Estimating the spawning escapement of pink salmon Oncorhynchus gorbuscha using the area-under-the-curve method in the Rusha River of the Shiretoko Peninsula, Hokkaido Island

Abstract

Pacific salmon Oncorhynchus spp. plays a role in sustaining the biodiversity and production of the terrestrial ecosystem. Accurate estimation of the escapement and spawning dynamics is important for the quantifying the effect of salmon on the riparian ecosystem. The objective of this paper is to estimate accurately the escapement and spawning dynamics of wild pink salmon O. gorbuscha at the Rusha River in the Shiretoko World Natural Heritage area in 2006-2008. The escapement of pink salmon was estimated by the area-under-the-curve method (AUC) with the standard error based on the bootstrap method. The estimated escapement indicated appropriate results. The carrying capacity of spawning redds, however, was far lower than escapements in the available spawning area.