Investigation on propagation of Sparidentex hasta (sobaity) in spawning tanks and rearing of larvae up to Fingerling

Abstract

In order to achieve biotechnic normative of Sobaity Sparidentex hasta propagation and its fries rearing, 96 brood stocks were caught by using hook from Bandar Imam and Mahshahr creeks. For natural spawning, at first stage some selected broodstocks (sex ratio 2:1 & 1:1 male to female) were directly introduced to spawning tanks. In this method eggs were absorbed and spawning was not occured. For artificial spawning (natural spawning with hormone injection): At second stage for males, in one step, 40 g kg-1 and 200 Iu kg-1 body weight and for females, in two steps, 75 g kg-1 and 500 Iu kg-1 LRHa & HCG hormones were injected. After introducing broodstocks to 40- tone oval tanks, spawning occurred only in female and also some ingected broodstocks were spawned artificially and all obtained larvae died after four days. At third stage 6 g kg-1 and 1000 Iu kg-1 body weight of PG and HCG hormones were injected to broodstock respectively. HCG hormone injected in two steps (1/2 dose each stop in 24 hours duration). Metoclopramide was used at the first step and PG hormone injected with second step of HCG coincidentally. In this method spawning, fertilization and fry production occurred. The results indicated that sobaity, with hormone injection is able to spawn at 12-19 c (which is available in Khouzestan in March). The time of hatching was 42-50 hours, absorption of larvae Yolk sac 96-120 hours. The size of one- day- larvae was 1.4- 1.7mm and 65-day- fry was 24mm.