]; Marine

Authors  Top 
  • Hood, P.B.
  • Schlieder, R.A.

Abstract
    A total of 1,331 gag, Mycteroperca microlepis, captured in the eastern Gulf of Mexico from November 1977 to May 1980 were sampled for life history analysis. Gag captured in waters less than 30 m deep by commercial and nearshore recreational fishermen were significantly smaller (T-L- less than or equal to 739 mm) than those captured in greater depths (T-L-) greater than or equal to 832 mm). Analyses of marginal increments, annulus spacing, and the relationship of otolith size to fish length suggested that a ring forms on the sagittae once each year during the summer. Growth of gag was greatest during the first 10 years, after which mean size approached an apparent maximum of about 1,100 mm TL. Estimates of the von Bertalanffy growth equation parameters (standard error) for gag were as follows: L sub( infinity ) = 1,190 mm TL (22 mm), K = 0.166 (0.009), and t sub(o) = -0.62 (0.13). Growth rate estimates determined from monthly length-frequency data for juveniles and from historical tagging data for adults agreed with the estimate determined by analyzing otolith sections. Gag are protogynous hermaphrodites, and females in the sample outnumbered males 6:1. Females became mature between ages III and VI, and no males less than age V were observed. Histological and gravimetric analyses of gonad condition suggested that gag spawn from December to May, with peak activity occurring during February and March.

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