FISHERY BULLETIN: VOL. 73, NO. 1 



.UTILIZABLE 



SPECIES 

 / (39.0%)/ 



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UTILIZABLE 



SPECIES 

 /(24.8 %) 



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UTILIZABLE^ 



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SPECIES 

 ( 58J%) 



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UTILIZABLE 



SPECIES 



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UTILIZASLf 

 SPECIES 

 1»3 9%) 



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 SPECIES / 

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JUNE 



SEPTEMBER SUMMARY 

 HOT SEASON 



JULY 



SEPTEMBER SUMMARY 



HOT SEASON 



SEPTEMBER SUMMARY 



HOT SEASON 



SAN CARLOS CREEK 



BROWNS CREEK 



Figure 3. — Densities of fishes in the three creeks as estimated from seine collections. Species used by man as food or fishery products 

 are combined and termed Utilizable Species. Percent of each collection that was represented by utilizable species is indicated. 

 Cyprinod = all species of Cyprinodontidae. Gerreid = all species of Gerreidae except for Gerres cinereus . The histogram for each creek 

 depicting "Summary Hot Season" was compiled on the basis of the total area sampled during the entire study period. 



fishes in Browns Creek was three to four times 

 higher than the estimated density in San Carlos 

 Creek. However, in September the estimated den- 

 sity in San Carlos Creek was about three times 

 higher than that in Browns Creek. The basis for 

 this apparent September reversal between the two 

 creeks was due primarily to the expected early fall 

 emigration of juveniles of migratory species, 

 many of which are utilizable species. The esti- 

 mated density of total fishes in Browns Creek was 

 two to four times higher than the density in 

 Nichols Creek throughout the entire study period. 

 Of greater significance than the differences in 

 total density of fishes described above, are the 

 marked differences that existed between creeks in 



the estimated densities of utilizable species (see 

 Figure 3). In June and July, the estimated density 

 of utilizable species in Browns Creek was seven to 

 eight times greater than in San Carlos Creek. In 

 September following the emigration of juveniles of 

 many migratory species, the estimated density of 

 utilizable species in Browns Creek was still nearly 

 five times greater than that recorded in San Car- 

 los Creek. When data for the entire hot season are 

 pooled. Browns Creek displayed an overall density 

 of utilizable species approximately nine times 

 greater than that in San Carlos Creek. In Nichols 

 Creek the estimated densities of utilizable species 

 were generally somewhat higher than those in 

 San Carlos Creek yet markedly lower than those 



74 



