FISHERY BULLETIN: VOL. 82, NO. 2 



age each month. Analyses excluded several 

 months in which estimates were not reliable be- 

 cause of incomplete recruitment (2 mo, time- 

 specific; 6 mo, cohort-specific), seeming immigra- 

 tion ( 1 mo, time-specific), or some stations were not 

 occupied in one cruise (1 mo, cohort-specific). 

 Pooled estimates of S were calculated using 

 Heincke's procedure (Ricker 1975) and were con- 

 verted to 1 - S and Z using relationships in Gul- 

 land (1969:59). Observed estimates were compared 

 against theoretical values calculated from the ex- 

 pression Z = 4.6/number of years in life span 

 (Royce 1972:238). Typical maximum life span was 

 approximated by the Beverton-Holt yield model 

 parameter t L (Gulland 1969), and typical 

 maximum size was approximated as a correspond- 

 ing length (l/J following Alverson and Carney's 

 (1975) definition that only 0.5-1% of the catch ex- 

 ceeds age tL. Values of li were calculated from the 

 cumulative length frequency for all fish captured 

 in the period October 1977- August 1981. We calcu- 

 lated specific values of ti from l L by solving for 

 time in von Bertalanffy (Gulland 1969:40) and 

 quadratic regression equations. Total mortality 

 rates and growth data presented are termed ap- 

 parent because they may be affected by emigration 

 as noted; if so, they overestimate mortality but 

 underestimate sizes at age. 



Ovaries were prepared to estimate fecundity 

 (FEC) using procedures similar to Bagenal (1957) 

 and Simpson (1959). Entire ovaries of 60 Early 

 Developing, Late Developing, Gravid, or Ripe fish 

 were removed, split, everted, placed in Gilson's 

 solution for 1-3 mo, and agitated using a magnetic 

 stirrer to enhance separation of ova from connec- 

 tive tissue. Connective tissue was removed and 

 supernatant siphoned off until only ova remained. 

 Eggs were then placed in a beaker, filled to 200 ml 

 with water, and magnetically stirred to be uni- 

 formly dispersed. Fecundity was determined for 

 each fish by taking a 2 ml sample from each of 

 three fixed levels in the beaker (at 25, 100, 175 ml) 

 to enumerate eggs. Samples were pooled to calcu- 

 late a mean/2 ml for each fish because, although 

 significant, differences in mean egg count per level 

 over all fish were small (627, 592, and 598, respec- 

 tively; n = 60 for each level). Mean counts/2 ml 

 were expanded to determine fecundity as the 

 number of eggs in the total water volume. 



Regression relationships were calculated fol- 

 lowing standard procedures (Helwig and Council 

 1979; Snedecor and Cochran 1980). Von Ber- 

 talanffy growth was calculated using Fabens' 

 (1965) program. All length measurements pre- 



sented herein are total length unless stated 

 otherwise, and all length frequencies are moving 

 averages of three. Conversions between standard 

 length and total length used regressions presented 

 herein. 



We use the verb "recruit" and the noun "re- 

 cruitment" herein to describe areas in which 

 young L. fasciatus descend to the bottom from 

 their pelagic (Johnson 1978) early stages. This 

 usage conforms to Beverton and Holt's (1957) 

 meaning of recruitment, because these bottom 

 areas are exploited, and to Ricker 's (1975) mean- 

 ing, because fish also then enter the exploited 

 phase of life. 



RESULTS 



Maturation and Spawning Periodicity 



Larimus fasciatus from the northwestern Gulf 

 mature at 80-130 mm as they approach age I. 

 Gonad development was distinct at 80-150 mm 

 when most females entered the Early Developing 

 stage (Fig. 4). All fish in Late Developing and later 

 stages were >130 mm. These data are supported 

 by regressions of ovary weight on length (Fig. 2) in 

 which extrapolated x- intercepts were 75-125 mm 

 during the April-October period when spawning 

 occurs. Age compositions and sizes presented later 

 indicate L. fasciatus mature to first spawn at 

 12-14 mo. 



Little somatic growth seemingly occurs after L. 

 fasciatus enter late stages of gonad development. 

 Mean lengths of fish were 146 mm in the Late 

 Developing stage, 147 mm when Gravid, 149 mm 

 when Ripe and Spawning/Spent, and 150 mm 

 when Resting (Fig. 4). Maximum and minimum 

 sizes also remained constant through these stages. 



Larimus fasciatus spawn within a broad period 

 from April through November. Fish in Ripe or 

 Gravid stages occurred throughout this period 

 (Fig. 5), slopes and elevations of regressions of 

 ovary weight on length generally were highest 

 (Fig. 2), and GSI maximums usually were high 

 (Fig. 3). Gonad analyses are supported by 1) recur- 

 rent collections of fish 20-40 mm from November 

 through February each year in the period 1978-81 

 which probably were 1-3 mo old and indicate 

 spawning from September through November 

 (Fig. 6), and 2) collections of distinct groups offish 

 40-80 mm in the period mid-June through August 

 in 1980 and 1981 which probably were 3-5 mo old 

 and indicate spawning from April through June. 



Little or no spawning of L. fasciatus occurs from 



344 



