Morphology And Growth Characteristics On Beak Of Loliginidae Lesueur In The East China Sea

As an stable sclerous tissues in cephalopods, beak has a large number of biological information and high scientific research value. As Cephalopod species is numerous and multifarious in the East China sea, the research of beak shape has broad application prospect. This study explored the basic characteristics like morphology properties and growth characteristics of beak, as well as the relationships between the individual growth index and morphological parameters of beak. Picking out stable indexs which were not affected by growth. Then, we could distinguish different loligo with this stable indexs. Based on this stable indexs, we also could build a classification system about squid belong to Loliginidae Lesueur that live in the East China Sea.Data processing methods include the following points. According to the measured beak morphological parameters, describing the correlation of the growth on the structure. After this, principal components analysis need to be done on morphological parameters of the upper beak and lower beak. We can sort out the representative of the upper beak and lower beak based on the results of principal components analysis. Describe the relationship between the morphological parameters of loligo beak and mantle length, as well as body weight, by making use of linear regression and power function. According to the samples of loligo collected by bottom trawl from 2011 to 2015 in the East China sea,we analyzed the characteristics of the beak morphological parameters. Based on the results of principal components analysis, we can sort out UHL,UCL,LHL and LLWL as the representative of Uroteuthis edulis; ULWL,LCL and LLWLas the representative of Uroteuthis duvauceli; UHL,UCL,ULWL,LCL and LLWL as the representative of Loliolus beka; UCL,ULWL,LCL and LLWLas the representative of Loliolus japonica; UHL,LLWL and LWLas the representative of Loligo kobiensis; UHL,UCL,LCL and LLWL as the representative of Loliolus uyii; ULWL,LLWL and LWWas the representative of Sepioteuthis lessoniana. Described the relationship between beak morphological parameters with mantle length and body weight.On the basis of relation between beak morphological parameters ratios with mantle length and body weight, stable indexs which were not affected by growth were picked out. Results indicate that beak morphological parameters increased with the ontogenic growth of squid. There were eight same stable indexs between seven species belong to Loliginidae Lesueur that live in the East China Sea. Results of one-way ANOVA(P<0.05)showed that there was no significant difference between Uroteuthis, Loliolus and Sepioteuthis in URL/UHL,URL/UCL and URL/ULWL. Also, there was no significant difference between Uroteuthis edulis and Uroteuthis duvauceli in URL/ULWL,UHL/UCL,UHL/ULWL,UCL/ULWL and LHL/LCL.