REPRODUCTIVE BIOLOGY OF 



THE BLUELINE TILEFISH, CAULOLATILUS MICROPS, OFF 



NORTH CAROLINA AND SOUTH CAROLINA 1 



Jeffrey L. Ross 2 and John V. Merriner' 



ABSTRACT 



Blueline tilefish, Caulolatilus microps, were obtained by hook and line fishing and port sampling operations 

 off North Carolina and South Carolina from 1972 to 1977. Caulolatilus microps spawn off the Carolinas from 

 April through October, with peak activity off North Carolina in May-June and September-October. Multiple 

 spawnings by individual females were indicated by multimodel size distributions of ova; this is complement- 

 ed by the continuous production of spermatozoa in testes, which is facilitated by dynamic spermatogenic 

 tubules. Fecundity is best predicted by fish weight: In Fecundity = 0.016 + 1.832 In Weight. Fecundity 

 estimates ranged from 0.2 million ova for a 4 12 mmTL (0.82 kg) fish to 4.1 million ova for a 736 mm TL (4.85 

 kg) fish. Females attained sexual maturity between 425 and 450 mm TL (age IV- V). Males showed pronounc- 

 ed testicular development after age V (500 mm TL). Females were more abundant from 300 to 500 mm TL; 

 the sex ratio was 1 : 1 between 500 and 600 mm TL; males predominated in size classes greater than 600 mm 

 TL. Protogynous sex reversal in three juvenile specimens (156-202 mm TL) was indicated by transitional 

 gonads or testes with residual oocytes. Previtellogenic oocytes in 8 of 42 mature males (436-700 mm TL) 

 further suggest protogyny, although no adult fish with transitional gonads were observed. Whether blueline 

 tilefish are strictly juvenile or functional hermaphrodites has yet to be determined. 



The blueline tilefish, Caulolatilus microps Goode and 

 Bean, is a semitropical demersal branchiostegid that 

 constitutes a significant component of the deepwater 

 grouper- snapper fishery off North Carolina and 

 South Carolina (Huntsman 1976). It inhabits the 

 outer continental shelf, shelf edge, and upper slope 

 (70-235 m) from Cape Charles, Va., to Key West, 

 Fla., and in the Gulf of Mexico from Pensacola, Fla., 

 to Campeche, Mexico (Dooley 1978). 



In 1972 scientists at the Southeast Fisheries Center 

 of the National Marine Fisheries Service (NMFS) 

 began studying the biology, community relation- 

 ships, and population dynamics of the offshore 

 demersal (reef) fishes off the southeastern United 

 States, ultimately to provide effective management 

 of this fishery (Huntsman 1976). The reproductive 

 biology of blueline tilefish was investigated as part of 

 that program, and is herein described with respect to 

 1) spawning seasonality, 2) descriptive gonado- 

 genesis, 3) fecundity, 4) age/size of sexual maturity, 

 5) sex ratio with size, and 6) sexual transition. 



'Contribution No. 1083, Virginia Institute of Marine Science, 

 Gloucester Point, Va. Based on a thesis by Jeffrey L. Ross, submit- 

 ted to the School of Marine Science, College of William and Mary', 

 Williamsburg, Va., December 1978. 



! Virginia Institute of Marine Science, Gloucester Point, Va.; pre- 

 sent address: North Carolina Division of Marine Fisheries, P.O. Box 

 967, Manteo, NC 27954. 



3 Virginia Institute of Marine Sciences, Gloucester Point, Va.; pres- 

 ent address: Southeast Fisheries Center Beaufort Laboratory, 

 National Marine Fisheries Service, NOAA, Beaufort, NC 28516. 



The reproductive biology of C. microps is previously 

 undescribed. Dooley (1978) reported the capture of 

 ripe females in January and May through September 

 off North Carolina. Brief notes on reproduction for 

 other branchiostegids suggest protracted spawning 

 seasons for C. princeps (Fitch and Lavenberg 1971), 

 C. affinis (Dooley 1978), Lopholatilus chameleon- 

 ticeps (Freeman and Turner 1977; Grimes 4 ), and 

 Branchiostegus japonicus japonieus (Hayashi 1977). 

 Dooley and Paxton (1975) related the presence of 

 several size classes of ova in maturing/3, wardi and/?. 

 serratus to multiple spawning and found anomalous 

 sex ratios within size classes. Pelagic eggs and larvae 

 of Caulolatilus sp. andL. chameleonticeps have been 

 collected off the Carolinas and in the northwest 

 Atlantic (Freeman and Turner 1977; M. Fahay 5 ). 



MATERIALS AND METHODS 



Blueline tilefish were captured over rugged pre- 

 cipitous bottoms as well as gently sloping sections of 

 the shelf edge (Fig. 1). Specimens were obtained by 

 hook and line fishing with electric reels and rods from 



Manuscript accepted November 1982. 

 FISHERY BULLETIN: VOL. 81, NO. 3, 1983. 



4 Churchill B. Grimes, Assistant Professor, Department of Environ- 

 mental Resources, Rutgers University, P.O. Box 231, New Bruns- 

 wick, NJ 08903, pers. commun. February 1982. 



'Michael Fahey, Fishery Biologist, Northeast Fisheries Center 

 Sandy Hook Laboratory, National Marine Fisheries Service, NOAA, 

 Highlands, NJ 07732, pers. commun. February 1982. 



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