Study on embryonic and larval developmental stages of Sucker head Garra gotyla (Gray 1830; Teleostei; Cyprinidae).

Summary: Garra gotyla is an indigenous coldwater fish of the cyprinid family and has wide geographical distribution in India as well as in other countries of Asia and Africa. Induced breeding in G. gotyla was carried out successfully for the first time and an attempt has been made to document developmental stages chronologically from the first minute of fertilization, through all stages of embryonic development until the fifth day post hatching. This experiment was carried out at 22–24°C water temperature at the Directorate of Coldwater Fisheries Research, Bhimtal, India. During the breeding trial, the fertilization rate was observed as 70–75% and hatching rate was 85–90%. The mature fertilized ova were measured as 0.8–1.0 mm in diameter and the perivitelline membrane became thick soon after fertilization and formation of the germ pole. The periods taken for complete developmental stages were recorded; cleavage stage 111 min (min post fertilization (pf)), blastulation stage 580 min (pf), neurulation and segmentation 1250 min (pf) and hatching was completed after 1420 min. The sac fry was measured as 3 mm in length and took almost 3 days for complete absorption of the yolk content. The major structural and differential changes observed are in head, tail, fins, alimentary canal, rudiments of each organ and appearance of melanophore pigmentation in the whole body. The 5-day-old larvae were measured as 6 mm in length with almost every organ fully differentiated. The present study will be utilized for large-scale production of fingerlings for stock enhancement in rivers, lakes and possibilities of genetic improvement and manipulation at the embryonic stage. [ABSTRACT FROM AUTHOR]