Rajaguru: Biology of Cynoglossus are! and C lida from Indian waters 



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MALE 



STAGE-I 



J FMAMJ JASOND 



MONTHS 



■ C. ARKL 

 B C. LIDA 



STAGE-II 



J FMAMJ JASOND 



MONTHS 



STAGE-HI 



JFMAMJJASOND 



MONTHS 

 Figure 12 



Monthly percentage occurrence of different testis 

 maturity stages in male Cynoglossus arel and C. lida 

 caught commercially off Porto Novo, India, October 

 1981-September 1982. (Refer to Appendix for 

 monthly sample size). 



during all stages of maturity, only ova >0.11mm were 

 taken into consideration, from Stage II onwards. Pro- 

 gressive maturation to spawning condition was evident 

 from increasing ova diameters of the most advanced 

 mode at each stage. 



For C. arel (Fig. 13) in Stage I, maximum number 

 of ova measured 0.01-0.04 mm; however, a few rela- 

 tively larger ova (0.09-0.11 mm) were also recorded. 

 In Stage II, a mode was discernible with a stock of ova 

 (0.16-0. 19mm) separated from immature stock. In 

 Stage III, the previous mode (at 0.16-0. 19 mm) shifted 

 to 0.24-0.26 mm. In Stage IV, a mode made by opaque 

 ova was observed at 0.36-0.38 mm. In Stage V, two 

 modes were found, one with a peak at 0.43-0.45 mm, 

 and another at 0.50-0.53 mm. In Stage VI, the pre- 

 ceding two modes formed jointly a single mode, with 

 fully mature, transparent, and large-sized ova of 

 0.54-0.56 mm. 



For C. lida (Fig. 13) in Stage I, immature ova mea- 

 sured 0.01-0.04 mm. In addition, a few relatively larger 

 ova (0.09-0.11 mm) were also seen. In Stage II, a mode 

 was discernible with a stock of ova at 0.09-0.11 mm, 

 which was separated clearly from immature ova. In 

 Stage III, the previous mode was shifted to 0.20-0.23 

 mm. In Stage IV, a mode of opaque ova was located 

 at 0.31-0.34 mm. In Stage V, a mode of ripe ova was 

 noted at 0.35-0.38 mm. In Stage VI, fully mature, 

 transparent, and large-sized ova formed a mode at 

 0.39-0.41 mm. 



Results indicate that individuals of C arel and C. lida 

 spawn only once during each season. Further, mature 

 modes were wide-based (0.49-0.83 mm in C. arel, and 

 0.34-0.64 mm in C. lida); therefore, the spawning 

 period of these species must be extended. 



Gonadosomatic Index In male C. arel (Fig. 14), the 

 highest GSI peak was in March, and the lowest GSI 

 value was observed in January. In female C. arel (Fig. 

 14), the highest GSI peak was observed in November, 

 and the lowest value was in January. In both sexes of 

 C. arel, the peak values of GSI did not correspond with 

 the observed spawning period in that year. 



In male C. lida (Fig. 14), the highest GSI peak 

 occurred in September, and the lowest value was in 

 January, November, and December. In female C. lida 

 (Fig. 14), the highest GSI peak was observed in May, 

 while the lowest value was in December. Only in male 

 C. lida did the high GSI peak coincide with the observed 

 peak spawning period in September. 



Ova diameter Ova diameter frequencies, from ova- 

 ries of Stage I-VI, are shown in Figure 13 for C. arel 

 and C. lida. Since immature, transparent, and micro- 

 scopic ova (< 0.11 mm) outnumbered the maturing ova 



Relative condition factor (Kn) In male C. arel (Fig. 

 14), the highest Kn value peak was observed in Feb- 

 ruary, and the lowest value was in October. In female 

 C. arel (Fig. 14), the highest Kn peak was observed in 

 January, and the lowest value was in November. Only 



