南极鱼类年龄与生长研究进展

Age and growth of Antarctic fish species: a review

南极鱼类生长相对缓慢,独特的生物学特性使其年龄鉴定较其他海区鱼类更为困难。但考虑到鱼类年龄鉴定是开展渔业资源评估的基础,因此过去一些年来,硬质部位,如鳞片、鳍条(棘)、脊椎骨以及耳石等仍成为南极鱼类的主要鉴龄材料。本文对南极鱼类年龄鉴定的方法和材料进行了总结回顾,将年龄鉴定的方法和材料进行比较,分析各自优缺点。结果显示:(1)对于具鳞的南极鱼类,因鳞片在鱼类生长过程中存在重吸收现象,因而利用鳞片及鳍条(棘)单独鉴龄所得出的结果通常小于耳石的鉴龄结果,缺乏精确性;(2)南极鱼类生活跨度较大,高龄鱼体长频次分布严重重叠,以致无法准确判断其年龄结构;(3)耳石重量法易受到特殊个体影响而误判年龄;(4)因鳍条易损坏,脊椎骨采集较为困难,且许多南极鱼类无鳞,目前大多数南极鱼类使用耳石鉴定年龄,其也成为目前最为精准的南极鱼类鉴龄方法,但同时利用鳞片和耳石重量等对鉴定结果进行验证;(5)南极鱼类尚存在无统一的鉴龄标准、人为主观性较强以及缺乏早期生活史研究等不足之处;(6)为了研究南极鱼类早期生活史,耳石微化学及微结构等方法将被广泛利用。

Antarctic fish species have a very long life history and are slow-growing. Age determination of Antarctic fish is more difficult than fish species outside the Antarctic area because of unique biological characteristics. However, age determination of Antarctic fish is the basis of fishery stock assessment. Recently,some calcified structures, such as scales, fin rays, vertebrae and otoliths became the main materials for age determination of Antarctic fish. This review compares different methods and materials of Antarctic fish age determination, as well as analyzes their merits and deficiencies to provide the references for further studying Antarctic fish species. The results showed that, compared to otolith, scales and fin rays were seldom used to age determination of Antarctic fish. Length frequency distribution could not be suitable to age older Antarctic fishes because of the long life history. Otolith weight could erroneously estimate the age of Antarctic fishes because of typical individuals occurring. Because fin rays are easily damaged, vertebrae are difficult to collect, the age of some Antarctic fish species without scales were frequently estimated based on otolith sections and verified by scales as well. Meanwhile, some disadvantages, such as no unified age determination protocol, strong subjectivity and lack of background knowledge of early life history, etc. limit the accuracy and precision of ageing Antarctic fish species. Otolith microchemistry and microstructure will be used extensively for studying early life history of Antarctic fish.