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2004 GR Report Summary
ADULT AND JUVENILE STEELHEAD POPULATION SURVEYS,
GUALALA RIVER, CALIFORNIA, 2004
Richard W. DeHaven
December 31, 2004
(Edited and Repaginated 01/2006)
SUMMARY: Steelhead spawning surveys (counts of adults and redds) initiated in 2002 along an 18.3-mile reach (index reach) of the Wheatfield Fork, from House Creek downstream to the South Fork, were continued in 2004. The index reach was surveyed eight times (146 miles) between January 17 and April 24 from small aluminum drift-boats. A total of 121 adult steelhead and 17 redds were recorded; adult numbers peaked during late March. Relatively high flows from December through March likely facilitated considerable spawning upstream of the index reach and reduced numbers of adults and redds recorded during the surveys; relatively low flows in April coincided with greatly reduced survey numbers compared to 2002. Results continued to indicate the need for weekly spawning surveys whenever possible, extended to bi-weekly surveys at the end of the spawning season and/or during extended dry conditions, for maximizing survey accuracy. Spawning survey data from 2004 will be coalesced with long-term results for later analysis and publication. In addition, between June 5 and November 7, six reconnaissance-level snorkeling surveys of juvenile steelhead (JSH), at roughly monthly intervals, were conducted at nine locations within the watershed. These initial JSH surveys, which will be used to design a long-term JSH-snorkeling protocol for implementation in 2005, showed that: (1) many reaches of the stream are water-temperature-impaired for JSH production; (2) due to the poor condition of the watershed and despite average rainy-season precipitation, extensive stream reaches are commonly dry or lack continuous surface flow by late summer; (3) Gualala roach (GR) and threespine stickleback (TSS) are the most common species found in association with JSH; (4) dramatic changes in presence of JSH, GR, and TSS occurred following the season’s first significant rainfall and runoff event in mid-October 2004; and (5) Wolf Creek is presently an important JSH rearing stream. Overall, 2004 likely provided excellent conditions for steelhead spawning, but relatively poor conditions for JSH rearing.
Senior Fish and Wildlife Biologist (Retired); U.S. Fish and Wildlife Service (Service), Sacramento, California. Recommended Report (available on CD from the author) Citation: DeHaven, R. W. 2004. Adult and juvenile steelhead population surveys, Gualala River, California, 2004. Prepared by the author (drdehave et hotmail.com), December 31, 2004, for use by agencies, groups and individuals involved in steelhead recovery efforts. 56 pp. (After March 1, 2007, report may be requested on CD from the author’s website at: http://www.gualalariversteelhead.info.) Disclaimer: These surveys and this report were self-funded and conducted during non-work hours, and not while in any official capacity as a biologist for the U. S. Fish and Wildlife Service.
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