224 



Fishery Bulletin 89(2). 1991 



ll 



MAMJJASONDJFMAMJJASONDJFMAM 

 1987 1988 1989 



Time (months) 



Figure 1 



Mean monthly sea temperature and rainfall at 

 Munda, Solomon Is., March 1987-May 1989. 



(J 



MAMJJASONDJFMAMJJASONDJFMAM 

 1987 1988 1989 



Time (months) 



Figure 3 



Mean monthly sea temperature and rainfall at 

 Tulagi, Solomon Is.. March 1987-May 1989. 



600 

 -p 500 



w 400 



MAMJ JASONDJFMAMJ JASONDJ FMA 

 1987 1988 1989 



Time (months) 



Figure 2 



Mean monthly sea temperature and rainfall at 

 Vona Vona, Solomon Is.. March 1987-May 1989. 



In both Encrasicholina species, fish with a GSI 

 greater than 2% (Table 2) were sexually mature. The 

 size at maturation of E. devisi was similar at all sites 

 with 50% of the fish being sexually mature at 44-45 mm 

 (Fig. 4a). At Munda and Vona Vona, fish beyond this 

 length were capable of spawning, but at Tulagi the 

 smallest E. devisi in spawning condition was 52 mm 

 (Table 2). Sexual maturity in E. heterolobus was 

 reached at approximately 43 mm at Munda and Vona 

 Vona (Fig. 4b) and 45 mmat Tulagi. Hydrated eggs 

 were not observed in E. heterolobus less than 50 mm, 

 except at Munda where the smallest potential spawner 

 was 45 mm (Table 2). 



Spratelloldes The three Spratelloides species at the 

 three sites were mature at similar lengths. Spratel- 

 loides gracilis and S. lewisi were sexually mature and 

 had hydrated eggs at 35 mm (Table 2, Fig. 4c), except 

 at Tulagi where the smallest S. lewisi with running ripe 

 eggs was 40 mm. Spratelloides delicatulus reached sex- 

 ual maturity at 37 mm (Fig. 4d), and running- ripe eggs 

 were found in fish beyond this length. However, their 

 length-at-maturity was not significantly different from 

 the other Spratelloides species (P>0.1). For all species, 

 a gonosomatic index of over 2% correlated with fish 

 having ripe eggs (stage 4) in the ovary. Most oocytes 

 in the ovaries of females of these species were at a 



