臺灣鮭魚的再考證－鰭條數目

本文以透明骨酪雙重染色及X光技術，重新檢查現存於臺灣大甲溪上游七家灣棲地，和博物館館藏過去臺灣鮭魚(Oncorhynchus masou formosanus)臀鰭鰭條的數目。同時考証鮭魚和鱒魚之定義與鮭科魚類鰭條的計算方式。日本的研究者應該都採Hikita(1962)的計算方式，將位於臀鰭之全部的鰭條，包括不發達的小鰭條都計算在內(total ray-count)。但是若是採Behnke的prcincipal ray-count計算方式，臺灣鮭魚臀鰭鰭條數目可能為11或12而非13 『If only principal rays are counted, this count (3,10) would probably be 11 or 12 』。此外計算脊椎骨數目，亦可清楚區分臺灣鮭魚與其他三個櫻鮭家族之亞種( Oncorhynchus masou complex: masu (Oncorhynchus masou masou), Amago (O. masou ishikawae), Biwa (Oncorhynchus masou subsp.)。

關鍵字

臺灣；魚類；陸封；鰭；形質

並列摘要

In this study, numbers of anal fin rays in Formosa landlocked salmon, existing population and historical museum samples, were examined by using both X-ray radiography and double stained techniques. Three meristic characters (numbers of vertebrae, dorsal fin rays, and anal fin rays) were compared among three recognized species of cherry salmon complex (On corhynchus masou complex: masu (Oncorhynchus masou masouy, Amago (0. tnasou ishikawae), Biwa (Oncorhynchus masou subsp .) and specimens of Formosa landlocked salmon. A total of 196 specimens were examined. Their vertebral number, dorsal and anal fin rays were counted. Taiwan specimens, referred to as Formosa landlocked salmon, were shown to be a distinct subspecies distinguished from the masu, Amago and Biwa salmon from Japan using meristic counts. If only principal rays are counted as suggested by Behnke, the numbers of anal fin rays in Formosa landlocked salmon would probably be 11 or 12. The X-ray radiography is very useful in determining meristic characters especially fin rays and vertebrae. It is simple, objective, non-invasive, and more precise than the previously used dissection method. In addition, it is fast and inexpensive. Vertebrae counting is also proven to be an unambiguous diagnostic feature for subspecies assignment in Oncorhynchus masou species.

並列關鍵字

Taiwan ； fish ； landlocked ； fin ； character

國際替代計量

臺灣鮭魚的再考證－鰭條數目

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