FISHERY BULLETIN: VOL. 82, NO. 2 



negligible even then. Although two fall-spawned 

 groups, represented by young-of-the-year and age 

 I fish, often were captured, only one predominated 

 in any month except in July 1981 when fish ap- 

 proaching age II were abundant but disappeared 

 thereafter. Once fully recruited, each fall-spawned 

 group predominated to age I and then nearly dis- 

 appeared as the next fall group began to recruit. 



Larimus fasciatus is not abundant after 12 mo of 

 age in the northwestern Gulf and reaches only 

 21-23 mo there. Fall-spawned fish were abundant 

 after 12 mo of age (Fig. 6) only in July 1981 when 

 they approached age II. Fall-spawned groups dis- 

 appeared at 15-23 mo of age (Table 5, Fig. 6). The 

 few spring-spawned fish captured were identifi- 

 able only until 3-5 mo of age (Table 5, Fig. 6). Fish 

 of intermediate size between clearly defined fall- 

 spawned groups in January and March 1980 and 

 February 1981 could have been spring-spawned, 

 but their identity is not clear. 



Slightly larger L. fasciatus occur in the north 

 central Gulf than in the northwestern area. 



(Harding 1949), moreover, do not and cannot re- 

 solve this situation because of the original prob- 

 lem: the underlying length frequency is not abso- 

 lutely clear. However, the 48 mm range of sizes 

 (139-187 mm) for fish in the north central Gulf is 

 only slightly larger than a 35 mm range (130-165 

 mm) that tightly brackets most fish in the north- 

 western Gulf where only one fall group predomi- 

 nated (Fig. 11). Moreover, sizes in the north central 

 Gulf in the period October-November were only 

 slightly larger than and greatly overlap those for 

 northwestern Gulf fish which were just age I. 

 These facts suggest only one or at most two 

 spawned groups predominated in the north cen- 

 tral Gulf, fish just age I and age II. This interpreta- 

 tion is supported by our findings noted later that 1) 

 the largest fish we captured in the northwestern 

 Gulf (182 mm) was only 20 mo old, 2) von Ber- 

 talanffy predictions indicated mean sizes of 164 

 and 181 mm at age II in the northwestern Gulf 

 depending upon variation between fall-spawned 

 groups, and 3) the observed size range was 143-176 



Maximum and mean sizes were greater in the 

 north central Gulf (max. = 187 mm, x = 160 mm) 

 than in the northwestern area (max. = 173, x = 

 146) during the period October and November, ig- 

 noring the seven recently hatched recruits cap- 

 tured in the latter area (Fig. 11). 



Only one or two spawned groups of L. fasciatus 

 apparently predominate in the north central Gulf, 

 probably fish that became age I and age II in the 

 fall. We are not able to confidently identify modal 

 groups to assign ages and, particularly, delineate 

 sizes where age groups overlap in that area (Fig. 

 11), because we made only one cruise there, not the 

 time-intensive series that permits confident age 

 designations for the northwestern Gulf. Analyses 

 such as linear transformation of cumulative per- 

 centage frequencies using probability paper 



30 



20 



> 



O 10 

 z 

 111 



§ ° 



111 



Northwestern Gulf 



n = 414 x = 146 mm 



s 2 = 144.28 



Recently Hatched 

 I 1 



North Central Gulf 



n 64 x = 160 mm 



s 2 = 141.61 



i (?) ii 

 i 1 1 1 



^W^Vy. 



40 80 120 160 



TOTAL LENGTH (mm) 



200 



FIGURE 11. — Length frequencies and age designations for all 

 Larimus fasciatus captured in the period October-November in 

 the northwestern (1977-80) and north central (1982) Gulf of 

 Mexico. Means, n, and s 2 ignore seven recent recruits (< 70 mm) 

 in the northwestern Gulf. 



354 



