199 



Abstract.-Sagittae (n=2,263) and 

 gonads (?i=870) from snowy grouper, 

 Epmephelus nireatus, caught primar- 

 ily with longlines. Kali poles, snapper 

 reels, and chevron traps ofT North Caro- 

 lina and South Carolina were examined 



1) to compare growth rates, population 

 age structure, and sex ratio between 

 two periods 1979-85 and 1993-94, and 



2) to determine reproductive seasonal- 

 ity, size and age at maturity, and size 

 and age at sex change. There were sev- 

 eral indications that the population off 

 North Carolina and South Carolina is 

 overfished; 1 ) size at age of specimens 

 caught with longlines and snapper reels 

 has increased noticeably since the 1980s 

 (possibly a a density-dependent popula- 

 tion response to a high level of fishing 

 mortality ); 2 ) 8 1'^f of the fish caught with 

 commercial longlines during 1993-94 

 were ages 1-6. the majority (SB*?) of 

 which were immature females; 3) the 

 percentage of males in the population 

 appears to have decreased significantly, 

 from 7-23<7f in the 1970s and 1980s to 

 1% in the 1990s; and 4) mean length 

 of fish landed in the longline fishery 

 has steadily decreased from 65-80 cm 

 in the early 1980s to 50-60 cm in the 

 mid-1990s. There was a positive trend 

 between water depth and total length 

 in fishery-independent samples. Histo- 

 logical examination of gonads revealed 

 that mature gonads were present in 4% 

 of the females at age 3, 52*^ at age 

 5, 95*7^ at age 7, and 1007c at ages >7 

 during 1993-94. The smallest mature 

 female was 469 mm TL, and the larg- 

 est immature female was 575 mm. Esti- 

 mates of Lengthjy and Age^^ were 541 

 mm (95'» CI=529-553 mm) and 4.92 

 yr OS'/f CI=4.65-5.21 yr), respectively. 

 Spawning females were caught during 

 April through September on the upper 

 continental slope off South Carolina at 

 depths of 176-232 m. The size ( 767-1090 

 mm I and age i8-29 vr) of 97 male speci- 

 mens and the capture of two specimens 

 undergoing sex change provided conclu- 

 sive evidence that snowy grouper are 

 protogynous hermaphrodites. 



Growth, population age structure, 

 and aspects of the reproductive biology 

 of snowy grouper, Epinephelus niveatus, 

 off North Carolina and South Carolina* 



David M. Wyanski 

 D. Byron White 

 Charles A. Barans 



South Carolina Department of Natural Resources 



Marine Resources Research Institute 



RO Box 12559 



Charleston, South Carolina 29422 2559 



E-mail address (for D M Wyanski) wyanskidiamrd.dnrstate.sc.us 



Manuscript accepted 26 August 1999. 

 Fish. Bull. 98; 199-2 18 12000). 



The snowy grouper, Epinephelus 

 niveatus, is a commercially impor- 

 tant deepwater species that occurs 

 in the western Atlantic from North 

 Carolina (Cape Hatteras) to Brazil, 

 including the Gulf of Mexico and 

 the Bahamas (Smith, 1971). It also 

 occurs in the eastern Pacific from 

 California to Mexico (Miller and 

 Lea, 1976; Fitch and Schultz, 1978 ). 

 Along the coast of the southeast 

 United States, adult snowy grou- 

 per are predominantly found on the 

 upper continental slope ( >75 m; Lee 

 et al., 1985) at depths of 116-259 m 

 (Low and Ulrich, 1983; Moore and 

 Labisky, 1984; Parker and Ross, 

 19861, whereas juveniles are more 

 common at shallower depths ( Moore 

 and Labisky, 1984). Low and Ulrich 

 (1983) noted a positive correlation 

 between total length (TL) and water 

 depth off South Carolina. Most fish- 

 ing for this species occurs in habi- 

 tats characterized by rocky ledges, 

 cliffs, and swift currents (Matheson 

 and Huntsman, 1984). 



Snowy grouper are captured pri- 

 marily in commercial fisheries of the 

 southeastern United States ( Parker 

 and Mays, 1998). Most are caught 

 with bottom longlines and snapper 

 reels^ (handlines). Starting in 1991, 

 the longline fishery was restricted 

 to waters deeper than 91 m by the 

 South Atlantic Fishery Management 



Council (SAFMC, 1991). Fishing 

 for snowy grouper has occurred off 

 North Carolina and South Caro- 

 lina (the Carolinas) since the mid- 

 1950s (Huntsman, 1976); annual 

 landings from the Carolinas aver- 

 aged 119,657 kg during 1981-96 

 (Moran-). According to the spawn- 

 ing stock ratio (SSR), the popula- 

 tion off the Atlantic coast of the 

 United States is considered to be 

 overfished (SAFMC, 1993). 



Population age structure and 

 individual growth rates in the 

 snowy grouper population have not 

 been assessed since the mid-1980s 

 and should be assessed again given 

 the sustained fishing pressure on 

 the population. Studies of other 

 fish populations have shown that 

 size at age is often affected by the 

 level and duration of exploitation 

 ( Haug and Tjemsland, 1986; Harris 

 and McGovern, 1997; Helser and 



Contribution 430 of the South Carolina 

 Manne Resources Center, P.O. Box 12559. 

 Charleston, SC 29422. 



' Snapper reels are commonly known as '1)an- 

 dits" or "one-armed bandits' by fishermen 

 owing to the remote similarity between early 

 snapper reels and gambling slot machines, 

 and because luck is involved in what is 

 caught. The early mechanical reels have 

 typically been replaced by 12 volt DC auto- 

 mobile starter motors or hydraulic systems. 



- Moran.J. 1996. S. Carolina Dept. of Nat- 

 ural Resources, P.O. Box 12559, Charleston, 

 SC 29422. Personal commun. 



