AB 10:227-239 (2010)  -  DOI: https://doi.org/10.3354/ab00280

Habitat use by the Formosan landlocked salmon Oncorhynchus masou formosanus

Chorng-Bin Hsu1, Chyng-Shyan Tzeng2, Chao-Hsien Yeh3, Wen-Hui Kuan4, Mei-Hwa Kuo5, Hsing-Juh Lin1,6,*

1Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
2Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
3Department of Water Resources Engineering and Conservation, Feng Chia University, Taichung 407, Taiwan
4Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, Taipei 243, Taiwan
5Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan
6Biodiversity Research Center, Academia Sinica, Taipei 115, Taiwan
*Corresponding author. Email:

ABSTRACT: The critically endangered Formosan landlocked salmon Oncorhynchus masou formosanus is one of the southernmost natural salmon populations in the world, which only occurs in Chichiawan Stream and its tributaries in the Wuling basin of subtropical Taiwan. We examined habitat uses by different size classes of the Formosan salmon and the sympatric shovelmouth minnow Varicorhinus barbatulus, and identified the relative importance of environmental variables, biotic components and seasonal effects in explaining the variance in the relative occurrences of fish at the catchment scale. After removing seasonal effects, 74.9% of the variation in the relative occurrence of fish was explained by the measured environmental variables and biotic components. Habitat uses by the Formosan salmon and shovelmouth minnow were distinct. The shovelmouth minnow occurred more frequently at sites with a high concentration of NH3-N and high proportions of gravel and riffles, while the Formosan salmon utilized sites at high elevations. Habitat uses by Formosan salmon of different size classes varied slightly. Juvenile and subadult salmon inhabited sites with lower temperatures and current velocities, but adult salmon occurred more frequently with large-grain-sized substratum. Our study showed that variations in the relative occurrence of fish in the Wuling basin were best explained by physicochemical parameters (38.8%), followed by substratum composition (11.4%). The variations exclusively explained by mesohabitat composition, seasonal effects, and biotic components were not significant. This conclusion has important consequences for local managers and conservationists.


KEY WORDS: Physicochemical parameter · Substratum · Habitat composition · Biotic component · Chichiawan Stream · Taiwan


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Cite this article as: Hsu CB, Tzeng CS, Yeh CH, Kuan WH, Kuo MH, Lin HJ (2010) Habitat use by the Formosan landlocked salmon Oncorhynchus masou formosanus. Aquat Biol 10:227-239. https://doi.org/10.3354/ab00280

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