| 英文摘要 |
There were 38 whale sharks barged into set nets in 2014, 19 of them were tagged and released, and 3 others were also observed. In 41 individuals, there were 5 (12.2%) from Yilan, 10 (24.4%) from Hualien, 18 (43.9%) from Taitung, 1 (2.4%) from Pingtung, 4 (9.8%) from Penghu, and 3 (7.3%) from Hsinchu and Miaoli; there were 33 (80.5%) from the east, and 8 (19.5%) from the west, converted to catch per unit effort as being calculated to be 0.78 individual per set net per year in the east and 0.76 individual per set net per year, respectively. The amount of male whale sharks was significant bigger than which of female in sex structure analysis. Both the mean total length (TL) and median TL in 2014 were smaller than which in 2013, and most whale sharks which occurred in Taiwan waters were 3-9 years old immature individuals based on age structure analysis. Two SPOTs were tagged on a 6.7 m TL immature female caught in Penghu on Oct. 30 2013 and the other 5.1 m TL female also caught in Penghu on Nov. 27 2013. Their position signals were still received during 2014. The first one swam southward to the western waters off Philippines after release and remained there for many days, then moved west through the South China Sea to the Gulf of Thailand. This individual usually moved to higher temperature as near surface regions in dusk time, and sometimes moved to lower temperature (7～10 °C) regions based on time at temperature data. The second one also swam west to the South China Sea then entered into the Gulf of Thailand at last. This shark stayed in 23-＞30 °C waters averagely, and dived to 10-15 °C regions in few times. A 6.1 m TL male tagged and released off Hsinchu on 49 April 2014 moved north to the East China Sea, and remained in continental shelf regions until 27 Oct. when we received its last signal in Tanega Shima waters, Japan. This male shark stayed mainly in the waters where the temperatures were 27-30 °C, and sometimes migrated to lower temperature (10-15 °C) waters. Another 7.5 m TL female released in Penghu waters on 31 Oct. swam fast south to southwest waters 80-100 km far from Pingtung and stayed in that region until 14 Nov. This individual occupied mainly in 27-30 °C waters and occurred in lower temperature (0-3 °C) waters in few times. Total of 4 great white sharks were caught between 2013 and 2014. Since the megamouth shark was found and named, there were 87 individual records until now, and 43 of them were from Taiwan as top one region of the world, even 32 were reported in 2013-2014. All megamouth sharks were caught by drift gill nets in Hualien and the locations were gathered in coastal and inshore waters. There were more females as 20 individuals (62.5%) with 250-710 cm TLs, 11 males with 363-484 cm TLs were caught in Hualien waters with sex ratio (male/total) of 0.35. Muscle tissue samples from 4 whale sharks and 5 megamouth sharks were used for nitrogen and carbon stable isotope analysis. We found that although both whale and megamouth sharks were filter-feeding shark species, they fed very different types of prey and also occupied in dissimilar environmental waters. More samples are needed to be analyzed further in the future. According to results above, if the megamouth shark will be manage or protected in the future, the strategy should be different from the whale shark.There were 38 whale sharks barged into set nets in 2014, 19 of them were tagged and released, and 3 others were also observed. In 41 individuals, there were 5 (12.2%) from Yilan, 10 (24.4%) from Hualien, 18 (43.9%) from Taitung, 1 (2.4%) from Pingtung, 4 (9.8%) from Penghu, and 3 (7.3%) from Hsinchu and Miaoli; there were 33 (80.5%) from the east, and 8 (19.5%) from the west, converted to catch per unit effort as being calculated to be 0.59 individual per set net per year in the east and 0.57 individual per set net per year, respectively. The amount of male whale sharks was significant bigger than which of female in sex structure analysis. Both the mean total length (TL) and median TL in 2014 were smaller than which in 2013, and most whale sharks which occurred in Taiwan waters were 3-9 years old immature individuals based on age structure analysis. Two SPOTs were tagged on a 6.7 m TL immature female caught in Penghu on Oct. 30 2013 and the other 5.1 m TL female also caught in Penghu on Nov. 27 2013. Their position signals were still received during 2014. The first one swam southward to the western waters off Philippines after release and remained there for many days, then moved west through the South China Sea to the Gulf of Thailand. This individual usually moved to higher temperature as near surface regions in dusk time, and sometimes moved to lower temperature (7～10 °C) regions based on time at temperature data. The second one also swam west to the South China Sea then entered into the Gulf of Thailand at last. This shark stayed in 23-＞30 °C waters averagely, and dived to 10-15 °C regions in few times. A 6.1 m TL male tagged and released