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Vol. 37 No. 4, 1998
Microhabitat Use by Formosan Landlocked Salmon, Oncorhynchus masou formosanus
Eric
Hsienshao Tsao1,*, Yao-Sung Lin1, Robert J. Behnke2
and Eric P. Berqerserr2
1Department
of Zoology, National Taiwan University, Taipei, Taiwan 106
2Department of Fishery and Wildlife Biology, Colorado
State University, Fort Collins, CO 80523, USA
Eric
Hsienshao Tsao, Yao-Sung Lin, Robert J. Behnke and Eric P. Bergersen
(1998) Microhabitat requirements of the Formosan landlocked
salmon (Oncorhynchus masou formosanus)
were studied in four 85-m-long sections of the Chichiawan Stream.
Underwater observations to locate the salmon, followed by measurements
of physical habitat variables, were conducted along transects
established at 5-m intervals. Available and occupied habitat units were
compared to quantify water depth, current velocity, instream cover, and
substrate type of suitable microhabitat. Data were pooled to represent
salmon habitat use during 2 water temperature periods. Newly emerged
fry extensively used habitats with nearly no current velocity and
abundant instream cover. More than 50% of the salmon from 5 to 9 cm
moved into deeper water having moderate current (0.1 to 0.86 m/sec) and
less instream cover. Adult salmon used slower (less than 0.2 m/sec),
shallower sites with abundant instream cover for resting, and fast
velocity (0.6 to 1.1 m/sec), deeper sites with less instream cover for
feeding. Spawning salmon preferred shallower waters (0.1 to 0.39 m),
slower currents (0 to 0.3 m/sec), and small to moderate substrate sizes
« 25.6 cm). Microhabitat selection by Formosan landlocked salmon is
related to fish size, water temperature, and life history activities.
Key words: Salmon,
Microhabitat, Selection, Underwater observation.
*Correspondence: Current address: Department of Collection,
Taipei Zoo, 30, Sec. 2, Hsinkung Rd., Taipei, Taiwan 116, R.O.C. Tel:
886-2-29382300 ext. 204. Fax: 886-2-29382316. E-mail:
dwx07@mail.zoo.gov.tw
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