10t 



PRICKLY SCULPIN 



SACRAMENTO SUCKER 



I 982 



I 983 



FISHERY BULLETIN: VOL. 84, NO. 1 



TULE PERCH 



1988 



Figure 4— Capture rates of native resident species within Suisun Marsh. Mean catch per effort is described as percent of the total catch 



for each species. 



feeding species, delta smelt (native), longfin smelt 

 (native), and threadfin shad (introduced). All three 

 species tended to be most abundant in November 

 through January, although the pattern was not 

 always consistent (Fig. 6). Threadfin shad were the 

 most erratic of the three species in abundance; they 

 were especially abundant in the summer of 1981. 

 Longfin smelt were largely absent from our samples 

 in 1979 and 1981. Delta smelt abundance was 

 positively correlated (P < 0.05) with that of the other 

 two species, although the correlation between long- 

 fin smelt and threadfin shad was not significant. All 

 three species had negative correlations with tem- 

 perature, and positive correlations with Secchi 

 depth. 



The "spring/summer seasonals" were staghorn 

 sculpin and starry flounder, both euryhaline marine 

 species that were represented mainly by young-of- 

 year. Their patterns of abundance were not consis- 

 tent (Fig. 6) and the peaks occurred anytime from 

 March through September. Consequently, staghorn 



sculpin did not show any significant correlations with 

 the environmental variables, although starry 

 flounder did show negative correlation with Secchi 

 depth. Both species had a positive correlation with 

 species diversity, presumably because they were rare 

 in our samples during the last 2 years when the 

 marsh was dominated by freshwater. 



In addition to the 12 species that appeared regular- 

 ly in our trawls, there were a number of other species 

 of potential importance to the fish community that 

 were either not sampled adequately by the trawl or 

 were absent because of the effects of the 1976-77 

 drought. Five species that were not sampled ade- 

 quately were inland silverside, chinook salmon, 

 Sacramento squawfish, mosquitofish, and rainwater 

 killifish. The silversides were abundant year around 

 in the shallow, sandy or weedy areas found in some 

 sloughs. Silversides appeared in seine hauls in 20 of 

 the 22 mo in which seining was done; they were 

 generally the most abundant fish in these hauls. 

 Juvenile chinook salmon and squawfish were com- 



112 