off Hsinchu on 49 April 2014 moved north to the East China Sea, and remained in continental shelf regions until 27 Oct. when we received its last signal in Tanega Shima waters, Japan. This male shark stayed mainly in the waters where the temperatures were 27-30 °C, and sometimes migrated to lower temperature (10-15 °C) waters. Another 7.5 m TL female released in Penghu waters on 31 Oct. swam fast south to southwest waters 80-100 km There were 38 whale sharks barged into set nets in 2014, 19 of them were tagged and released, and 3 others were also observed. In 41 individuals, there were 5 (12.2%) from Yilan, 10 (24.4%) from Hualien, 18 (43.9%) from Taitung, 1 (2.4%) from Pingtung, 4 (9.8%) from Penghu, and 3 (7.3%) from Hsinchu and Miaoli; there were 33 (80.5%) from the east, and 8 (19.5%) from the west, converted to catch per unit effort as being calculated to be 0.78 individual per set net per year in the east and 0.76 individual per set net per year, respectively. The amount of male whale sharks was significant bigger than which of female in sex structure analysis. Both the mean total length (TL) and median TL in 2014 were smaller than which in 2013, and most whale sharks which occurred in Taiwan waters were 3-9 years old immature individuals based on age structure analysis. Two SPOTs were tagged on a 6.7 m TL immature female caught in Penghu on Oct. 30 2013 and the other 5.1 m TL female also caught in Penghu on Nov. 27 2013. Their position signals were still received during 2014. The first one swam southward to the western waters off Philippines after release and remained there for many days, then moved west through the South China Sea to the Gulf of Thailand. This individual usually moved to higher temperature as near surface regions in dusk time, and sometimes moved to lower temperature (7～10 °C) regions based on time at temperature data. The second one also swam west to the South China Sea then entered into the Gulf of Thailand at last. This shark stayed in 23-＞30 °C waters averagely, and dived to 10-15 °C regions in few times. A 6.1 m TL male tagged and released off Hsinchu on 49 April 2014 moved north to the East China Sea, and remained in continental shelf regions until 27 Oct. when we received its last signal in Tanega Shima waters, Japan. This male shark stayed mainly in the waters where the temperatures were 27-30 °C, and sometimes migrated to lower temperature (10-15 °C) waters. Another 7.5 m TL female released in Penghu waters on 31 Oct. swam fast south to southwest waters 80-100 km far from Pingtung and stayed in that region until 14 Nov. This individual occupied mainly in 27-30 °C waters and occurred in lower temperature (0-3 °C) waters in few times. Total of 4 great white sharks were caught between 2013 and 2014. Since the megamouth shark was found and named, there were 87 individual records until now, and 43 of them were from Taiwan as top one region of the world, even 32 were reported in 2013-2014. All megamouth sharks were caught by drift gill nets in Hualien and the locations were gathered in coastal and inshore waters. There were more females as 20 individuals (62.5%) with 250-710 cm TLs, 11 males with 363-484 cm TLs were caught in Hualien waters with sex ratio (male/total) of 0.35. Muscle tissue samples from 4 whale sharks and 5 megamouth sharks were used for nitrogen and carbon stable isotope analysis. We found that although both whale and megamouth sharks were filter-feeding shark species, they fed very different types of prey and also occupied in dissimilar environmental waters. More samples are needed to be analyzed further in the future. According to results above, if the megamouth shark will be manage or protected in the future, the strategy should be different from the whale shark.far from Pingtung and stayed in that region until 14 Nov. This individual occupied mainly in 27-30 °C waters and occurred in lower temperature (0-3 °C) waters in few times. Total of 4 great white sharks were caught between 2013 and 2014. Since the megamouth shark was found and named, there were 87 individual records until now, and 43 of them were from Taiwan as top one region of the world, even 32 were reported in 2013-2014. All megamouth sharks were caught by drift gill nets in Hualien and the locations were gathered in coastal and inshore waters. There were more females as 20 individuals (62.5%) with 250-710 cm TLs, 11 males with 363-484 cm TLs were caught in Hualien waters with sex ratio (male/total) of 0.35. Muscle tissue samples from 4 whale sharks and 5 megamouth sharks were used for nitrogen and carbon stable isotope analysis. We found that although both whale and megamouth sharks were filter-feeding shark species, they fed very different types of prey and also occupied in dissimilar environmental waters. More samples are needed to be analyzed further in the future. According to results above, if the megamouth shark will be manage or protected in the future, the strategy should be different from the whale shark. |
