臺灣櫻花鉤吻鮭起源之機制

The Straying and Migrating Mechanisms of Oncorhynchus masou formosanus

謝英宗(Ying-Tzung Shieh)

《國立臺灣博物館學刊》 62卷2期 (2009/06) Pp. 27-40

摘要

位處亞熱帶的臺灣，理論上應該不會有鮭魚生存才對。研究指出臺灣櫻花鉤吻鮭可能原係太平洋洄游性魚類，估計在臺灣已有約80萬年的生存歷史。前人的研究認為臺灣櫻花鉤吻鮭是在冰河時期，因海水面下降、水溫降低，使得北方櫻花鉤吻鮭族群往南播遷而被陸封於臺灣，但對於臺灣櫻花鉤吻鮭播遷機制的討論則付之闕如，本文的目的在討論臺灣櫻花鉤吻鮭播遷的可能機制，並推測距今約78萬年前(Bruhnes/Matuyama Boundary)前的MIS 20的冰河消退期，由於隕石的撞擊導致氣候快速回冷，使高緯度地區河川再度被冰封，伴隨著地球磁極的轉換和磁場強度減弱的快速變化，則是最有可能是誘使西伯利亞黑龍江的鮭魚往南拓殖到臺灣的機制，而後又因洄游路徑被阻斷被陸封於臺灣河川，進而種化為臺灣櫻花鉤吻鮭孑遺至今。

關鍵字

臺灣櫻花鉤吻鮭魚 ； 陸封機制 ； 古氣候 ； 古地磁

並列摘要

Since the Taiwan Island is located in a subtropical area; theoretically salmon should not exist there. Previous studies indicated Formosa salmon (Oncorhynchus masouformosanus) might be one of the ancient Pacific salmons, migrated to Taiwan mountain streams and became landlocked since 0.8Ma. Many researchers also suggest that the migration of Formosa salmon, from the higher latitude to the lower latitude area, was caused by the low seawater temperature and low sea level during the glacial period. However, all of these previous studies did not answer what might have been the migration mechanism of Formosa salmon. In this paper, the cause of the northern Pacific salmon to migrate, stray, been landlocked and become Formosa salmon was proposed. During the deglaciation of marine oxygen isotope stage 20 or around 0.78 Ma, the meteorite impacted the Earth, caused an abrupt paleomagnetic reverse and the warm climate to cool down dramatically which triggered the migration of Northern Pacific salmon to Taiwan.

並列關鍵字

Formosa salmon ； landlocked mechanism ； paleoclimate ； paleomagnet