| 英文摘要 |
This project aims to analyze the otolith of southern bluefin tuna (SBT, Thunnus maccoyii) collected by scientific observers on Taiwanese longline vessels. The age of each SBT sampled for the otolith will be estimated by examining the otolith annuli. These data together with length and weight data will be used to evaluate the growth rate parameters of the SBT caught by Taiwanese longliners. Length and weight data of all SBT caught will be transformed into age data to develop the age composition via the age-length (weight) key. Otolith carbon stable isotope may be influenced by physiology, food and temperature while otolith oxygen isotope is influenced by water temperature. This study will evaluate the physiological and environmental effects on otolith stable isotopic composition of the SBT. The outcome will provide further insight into the autecology of the SBT. |