不同饵料及养殖环境对大黄鱼(Larimichthys crocea)形态差异的影响

The Effects of Different Diets and Culture Environments on the Morphological Variations in the Large Yellow Croaker (Larimichthys crocea)

关键词:  大黄鱼  形态  饵料  环境  多元分析

Key words:  Large yellow croaker Larimichthys crocea  Morphology  Diet  Environment, Multivariate analysis

摘要:

本研究通过采集不同环境和不同饲料养殖的岱衢洋大黄鱼(Larimichthys crocea)形态数据，利用聚类分析、主成分分析以及判别分析对3组大黄鱼形态差异进行分析。结果显示，不同环境对大黄鱼体高、尾长存在显著影响，而不同饲料对大黄鱼体高、尾高、尾长、体厚存在显著影响，同时对D3–4、D3–6、D4–6、D5–6框架形态存在显著影响，差异主要集中于躯干前部。表明不同环境下大黄鱼形态变化可能与流速适应相关，而饵料对体型的影响可能是因为营养组成及物质积累的不同。聚类分析显示，配合饲料组与深水网箱组形态更接近，而与冰鲜饲料相距较远。通过主成分分析提取3个主成分，其中配合饲料组与深水网箱组在主成分1上相近，但在主成分3上存在差异，而冰鲜饲料组在各主成分上均离散，表明小网箱冰鲜饲料养殖大黄鱼形态分离较大，体型一致性低。利用判别分析，构建3种条件下大黄鱼体型判别函数，经交互验证，判别函数与预期无显著差异，可用于不同养殖模式大黄鱼的形态判别。本研究初步表明，通过改变养殖环境水流、养殖空间大小、饲料可在一定程度实现养殖大黄鱼形态改良。

Abstract:

The morphological character is an important external indicator of the value of a large yellow croaker (Larimichthys crocea). Therefore, it has become a hotspot how to improve the morphology of the cultured large yellow croaker in the fishery industry. In this paper, we analyzed the morphological differences among the large yellow croakers cultivated in different environments and fed with different diets. We collected the morphological data of three groups of large yellow croakers, and then applied methods such as cluster analysis, principal component analysis and discriminant analysis to analyze the data. The results showed that there were significant differences in the body height, the caudal peduncle length, the caudal peduncle width and the trunk width between the groups. The environment and the diets also had effects on the frame morphology of D3–4, D3–6, D4–6 and D5–6. The morphological differences primarily existed in anterior trunk of the fish, which indicated that the morphological changes caused by the environment might be associated with the flow velocity. We also speculated that the diet might affect the fish morphology due to different nutrition compositions and accumulation. The cluster analysis showed that the formula diet group and the net-cage group clustered closer than the fresh diet group. Three principal components were extracted by principal component analysis, and it showed that the formula diet group and the net-cage group shared similarity in principal component 1, but were different in principal component 3. The fresh diet group was discrete on each principal component. This finding suggested that the large yellow croaker cultured in the small net cage and fed with fresh diet were more diverse in morphology. We also applied discriminant analysis and established the discriminant functions of the large yellow croaker under different conditions. The cross validation analysis showed that there was no significant difference between the discriminant functions and the expectation, which indicated that the discriminant functions could be used in the morphological identification of the large yellow croaker cultured in different patterns. Our study suggested that the morphological improvement of the large yellow croaker would be achieved to some extent by altering the flow velocity, the size of the cultural space and diets.