Periodic increments in the jumbo squid (Dosidicus gigas) beak: a potential tool for determining age and investigating regional difference in growth rates

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• 作者：Bi Lin Liu ; Xin Jun Chen ; Yong Chen ; Guan Yu Hu ; Wei Yu ; Jin Tao Wang&#8230
• 关键词：Dosidicus gigas ; Rostrum sagittal section ; Increment width ; Beak ; Age
• 刊名：Hydrobiologia
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：790
• 期：1
• 页码：83-92
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Freshwater & Marine Ecology; Ecology; Zoology;
• 出版者：Springer International Publishing
• ISSN：1573-5117
• 卷排序：790

文摘

Age determination of the jumbo squid (Dosidicus gigas) has been successfully carried out over its geographic range based on the use of the rings present in the statoliths. In this study, we propose an additional method to identify ages of D. gigas off the Ecuadorian and Chilean Exclusive Economic Zones (EEZs) waters by using upper beak rostrum sagittal section (RSS) analysis. Our results show periodic growth increments and occasional checks located in the RSS surface. Growth increments meet at the internal rostral axis in the shape of chevron, and the marks in the hood are more discernable and clearer than in the crest. As has been suggested for octopi, checks are thought to represent temperature oscillation and reproductive events. Growth increments are laid down in the RSS daily, and numbers were similar to the numbers of increments used to determine age in statoliths. There was a significant regional difference in age but not in increment width when mantle length effects were considered, where squid off the warm Ecuadorian EEZ waters had a shorter lifespan and higher somatic growth in mantle length than those in the temperate Chilean EEZ waters.