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Fishery Bulletin 98(3) 



Materials and methods 



A total of 96 reared larvae, ranging in body length (BL) from 

 1.9 to 26.1 mm, and a total of 118 wild larvae, ranging from 

 2.6 to 20.0 mm BL, were used to describe larval development 

 of red snapper. Reared larvae came from the Marine Sci- 

 ence Laboratory, University of Texas at Austin, Port Aran- 

 sas, Texas ( TX). and the Claude Peteet Mariculture Center in 

 Gulf Shores, Alabama ( AL). Spawning and rearing methods 

 used are described by Riley et al. ( 1995) at the Texas facility 

 and by Bootes ( 1998) at the Alabama facility. Notable differ- 

 ences in the rearing methods at the two facilities that could 

 have contributed to different developmental rates include 

 higher salinities in the TX study (33-38 ppt vs. 31-33 ppt), 

 higher temperatures in the AL study (27-32°C vs. 27-28°C ) 

 and natural light conditions in the AL study. Several larvae 

 were preserved each day during the Texas rearing study 

 whereas only one larva was preserved each day during the 

 Alabama rearing experiments. Specimens from AL were 

 fixed in 2'7f formalin and specimens from TX were fixed in 

 80*^ ethanol (EtOH) and together formed the developmen- 

 tal series described in our study. Age in days after hatching 

 (DAH) is included in parentheses after BL for reared larvae. 

 In addition, observations on the development of pigment 

 characters were augmented with 96 larvae reared at the 

 Gulf Coast Research Laboratory iGCRL) in Ocean Springs, 

 MS, under conditions similar to the AL study. 



Wild red snapper larvae were obtained from plankton 

 samples collected in the GOM by the Southeast Area Mon- 

 itoring and Assessment Program (SEAMAP) and GCRL. 

 Samples were collected with bongo and neuston nets at 

 stations 56 km apart by using standard SEAMAP collec- 

 tion procedures (Richards, 1984; Richards et al., 1993). 

 Samples were fixed in lO'/r formalin and transferred to 

 70% EtOH after 48 h. 



All specimens described in our study are considered 

 larvae because they exhibit specializations for pelagic life 

 (head spination. long fin elements) and are pigmented dif- 

 ferently than juveniles and adults are pigmented (Leis. 

 1987; Leis and Trnski, 1989; Leis et al., 1997). Myomere 

 and fin-ray counts were made on the left side of the body. 

 Illustrations were made with a camera lucida. Preserved 

 eggs and larvae were measured to the nearest 0.1 mm with 

 an ocular micrometer fitted to a dissecting microscope. 

 Body length (BL) as defined in Leis and Rennis (1983) is 

 equivalent to notochord length or standard length depend- 

 ing on the stage of development of the larvae. Notochord 

 length is the straight line distance from the tip of the snout 

 to the posterior tip of the notochord and is used as the 

 standard measurement before and during flexion. Stan- 

 dard length is the distance from the tip of the snout along 

 the midline to a vertical line through the posterior edge 

 of the hypural plate. Other common measurements and 

 abbreviations follow Leis and Rennis (1983). Additional 

 abbreviations used here are as follows: 



avm = anterior surface of the visceral mass; 

 BD = body depth; 



IPo = inner border of the preopercle (=anterior border of 

 some authors); 



OPo = outer border of the preopercle ( =posterior border 



of some authors); 

 pav = postanal-ventral. 



Results 



Description of reared larvae 



General development (Table 1, Figs. 1-5) Red snapper 

 eggs (AL) were 0.72-0.76 mm in diameter (n=4) atone hour 

 after fertilization and contained a single oil globule (diam- 

 eter 0.11-0.13 mm). Larvae hatched in approximately 24 

 h and had a large, elongate yolk sac extending anteriorly 

 beyond the head with a single oil globule. The oil globule 

 was the last portion of the yolk to be absorbed at 4 days 

 after hatching ( DAH ). Body lengths of the youngest larvae 

 measured were 1.9 mm at hatching [n = l}, 2.5 mm at 12 h 

 (n=l). and 2.8 mm at 28 h (/! = 1). The eyes were pigmented 

 and the mouth was functional by the end of 2 DAH when 

 larvae began to swim actively and feed. Larvae were ini- 

 tially elongate (lO'/f BD at 2.9 mm) but became deeper 

 bodied {439t BD at 4.9 mm) and laterally compressed with 

 development. The smallest larvae (2.5-3.1 mm) showed no 

 fin development or spination. Head length increased from 

 dVr BL in preflexion larvae (2.4 mm) to 42'7f BL in postflex- 

 ion larvae (7.5 mm). Teeth appeared along the premaxilla 

 and dentary by 3.5 mm. The gut was initially straight but 

 began to coil at 2.4 mm (6 DAH) and was fully coiled by 3.6 

 mm (9 DAH). Preanal length increased from 38'7f BL (2.4 

 mm) in preflexion larvae to 697? BL in postflexion larvae 

 (16.5 mm). Gas bladder inflation occurred at 4 DAH, and 

 in our study the gas bladder was visible in the 2.4-mm (6 

 DAH) larva. Notochord flexion began at 3.8 mm (12 DAH) 

 and was complete by 5.5 mm ( 15 DAH). Scales were pres- 

 ent on the largest specimen (26.3 mm, 34 DAH). 



Spination (Figs. 1 -5) All spines described here were easily 

 visible without clearing and staining. Head spination 

 began by 3.0 mm with the development of preopercular 

 spines, with one spine on the inner border of the preoper- 

 cle (IPo) and two spines (including the angle spine) on 

 the outer border of the preopercle (OPo). At 3.6 mm, there 

 were two spines on the IPo and four spines on the OPo, 

 one above the angle spine and two below. Spines increased 

 to three on the IPo and five on the OPo by 3.8 mm. At 5.6 

 mm, there were four spines on the IPo and six spines on 

 the OPo, four below and one above the angle. Spines on the 

 IPo increased to six by 12.2 mm, and on the OPo increased 

 to eight with six below and one above the angle. Spines on 

 the preopercle in the two largest specimens were smaller 

 (reduced in size) and more numerous than in smaller spec- 

 imens. One interopercular spine was observed between 

 the angle spine and the upper OPo spine by 3.5 mm and 

 was present throughout the rest of the series. An opercu- 

 lar spine was present by 4.4 mm and a postcleithral spine 

 was present just above the pectoral-fin base by 9.6 mm. 

 One supracleithral spine formed by 3.6 mm on the 9-DAH 

 specimen and two supracleithral spines were present on 

 the 3.6-mm (10-DAH) specimen. There were three supra- 



