226 



Fishery Bulletin 89(2). 1991 



(a) Munda 

 £ devisi 



fcUv^ 



MAMJJASONDJFMAMJJASONDJFMAM 



(b) Vona Vona 



1 f f r ^N t 



MAMJJASONDJFMAMJJASONDJFMAM 



(c) Tulagi 



MAMJJASONDJFMAMJJASONDJFMAM 



1987 1988 1989 



Time (months) 



5 



a 



0) 



a. 



E heterolobus 



MAMJJASONDJFMAMJJASONDJFMAM 



T+T 



MAMJJASONDJFMAMJJASONDJFMAM 



/K-K . . 



MAMJJASONDJFMAMJJASONDJFMAM 



1987 1988 1989 



Time (months) 



Figure 5 



Monthly variation in proportion 

 (±95% confidence limits) of 

 female Encrasicholina devisi and 

 E. heterolobus spawning at three 

 sites in the Solomon Islands, 

 March 1987-May 1989. 



similar stage of development. Fish with spent ovaries 

 (Stage 6) were observed but were rare (<1%). 



Archamia zosterophora This species matured at 

 37 mm and was capable of spawning at this length 

 (Table 2, Fig. 4d). A gonosomatic index value greater 

 than 2.5% corresponded with sexual maturity (Table 2). 



Spawning seasons 



All non-parametric tests showed a significant deviation 

 from random spawning for all species at all sites (P< 

 0.05). The distribution of deviations (plus signs) was 

 either clumped or regular. For no species at any site 

 were there significant positive correlations between the 



proportion of larger fish and the proportion spawning 

 (P>0.05). 



Encrasicholina Spawning activity by the two Encra- 

 sicholina species showed both seasonal and interannual 

 variation (Fig. 5). Both species had one or two major 

 peaks in spawning each year. However, the pattern 

 was different each year. Both species had a major peak 

 in spawning activity early in the year (March-May) dur- 

 ing 1987 and 1988, except for E. devisi at Munda in 

 1987 when most fish spawned later (Sept.-Oct.). The 

 peak spawning was usually followed by several months 

 when a small proportion of the population was spawn- 

 ing. Patterns of spawning at Munda and Vona Vona 

 were more similar than at Tulagi. Encrasicholina 



