| Introduction | Creek Description | Rotenone Treatment | Procedure | Species | Discussion |

Results

Small numbers of all native species apparantly survived the rotenone treatment in refugia along the treated zone; all species had been reported in at least small numbers by 1993.

Although the sampling technique permits estimation of numbers and biomass in the sample sites, the associated statistical bounds were often large. Rather than comparing imprecise population estimates, it seems more meaningful to compare the size distribution of fish actually captured at each site. Since collection techniques were comparable from 1987 to 1996, relative numbers in different years can also be compared. The 1986 data, which were collected in the same sites, but by a different method (collection of total kill) would be expected to yield slightly higher numbers as compared with subsequent years. The 1984 data is the least comparable, since the sites sampled did not exactly correspond (areas were larger but included some deeper pools where electrofishing was less effective) and at the lower (detox) site many small, non-game fish were not measured.

In interpreting data for the large cyprinoid fishes (Sacramento sucker, Sacramento squawfish, and hardhead), keep in mind that these fish travel in shoals which move from pool to pool in the creek. Getting many large ones (or no large ones) on a given sampling date is partly a function of whether or not a shoal chanced to be in the sampling site, particularly when the creek population is low. (Hardhead data for the detox site provides an excellent example.)

Data and descriptions are presented for individual species:

FamilyCommon NameSci NameDescriptionData
SalmonidaeSteelhead Rainbow Trout Oncorhynchus mykissDescriptionDATA
*Brown TroutSalmo truttaDescriptionDATA
CyprinidaeHardhead Mylopharodon conocephalusDescriptionDATA
Sacramento Squawfish Ptychocheilus grandisDescriptionDATA
California Roach Hesperoleucas symmetricusDescriptionDATA
CatostomidaeSacramento Sucker Catostomus occidentalisDescriptionDATA
Centrarchidae*Green Sunfish Lepomis cyanellusDescriptionDATA
*Smallmouth Bass Micropterus dolomieuiDescriptionDATA
CottidaeRiffle Sculpin Cottus gulosus DescriptionDATA
* Introduced species.


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Results Last Updated September 21, 1996

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