AGE ESTIMATION FOR JUVENILE NOTOTHENIA-ROSSII FROM POTTER COVE, SOUTH SHETLAND ISLANDS
AGE ESTIMATION FOR JUVENILE NOTOTHENIA-ROSSII FROM POTTER COVE, SOUTH SHETLAND ISLANDS
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DOI：
10.1017/s095410209200021x
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发表时间：
1992-06-01
影响因子：
1.6
通讯作者：
CASAUX, RJ
中科院分区：
文献类型：
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作者：
BARRERAORO, ER;CASAUX, RJ
使用鳞片和整个耳石对 1983 年至 1988 年间在南设得兰群岛乔治王岛波特湾采集的幼年 Notothenia rossii 标本进行年龄估计。两种材料的分析结果显示出 96.7% 的一致性。同样，对所选标本的耳石横截面的检查证实了在所有情况下从第二个完整矢状耳石获得的年龄读数。虽然普遍接受的 7 月 1 日被用作鱼类的出生日期来计算年龄，但数据表明 10 月 1 日更接近生物学出生日期，因为该物种在春季孵化。该鱼的身长年龄范围分别为18-44厘米和3-7岁，与已知的峡湾中该物种幼体标本的身长年龄分布非常吻合。观察到的与反算的第 3 龄组平均长度（分别为 24.6 厘米和 25 厘米）之间的比较表明，我们的样本中不仅代表了较大的鱼，而且还代表了该年龄组的整个尺寸范围。这里提供的年龄平均长度数据与乔治王岛金钟湾鱼类报告的数据相似，但与象岛捕获的鱼类不同。使用整个耳石来估计幼年罗西猪笼草的年龄被证明是一种可靠的方法，精度为一年，但对于成年标本来说，这可能不适合。
Scales and whole otoliths were used for age estimation of juvenile Notothenia rossii specimens collected at Potter Cove, King George Island, South Shetland Islands, between 1983 and 1988. Results from the analysis of both types of material showed 96.7% agreement. Likewise, the examination of otolith cross sections of chosen specimens confirmed in all the cases the age readings obtained from the second whole sagittal otolith. Although the commonly accepted 1 July was used as the birth date of the fish for age calculations, data indicate that 1 October is closer to the biological birth date, since this species hatches in Spring. The length-age range of the fish was 18-44 cm and 3-7 years respectively, which fits well with the known length-age distribution of juvenile specimens of the species in the fjord. A comparison between observed and back-calculated mean length of age group 3 (24.6 and 25 cm respectively) indicated that not only the larger fish but the full size range of this age group was represented in our samples. Mean length data at age presented here are similar to the ones reported for fish from Admiralty Bay, King George Island, but differ from those of fish caught off Elephant Island. The use of whole otoliths for age estimation of juvenile N. rossii proved to be a reliable method with a precision of one year but, this might not be an appropriate technique for adult specimens.