Ichthyofauna of the Kubo, Tochikura, and Ichinono river systems (Kitakami River drainage, northern Japan), with a comparison of predicted and surveyed species richness.

Yusuke Miyazaki,Masanori Nakae,Hiroshi Senou

doi:10.3897/bdj.2.e1093

Abstract

The potential fish species pool of the Kubo, Tochikura, and Ichinono river systems (tributaries of the Iwai River, Kitakami River drainage), Iwate Prefecture, northern Japan, was compared with the observed ichthyofauna by using historical records and new field surveys. Based on the literature survey, the potential species pool comprised 24 species/subspecies but only 20, including 7 non-native taxa, were recorded during the fieldwork. The absence during the survey of 11 species/subspecies from the potential species pool suggested either that sampling effort was insufficient, or that accurate determination of the potential species pool was hindered by lack of biogeographic data and ecological data related to the habitat use of the species. With respect to freshwater fish conservation in the area, Lethenteron reissneri, Carassius auratus buergeri, Pseudorasbora pumila, Tachysurus tokiensis, Oryzias latipes, and Cottus nozawae are regarded as priority species, and Cyprinus rubrofuscus, Pseudorasbora parva, and Micropterus salmoides as targets for removal.

Highlights

Biodiversity is rapidly declining at a global level due to a variety of anthropogenic pressures (Myers et al 2000, Roberts et al 2002, Brooks et al 2006)
Twenty freshwater fish species/subspecies belonging to 9 families in 6 orders were recorded during field surveys (Figs 3, 4, 5, 6, 7; Table 1); 12 species/subspecies belong to Cypriniformes (62% of the total), 3 to Perciformes (14%), 2 to Salmoniformes (10%), and 1 each to Petromyzontiformes, Siluriformes, and Beloniformes (5% each)
13 of the 24 species/subspecies from our estimated potential species pool were collected during field surveys, including nine national/prefectural red list species (Table 1)

Summary

Introduction

Biodiversity is rapidly declining at a global level due to a variety of anthropogenic pressures (Myers et al 2000, Roberts et al 2002, Brooks et al 2006). When detailed survey data are lacking, determining a region’s potential species pool (Lessard et al 2012) can provide an estimate of local biodiversity status by application of the ecological filter concept (Fattorini and Halle 2004, Hobbs and Norton 2004, Funk et al 2008) Based on this concept, species diversity at the local scale is presumed to be constrained by the regional species pool, and filtered by stochastic and deterministic processes including both nonanthropogenic and/or anthropogenic factors. The nature restoration committee of the Kubo-gawa Ihatov area represents one of the projects based on the Law for the Promotion of Nature Restoration, but is unique in being overseen by private sector administration (Chisaka 2010) Part of this project has focused on the conservation and restoration of the freshwater fishes of the region, which includes most of the Kubo, Tochikura and Ichinono river systems. Ichthyofauna of the Kubo, Tochikura, and Ichinono river systems

Materials and methods

Findings

Discussion