STUDY ON THE REPRODUCTIVE BIOLOGY OF VIETNAMESE CLIMBING PERCH (Anabas testudineus)

Abstract

In order to know the reproductive biology it is necessary to investigate about the developmental changes in macroscopic and microscopic features of the ovary and testes of female and male Vietnamese Climbing Perch, A. testudineus. The study was conducted in post graduate laboratory of Dept. of Fish Biology and Genetics at Sylhet Agricultural University, Sylhet over a twelve months study period to know the reproductive biology which includes GSI, HSI, fecundity, macroscopic and microscopic observation of gonads. The sample was collected monthly from the nearest pond of the University. The ovarian and testicular development were inspected macroscopically and microscopically to know the spawning season. Macroscopically, four developmental stages of ovary and testes were examined which are immature, intermediate mature, mature and spent. The body surface of female fish was rounded, swollen abdomen and reddish pelvic fin during the breading season while the male fish was generally smaller than the female fish, narrower and had reddish pelvic fin. The pectoral fin of male was rough during the breeding season. The matured female gonad was bi-lobed, yellowish in color, larger in size than the testes. The matured male gonad was paired and creamy whitish in color and more or less elongated than the female during the breeding season. The GSI value of female A. testudineus gradually increased from January to June and reached a maximum value in July (12.71±0.73) and the lowest GSI value was recorded in October (1.13±0.10) for female. The highest HSI value of female was observed in January 4.37±0.64 and lowest was observed in July (1.58±0.19). The GSI and HSI were inversely related with each other i. e. when GSI value was highest, at the same time, the HSI value was lowest. The fecundity was counted from the month of April to July by using gravimetric method. The absolute fecundity during April was (16832.80± 673.34) and during July was recorded about (46186.14± 2219.15). The relationship between gonad weight and fecundity, body weight and fecundity was strong positive relation where regression co-efficient was 0.9603 and 0.9265 respectively which indicate that with the increase of body weight and gonad weight, fecundity is also increased. Microscopic observation of ovary of female A. testudineus were studied in mature fish during June to July and observed that more than two different developmental stages of oocytes were present in a single matured ovary which indicates that it is a group asynchronous in nature i. e. the fish can spawn for a long duration. Microscopic observation on mature testes was also performed to know the development stages and was found spermatocytes, spermatids and spermatozoa stages during the month of June and July.