Examination of nutritional effect of tuna longline discards on albatross population

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K12258
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental and ecological symbiosis
• Research Institution: Fisheries Research and Education Agency
• Principal Investigator: INOUE Yukiko 国立研究開発法人水産研究・教育機構, 国際水産資源研究所, 研究員 (40747507)
• Co-Investigator(Kenkyū-buntansha): 南 浩史 国立研究開発法人水産研究・教育機構, 国際水産資源研究所, グループ長 (20371932) ; 新妻 靖章 名城大学, 農学部, 教授 (00387763) ; 石樋 由香 国立研究開発法人水産研究・教育機構, 増養殖研究所, 主任研究員 (10372046)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: bycatch / discard / albatross / seabird / isotope / body condition

Outline of Final Research Achievements

Isotope ratio and body condition of the Laysan albatross coming around a vessel and the foraging of the discards from longline vessels by the Laysan albatross were examined. The body condition was defined as the number of the past days from starting food limitation. By the feeding experiment, the regression formula to estimate the number of the past days after starting the food limitation was obtained using the blood component, which was applied to wild individuals. As a result, the number of the past days after starting the food limitation had large difference among the individuals, and it was indicated that the body condition of the individuals coming around the vessel was various. Individuals with good body condition tended to have high nitrogen isotope ratio of a plasma. Because there is no significant difference between the nitrogen isotope ratio of the discards and squids, it could not be examined the foraging of the discards by the albatrosses coming around the vessels.

Free Research Field

ecology, physiology