Growth and morphology of 

 larval and juvenile captive bred 

 yellowtail snapper, 

 Ocyurus chrysurus* 



Cecilia M. Riley 

 G. Joan Holt 

 Connie R. Arnold 



Marine Science Institute 



The University of Texas at Austin 



RO. Box 1267, Port Aransas, Texas 78373 



The snappers (Lutjanidae) are ma- 

 jor components of the reef fish fish- 

 ery in the Gulf of Mexico (Naka- 

 mura, 1976), and recent declines in 

 their populations have prompted 

 interest in a number of manage- 

 ment practices including limited 

 catches, size limits, area closures, 

 and additions of artificial reef habi- 

 tat to improve survival of wild 

 stocks (Leis, 1987; Munro, 1987). 

 Studies on the spawning, distribu- 

 tion, larval and juvenile ecology, 

 and stock assessment of new re- 

 cruits are crucial to the develop- 

 ment of management strategies for 

 reef species since little is known 

 about their early life history 

 (Grimes, 1987). During most devel- 

 opmental stages, snapper larvae 

 are pelagic and widely dispersed, 

 limiting the numbers of specimens 

 to be found in taxonomic collections 

 (Munro, 1987). The similarity in 

 size and pigmentation of small lar- 

 val lutjanids (<5 mm) and the pau- 

 city of species-specific details of size 

 at age and morphological develop- 

 ment has made identification of in- 

 dividuals in ichthyoplankton 

 samples difficult (Leis, 1987). Of the 

 fourteen species of snappers that are 

 found in the Gulf of Mexico, 1 larval 

 development has been fully described 

 for only three species: red snapper, 

 Lutjanus campechanus , from both 

 laboratory spawned (Rabalais et al., 



1980) and wild caught larvae (Collins 

 et al., 1980); gray snapper, L. griseus, 

 from wild eggs reared in the labora- 

 tory (Richards and Saksena, 1980); 

 and vermilion snapper, Rhomboplites 

 aurorubens, from wild preserved 

 specimens (Laroche, 1977). A recent 

 NOAA report by Richards et al. 2 

 summarizes the larval lutjanid de- 

 scriptions listed above and intro- 

 duces some newly available descrip- 

 tive material for several additional 

 species of snappers including some 

 stages of yellowtail snapper, Ocyurus 

 chrysurus. In their report, the yellow- 

 tail snapper is included in the genus 

 Lutjanus, a change suggested as a 

 result of two recent treatments by 

 Loftus ( 1992) and Domeier and Clark 

 (1992). 



The commercial and recreational 

 importance of snappers has also 

 been recognized by the aquaculture 

 industry, and efforts are underway 

 to culture several of these species 

 in captivity. In this paper we de- 

 scribe the development and growth 

 of laboratory spawned and reared 

 yellowtail snapper. This species is 

 found from Massachusetts through 

 the Caribbean and south to Brazil 

 (Hoese and Moore, 1977). Labora- 

 tory culture allowed us to document 

 growth and development of the 

 critical larval and juvenile stages 

 of yellowtail snapper that will aid 

 identification and ageing of larval 



snappers collected in the field. We 

 have also included information on 

 the effects of a commonly used pre- 

 servative (ethyl alcohol) on length 

 measurements and pigmentation 

 characteristics of laboratory-cul- 

 tured larvae for purposes of compara- 

 tive use with wild-collected larvae. 



Materials and methods 



Young adult Ocyurus chrysurus were 

 collected by hook and line in July 

 1990 from the Florida Keys and were 

 transported to the laboratory where 

 they were matured and cycled for one 

 year following the methods described 

 by Arnold (1988). Adults began 

 spawning in July 1991 and contin- 

 ued to March 1994. 



Eggs were stocked at a density 

 of 50/L in fiberglass tanks (300 and 

 600 L) with internal biofilters. Lar- 

 vae were reared at 27-28°C with 12 

 hours light at salinities of 33-38 

 ppt on a diet of zooplankton (col- 

 lected from the Corpus Christi Ship 

 Channel), rotifers (Branchionus 

 plicatilis) and brine shrimp nauplii 

 (Artemia salina). 



The description of larval devel- 

 opment is based on larvae from 

 multiple spawns of two different 

 groups of broodstock (15 adults/ 

 tank). Larvae were measured live 

 (SL=tip of snout to posterior tip of 

 notochord) to the nearest 0.01 mm 

 on a stereomicroscope equipped 

 with a drawing tube and digitizing 



* Contribution 907 of the Marine Science 

 Institute, University of Texas at Austin. 



1 Lyczkowski-Shultz, J., and B. H. Comyns. 

 1992. Early life history of snappers in 

 coastal and shelf waters of the 

 northcentral Gulf of Mexico (late summer/ 

 fall months, 1983-1989). Final Rep. to 

 MARFIN, NA90AA-H-MF730. 



2 Richards, W. J., K. C. Lindeman, J. L. 

 Shultz, J. M. Leis, A. Ropke, M. E. Clark, 

 and B. H. Comyns. 1994. Preliminary 

 guide to the identification of the early life 

 history stages of lutjanid fishes of the 

 western central Atlantic. U.S. Dep. 

 Commer., NOAA Tech. Memo. NMFS- 

 SEFSC-345, 49 p. 



Manuscript accepted 29 August 1994. 

 Fishery Bulletin 93:179-185 (1995). 



179 



