تعييم زمان تخم ريزي و تغييرات چرخه توليد مثلي هامون ماهي بر مبناي شاخص وزني گناد شاخص وزني كبد و شاخص چاقي

Determination Spawning Season and Changes in Reproduction Cycle of Schizothorax zarudnyi and Condition Factor in Hamoon Lake

Schizothorax zarudnyi is one of the most economic and endemic species, which are found in rivers and triple lagoons of Hamoon. In this study, reproduction cycle, type, season and optimum temperature of spawning period was studied from July 1998 to June 1999. The maximum GSI was 7.9-9.6 in March and April with 14-18°C mean temperatures. The minimum GSI was 0.92 in May. Variation in GSI values shows that reproduction has annual cycle which begins in May and ends in April of the next year. From October significant increase of oocyte diameter and GSI were observed in 2 different groups, while oocyte distribution observed only in one group in May. The rate of HSI had flucatuation, during resting period of ovule (from May to September) and from October simultaneously with significant increase of GSI, the HSI increased and continued to January and decreased in March and April. The condition factor, was changed during reproduction cycle and it was minimum in March (0.92). Concerning these investigation, Sch. zarudnyi is a total spawner and showing a synchronous ovary.