Species‐specific foraging behavior and diets of stream salmonids: An implication for negative impacts on native charr by nonnative trout in Japanese mountain streams

作者：Miles I. Peterson, Satoshi Kitano, Shoichiro Yamamoto, Tomohiro Kando, Yoshiaki Tsuda · 发表于：Ecological Research · 年份：2023 · DOI：10.1111/1440-1703.12419 · 被引用次数：7 · 研究领域：Fish Ecology and Management Studies、Hydrology and Sediment Transport Processes、Aquatic Invertebrate Ecology and Behavior

Abstract Salmonids have been introduced globally as a food source and recreational fishing target. In Japan, brown trout ( Salmo trutta ) and brook trout ( Salvelinus fontinalis ) were introduced in the 19th century and have since spread. In many headwater streams, native white‐spotted charr ( Salvelinus leucomaenis ) are thought to be experiencing negative impacts from these species. The current study examined foraging behavior, microhabitat use, and diet overlap of these three species in Kamikochi, Nagano Prefecture: one of Japan's premier mountain areas. In Kamikochi, many spring‐fed headwater streams are currently dominated by these invasive salmonids and white‐spotted charr have declined drastically over the last half century. Underwater video analysis revealed that while total foraging rates and foraging modes were similar between the three species, brook trout and white‐spotted charr foraged benthically more frequently than brown trout. Microhabitat water depth and flow velocity were similar between species, and fish size had a positive effect on water depth and flow velocity in all three species. Diet analysis indicated that brook trout and white‐spotted charr diets were nearly identical, comprised primary of aquatic invertebrates, while brown trout preyed on a mix of terrestrial and aquatic invertebrates, as well as amphibians and fish. These results indicate that in Kamikochi, the decline of white‐spotted charr is likely most influenced by direct competition with br...