Nippon Suisan Gakkaishi 72 (5), 850-859 (2006)

Evaluation of VPA estimates of population size of brown sole Pleuronectes herzensteini in northern Hokkaido, Japan

KAZUTAKA SHIMODA,1a* MIZUE MUROOKA,2 KAZUHIKO ITAYA3 AND NOBORU HOSHINO4b

1Hokkaido Wakkanai Fisheries Experimental Station, Wakkanai, Hokkaido 097-0001, 2Hokkaido Abashiri Fisheries Experimental Station, Abashiri, Hokkaido 099-3119, 3Hokkaido Central Fisheries Experimental Station, Yoichi, Hokkaido 046-8555, 4Hokkaido Fish Hatchery, Eniwa, Hokkaido 061-1433, Japan

Evaluation of population size estimates from VPA (back calculation), VPA (forward calculation) and ADAPT VPA of brown sole Pleuronectes herzensteini population in northern Hokkaido, Japan were investigated by retrospective analysis. Relative error between population size by VPA based on eight years of fishing data and estimated population size by three methods of VPA based on one year of fishing data were −54~+109% in VPA (back calculation), −41~+59% in VPA (forward calculation) and −53~+54% in ADAPT VPA. Relative error of age one by VPA (forward calculation) was the lowest of the three methods. At age three to six, relative error by VPA (back calculation) and ADAPT VPA were lower than that of VPA (forward calculation). Relative error of age two and seven showed no different between the methods. We tried to calculate the population size of age one to two by VPA (forward calculation) and over age three by VPA (back calculation). Relative error by the new method was −26~+5%.


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