西南大西洋拉式南美南极鱼耳石外型特征

Morphometric features of otolith for rockcod(Patagonotothen ramsayi) in the Southwestern Atlantic Ocean

基于2009年12月至2010年1月西南大西洋阿根廷外公海海域采集的拉式南美南极鱼(Patagonotothen ramsayi)145对耳石样本,对其形态特征进行了分析。结果表明,拉式南美南极鱼耳石长(OL)和宽(OW)分别为4.50—7.99 mm和1.99—3.69 mm之间。耳石外型呈狭长有缺刻,基叶长,翼叶短,具明显的主间沟,后端闭合呈钝圆形,整体结构凸凹不平。左右矢耳石形态无显著性差异。耳石绝对尺寸随体长增加而增加,但相对尺寸减少,耳石的形态结构比例基本不变。耳石长、宽、面积(S)及周长(P)与体重呈对数关系,耳石背长(DL)和基叶长(RL)与体重(W)呈指数关系,耳石背宽(DW)与体重呈乘幂关系,而耳石翼叶长(ARL)与体重则呈线性关系。耳石宽、面积、背长、背宽、周长、翼叶长及基叶长与体长(L)拟合符合对数关系,仅耳石长与体长呈线性关系。本研究可为鱼类耳石形态研究提供参考,并为南美南极鱼渔业生物学研究提供基础资料。

Based on the data of 145 pairs of otolith samples from rockcod （Patagonotothen ramsayi） collected in the high Sea of the southern Atlantic Ocean off Argentina during December 2009 to January 2010, the present study analyzed the otolith morphologic features. The results showed that the sagittal otolith of rockcod ranged from 4.50 to 7.99 mm in length （OL） and 1.99 to 3.69 mm in width （OW） and with the attributes of long strum, short antirostrum and apparent excisura, irregular dorsal and ventral margins, blunt round posterior. The size of statolith increased gradually with the increasing of body length （L）, but the ratio of each morphologic parameter to L slowly decreased, and the proportion of morphological structure almost remained stable. There was no significant difference in otolith morphology between left and right otoliths. The relationships between OL, OW, area （S） and perimeter （P） were best described by logarithmic functions with body with （W）; dorsal length （DL） and rostrum length （RL） were best described by exponential functions with W; the relationships between dorsal width （DW） or antirostrum length （ARL） and W were presented as power or linear functions. The relationships between OW, S, DL, DW, P, RL and ARL were best described by logarithmic functions with body length, while the relatioship between OL and L was best described by linear function. This study can provide the references for fish otolith morphometric analysis and the basic information to the fishery biological study on rockcod.