Hooks equipped with magnets can increase catches of blue shark (Prionace glauca) by longline fishery

Authors: 

Porsmoguer, S.B., Banaru, D., Boudouresque, C.F., Dekeyser, I. and Almarcha, C.

Year: 

2015

Journal/Publisher Name: 

Fisheries Research

Volume (Issue #): 

172

Page #s: 

345-351

Contact information: 

Aix-Marseille University
Summary: 

Pelagic longline hooks equipped with magnets were tested for their ability to repel blue sharks.  Tests were conducted aboard pelagic longliners operating in the Northeast Atlantic Ocean. Two magnets, one large and one small, were tested. Magnets were manually attached to the hooks (polarized so the magnet field was oriented N or S and in parallel with the hook axis). Three test zones, each with 5 hooks with 1 magnet, 11 hooks with 2 magnets and 16 control hooks, were deployed along a longline. The results indicated that blue shark catch rates were not reduced with the use of magnets, and can instead have an increased attractive effect. The attraction was higher with the large magnet.