WARLEN; AGE AND GROWTH OF LARVAL GULF MENHADEN 



E 

 E 



I 

 (- 



o 



z 



LU 



_l 



Q 



cr 

 < 



Q 



W 



20 



15 



10- 



11 11 12 



1 2 2232221 1 123 11 



114" 



" ' 1 



322 1 1 

 833122 

 1 32 

 212 1 



223 

 121 



10 



20 



30 



40 



Louisiana 

 Feb 1980 



50 



60 



ESTIMATED AGE (days) 



Figure 5. — Growth of larval gulf menhaden collected in the winter 

 1979-80 in the northern Gulf of Mexico. The Gompertz growth model 

 was used to describe the data. Coincident data points are labelled as in 

 Figure 4. 



February in three years. Larvae caught in 1980 

 grew faster than larvae caught in 1981 and 

 larvae caught in 1982 up to 25 days, thereafter 

 1980 and 1982 had very similar size at age esti- 

 mates. 



Louisiana vs. Florida vs. 

 Texas - February 1982 



There were no significant differences 

 (MANOVA, P = 0.212) among the growth curves 

 for larvae caught in February 1982 off Louisiana, 

 Texas, and Florida (Figs. 7c, d, e), and hence no 

 pairwise comparisons were necessary. 



Louisiana vs. Texas - February 

 1981-82 



Statistically significant differences (MAN- 



OVA, P < 0.002) in larval growth were observed 

 in the LA and TX transects from February 1981- 

 82. Pairwise comparisons indicated significant 

 differences (P < 0.008) in the growth of larvae 

 collected off Texas in 1981 (Fig. 6d) and 1982 (Fig. 

 7e) and in growth between LA 1981 (Fig. 6c) and 

 TX 1981 collections. The earlier pairwise com- 

 parisons had already shown a significant differ- 

 ence in growth of larvae from LA February 1981 

 and February 1982 collections (Fig. 7c), but none 

 for growth of larvae caught in the LA February 

 1982 and TX February 1982 collections. Two 

 other potential tests, between transects of differ- 

 ent areas and different years, were not considered 

 to be meaningful. 



Larvae caught off Louisiana in February 1981 

 were larger at age 18+ days than were larvae 

 caught off Texas in February 1981, and might be 

 considered to be faster growing fish. There was a 



83 



