Study on the methods to mitigate the bycatch of juvenile bigeye tuna by introducing Double-FADs with light stimulus for tuna purse seine fishery in the Western and Central Pacific Ocean

Authors: 

Kawamoto, T., Yoshimoto, S., Asakawa, E., Sato, K., Okamoto, H., Kumazawa, T., Oshima, T., Takao, Y. and Hasegawa, S.

Year: 

2012

Journal/Publisher Name: 

Western and Central Pacific Fisheries Commission

Volume (Issue #): 

WCPFC-SC8-2012/EB-WP-17

Page #s: 

14

Contact information: 

Kyokuyo Suisan Co., Ltd.
Summary: 

A Double-FAD design was tested for it's ability to mitigate the incidental capture of bigeye tuna in purse fisheries of the Western and Central Pacific Ocean.  The design consisted of two separate FADs with underwater light stimuli attached.  The number of animals caught was not large enough to conduct statistical analyses, but based on the weight of fish, the size proportion of skipjack, yellowfin and bigeye was bigger using the Double-FAD design comapared to the normal design.  The bycatch rate (proportion of total catch) of bigeye tuna was 6.1% and 7.2% on Double-FADs and 8.9% and 14.2% on normal FADs for numbers and weight respectively.  The proportion of skipjack tuna caught on the Double-FADs was 58.6% (number) and 29.1% (weight) compared to 72.4% (number) and 39% (weight) with the normal FAD.  The proportion of yellowfin tuna on the Double-FADs was 35.4% (number) and 63.7% (weight), while on normal FADs the proportion was 18.7% (number) and 46.8% (weight).  It appears this design has some effect on reducing bigeye tuna bycatch, despite the low sample size.