Numerical and Economic Contributions of Wild and Hatchery Pink Salmon to Commercial Catches in Japan Estimated from Mass Otolith Markings

Abstract

Evaluating the contribution of wild and hatchery fish to a fishery is essential to understand economic feasibility as well as the impact of hatchery fish on the ecosystem. However, a precise estimate of this contribution is often difficult to obtain, particularly when hatchery and wild fish are mixed in the catch. In this study, we quantified the contribution of hatchery and wild Pink Salmon Oncorhynchus gorbuscha to the mixed-stock commercial fishery in Japan by identifying the ratio of otolith-marked hatchery fish to unmarked and presumably wild fish. The contribution of hatchery fish to the total coastal catch of Pink Salmon in Japan was estimated to be 16.6% and 26.4% in 2011 and 2012, respectively. Thus, the majority of the commercial salmon catch originated from naturally spawned wild fish. Economic yield per release by Japanese hatcheries was 2.2 yen (<2.2) (US$0.022) and <1.5 in 2011 and 2012.

Numbers and Biomass of Natural‐ and Hatchery‐Origin Pink Salmon, Chum Salmon, and Sockeye Salmon in the North Pacific Ocean, 1925–2015

“…() and Ohnuki et al. (), recognizing high uncertainty in the estimates of natural‐origin Pink Salmon. Recent evidence indicates that Japan produces some natural‐origin Chum Salmon (Miyakoshi et al.…”

Lessons from Japan marine stock enhancement and sea ranching programmes over 100 years

“…For chum salmon, YPR was recalculated based on newly estimated mean body weights from catch statistics for 1974–2017 obtained from the NPAFC, and return rates for 1974–2017 from the FRA (http://salmon.fra.affrc.go.jp/zousyoku/sakemasu.html). The revised YPR for chum salmon was 86 ± 29 g. For Japanese scallop, mean body weights were recalculated based on the work of Kurata (1999), and the revised estimate was 177 ± 30 g. YPR values were reported for pink salmon in Hokkaido in terms of amount of money (1.5–2.2 yen/released individual), calculated based on the estimated proportion of Hokkaido-origin hatchery fish in the landings (Ohnuki, Morita, Tokuda, Okamoto, & Ohkuma, 2015). Thus, that case did not give the YPR in weight, the recapture rates, n or cost performance of a seed (v/c); therefore, i excluded the case of pink salmon in Hokkaido from the analysis.…”

“…For the calculation of the YPR of chum salmon, mean body weights were revised from 1974–2017 catch statistics obtained from the NPAFC and 1974–2017 return rates in Hokkaido obtained from the FRA (http://salmon.fra.affrc.go.jp/zousyoku/sakemasu.html). The revised mean body weight of chum salmon was 3 197 ± 306 g. Mean body weights were also recalculated for Japanese scallop based on Kurata (1999), yielding a revised estimate of 177 ± 30 g. YPR values reported for pink salmon in Hokkaido by Ohnuki et al (2015) were given in monetary terms (1.5–2.2 yen/released individual), which was calculated from the estimated proportion of Hokkaido-originated hatchery fish in the landings. Because the YPR of pink salmon in Hokkaido was not provided in terms of weight, recapture rate, or cost performance of a seed ( v / c ), I excluded this case from the analysis.…”

Gene expression of neuronal soluble N‐ethylmaleimide‐sensitive factor attachment protein receptor complex components in the olfactory organ and brain during seaward and homeward migration by pink salmon (Oncorhynchus gorbuscha)

“…Pink salmon spawn at a fixed age (2 years old) and various homing rates have been reported among local populations and origins (wild or hatchery) ( e.g ., Bett et al ., 2017; Keefer & Caudill, 2014; Mortensen et al ., 2002; Thedinga et al ., 2000). The south‐east population of pink salmon in the western Pacific Ocean is utilized for stock enhancements in eastern Hokkaido, Japan (Morita et al ., 2006; Ohnuki et al ., 2015; Quinn, 2018). Limited information is currently available on the homing rate of the Japanese population of pink salmon due to hatchery‐released individuals without otolith marks in the last few decades and/or undeveloped genomic information.…”