Ảnh hưởng của độ mặn lên chỉ tiêu sinh sản của cá sặc rằn (Trichogaster pectoralis Regan, 1910) tại Bạc Liêu

Abstract

Researching the effects of different salinity levels on reproductive parameters of Snakeskin gourami fish serves as a basis for the development of freshwater fish farming under the impact of climate change. The experiment was carried out with a completely randomized design model with 5 salinity treatments (0‰, 2‰, 4‰, 6‰ and 8‰) and 3 replicates. The broodstocks have a weight of 109 - 138 g/fish and male: female ratio was 1:1. After acclimation of the salinity level for 4 hours, spawning induction was injected once with hormones LH-RHa 0,1 mg + 5 mg DOM/kg female. Environmental parameters during the experimental period were maintained at temperatures from 27,4 to 28,90C, pH 7,6 - 7,8, NH3 0,06 - 0,11 mg/L, and NO2- 0,02 - 0,06 mg/L. The results showed that the latency period tends to increase with increasing salinity (913 minutes at 0‰ and 1,156 minutes at 8‰); the spawning rate of broodstocks in the treatments was not significantly different (p>0,05) and ranged from 66,7 to 100%. fertilization rate was lowest at 8‰ treatment and there was a significant difference in fertilization rate between 8 ‰ and remaining treatments (p<0.05). The hatching rate was highest at 2‰ treatment (82,33%), and lowest at 8‰ salinity (0,67%) (p<0.05). Survival rate was not significantly different (p>0.05) in the salinities from 0‰ to 6‰ and reaches from 66,67 to 98,33%. It can be concluded that snakeskin gourami can be reproduced at salinity levels from 2 to 6‰, the most optimal is 2‰.