Value-per-recruit analysis of bighand thornyhead Sebastolobus macrochir caught off the Pacific coast of northern Honshu, Japan

Bio-economic model

The yield-per-recruit (YPR) analysis has been used to assess growth-overfishing of exploited fish stocks. Since the ex-vessel price per weight widely depends on the size of the fish, the result of the YPR does not imply the revenue. The value-per-recruit (VPR) analysis, which is an economic expansion of the YPR analysis, was conducted for bighand thornyhead Sebastolobus macrochir caught off the Pacific coast of northern Honshu, Japan. The results showed that, under the current age at first capture (tc = 3), the current fishing mortality (F = 0.12) was close to optimum level. However, under the current F, optimum tc in the VPR model was 8 years and would lead to a 47% increase compared to the current revenue. The maximum YPR was obtained at tc = 6 years, but the revenue at tc = 6 only gave a 20% increase in the maximum revenue. The difference was caused by the size dependency of the ex-vessel price per weight. The VPR model would generate fisheries management plans with both economical and biological consideration and would help in making general consensus of fisheries management strategies.

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