Steelhead usable habitat area in the Sitkoh Creek watershed, 2005–2007

Alaska Department of Fish and Game, Fishery Data Series No. 12-31, Anchorage.

We conducted seasonal fish use snorkel surveys in the Sitkoh Creek watershed on Chichagof Island, in Southeast Alaska between 2005 and 2007.  For both adult and juvenile steelhead Oncorhynchus mykiss, we identified the stream reaches they occupied and calculated total usable habitat area.  Channel bed width and stream reach length were measured to approximate usable habitat area for adult and juvenile steelhead.  Adult steelhead were limited to mainstem reaches and occupied 12.72 ha of this habitat; juvenile steelhead utilized both mainstem and tributary reaches (n = 5), and were observed occupying a total of 15.42 ha across the watershed.  A 7-year stock assessment project at Sitkoh Creek found a mean adult escapement of 541 steelhead with juvenile emigration averaging 2,434 smolts.  When combined with this study, this production yields an estimate of 35 adult steelhead and 158 smolt per hectare of total usable habitat area.  This report completes the second phase of the project at Sitkoh Creek and the findings will be incorporated into a habitat-based steelhead carrying capacity model for Southeast Alaska.