In the 1970s, about 50 Kuril harbor seals (Phoca vitulina stejnegeri) were observed hauling out in Cape Erimo, Hokkaido, Japan. However, the number increased to approximately 600 individuals in the 2000s, which was 12 times the number recorded previously. Consequently, damage to the fish catch in the salmon fixed nets also increased and has become a serious problem. However, very few quantitative assessment reports have been published about the 70 incidents of damage to fish catches.
In this study, we tracked the seals using acoustic telemetry in order to understand their behavior around the nets, and we also carried out a questionnaire survey to ascertain the number of salmon that were damaged by seals and the behavior of the 75 incidental seals caught in the nets between 2012 and 2015.
The results indicated a large number of seals stayed around set net “M,” which is the closest net to the haul-out site (located about 3 km east of the site). They visited the site frequently and for long periods of time. The proportion of salmon bitten by seals was also large in the “M” net, and the percentage has risen every year. Furthermore, the number of seals caught (85) was also high in net “M.”
This study investigated the damage to the salmon fishery fixed equipment caused by Kuril harbor seals in Japan by evaluating seal behavior and by undertaking a questionnaire survey.
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