SOME STUDIES ON REPRODUCTIVE BIOLOGY OF SOL (CHANNA MARULIUS) IN THE PUNJAB, PAKISTAN

Abstract

Sol (Channa marulius) is a good target species for introduction into the aquaculture system of Pakistan, being indigenous and having potential to survive under variety of stressful freshwater conditions. The present study has been undertaken to study the growth and reproductive biology of the species under the conditions of Punjab (Pakistan). The analysis of morphometric and meristic characters suggested a significant correlation between the morphometric characters and a non-significant correlation between meristic characters, suggesting that meristic characters have a higher taxonomic value. Principal Component analysis suggested that fishes of different sizes have different patterns of growth of recorded variables. The fish with an average size of 7.37 cm (2.88g) increased to 53.8 cm (1165.7 g) from the age of 2 months to the age of 16 months. The fish at different ages suggested an isometric growth of weight in relation to length, with an average regression coefficient value of 3.05. Analysis of different reproductive biology variables conducted on fish captured from wild conditions suggested that the condition factor, gonadosomatic index (GSI), levels of progesterone and testosterone started gradually increasing after December, reaching peak values in April and a sudden decline in May. However, estrdiol peaked in March and showed minimum level in June. Hepatosomatic index (HSI) showed an inverse pattern, showing a decline in December with minimum values in May, when it started increasing to maximum values in the later part of the year. The pattern of histological changes in gonads followed the pattern of other variables of reproductive biology indicating that these variables truly represent the reproductive state of the individual. The studies suggest that the species is a long day species, where the reproductive activities commence after December and spawning takes place between late march and early May, under the environmental conditions of the Punjab (Pakistan).