How do dams affect freshwater fish distributions in Japan? Statistical analysis of native and nonnative species with various life histories

Abstract

We examined the effects of dams on freshwater fish species based on data collected during 1990-2004 from 200 drainage systems in Japan. Of the 76 fish species examined, the occurrence of 20 species within Petromyzontidae, Cyprinidae, Cobitididae, Salmonidae, Cottidae, and Gobiidae was negatively affected by the presence of dams located in the downstream reaches of fish survey sites, whereas the occurrence of 12 species within Cyprinidae, Adrianichthyidae, Centrarchidae, and Gobiidae was positively associated with the presence of dams. A significantly higher proportion of the fishes with a negative damming effect were diadromous species as compared to the fishes with a positive damming effect. Conversely, the latter group had a significantly higher proportion of nonnative species than the former. A significant interaction existed between the effects of damming and the effects of elevation on family-specific species richness. Families dominated by native migratory species showed a greater reduction in the number of species above dams at lower elevations, whereas families represented primarily by nonnative species had higher species richness above dams at higher elevations, except for Centrarchidae, which was always higher in species richness above dams regardless of elevation. Based on our findings, dams in Japan have adversely affected native freshwater fishes by blocking their migration routes, favoring nonnative fishes, or altering existing habitats.

The effects of the Three Gorges Dam’s (TGD’s) experimental impoundment on the phytoplankton community in the Xiangxi River, China

“…Spatial distribution shows some discipline and is closely related to the needs of any living being's growth and survival. Documentation of the impact of dams on freshwater fish distribution in Japan revealed that habitat fragmentation was the main factor that affected species distribution [36]. In this study, impoundment changed the algal spatial distribution regime and altered the status of algal cell gathering in the surface water.…”

Modelling basin-scale distribution of fish occurrence probability for assessment of flow and habitat conditions in rivers

“…there was no river fragmentation or flow regulation, the OP of 28 fish species would increase further compared to the increase in scenario D2, while only two fish species that had higher occurrence probabilities in D2 than D1 would decrease. As mentioned above, river fragmentation limits the migration of diadromous fish and decreases their OP (Fukushima et al 2007, Han et al 2008. Furthermore, the indirect effects of dams, e.g.…”

Spatiotemporal patterns of the fish assemblages downstream of the Gezhouba Dam on the Yangtze River

“…The proportion of Coreius in the catch declined to 54% from ~80% ( Figure 2). Because of the habitat selectivity of different species [44,45], significant changes in species compositions resulted in the spatial variability of fish distribution ( Figure 6). …”