Abstract

We studied the effect of increasing salinity with respect to growth performance and water quality of Hybrid Red Tilapia (Oreochromis mossambicus × O. niloticus) (1.29 ± 0.48 g and 4.05 ± 0.48 cm) for 77 days, and we compared the obtained results to freshwater rearing. The results indicate no significant difference in all physico-chemical parameters between both variants, which are within the accepted range for fish growth. Better growth performance regarding weight was observed in freshwater rearing. However, in terms of length, the increasing salinity rearing showed the best growth performance. The survival rate decreased with a salinity increase, unlike freshwater rearing which showed 100%. Hybrid Red Tilapia raised in freshwater revealed isometric growth. However, Hybrid Red Tilapia reared in increasing salinity reported negative allometric growth. A strong positive correlation was observed between salinity and total length and weight, and between total length and total weight, while survival was strongly negatively correlated with salinity and total weight. Positive loadings of salinity, \({\text{NH}}_{4}^{ + },\) total length, and total weight were observed relatively to the factor 1, whereas \({\text{NO}}_{2}^{ - }\) and survival show negative loadings. For the factor 2, the chemical variables ( \({\text{NO}}_{2}^{ - },\) \({\text{PO}}_{4}^{{3 - }}\) and \({\text{NH}}_{4}^{ + }\) ) were the important variables. Our experiment suggests that Hybrid Red Tilapia can be reared in biotopes that are subject to climate change or that experience a hot and dry climate.

中文翻译：

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盐度逐渐增加对杂交红罗非鱼（Oreochromis mossambicus × O. niloticus）水质、生存和生长性能的影响

摘要

我们研究了增加盐度对杂交红罗非鱼 (Oreochromis mossambicus × 生长性能和水质的影响O. niloticus)（1.29 ± 0.48 g 和 4.05 ± 0.48 cm）77 天，并将获得的结果与淡水饲养进行比较。结果表明，两种变体之间的所有物理化学参数没有显着差异，在鱼类生长可接受的范围内。在淡水饲养中观察到更好的体重生长性能。但就长度而言，增加盐度饲养表现出最好的生长性能。与淡水养殖的成活率100%不同，成活率随着盐度的增加而下降。在淡水中饲养的杂交红罗非鱼显示出等长生长。然而，在盐度增加的情况下饲养的杂交红罗非鱼报告了负异速生长。盐度与总长度和重量之间以及总长度和总重量之间观察到强正相关，而存活率与盐度和总重量之间呈强负相关。盐度正载荷、\({\text{NH}}_{4}^{ + },\)总长度和总重量分别为相对于因子 1 观察到，而 \({\text{NO}}_{2}^{ - }\) 和生存显示负载荷。对于因子 2，化学变量 (\({\text{NO}}_{2}^{ - },\)\({ \text{PO}}_{4}^{{3 - }}\) 和 \({\text{NH}}_{4 }^{ + }\)) 是重要的变量。我们的实验表明，杂交红罗非鱼可以在易受气候变化或经历炎热干燥气候的生境中饲养。