was more than four times greater in Clear Lake. This trend for greater num- 

 bers of individuals but fewer numbers of species in the lower saline waters 

 as compared to the marine is characteristic. Unfortunately, these figures 

 are in terms of numbers, not biomass. The accompanying data show the total 

 catch of each of the 10 most abundant species in the trawl samples from Clear 

 Lake and Offatts Bayou during the period May I960 to April 1962. 



Both brown and white shrimp were considerably nnore abundant in 

 Clear Lake than in Offatts Bayou though their periods of abundance in the two 

 locations coincided closely. White shrimp show peaks in abundance in both 

 estuarine habitats during the month of September and low points during March. 

 Brown shrimp reach their greatest abundance in May and June and the least in 

 the month of January. Analysis of the accompanying figure reveals that both 

 species show a sharp decline in catch per unit of effort for 1961. This agrees 

 with Fish and Wildlife Service statistics and reports for both the bait shrimp 

 fishery and the regular commercial fishery. Sizes of the two species w^ere 

 comparable in both areas, ranging in the case of brow^n shrinnp from tiny 

 postlarvae to large juveniles (12. 5 g. , 115 mm. ) and, in the case of white 



/ 



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CLEAR LAKE 



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• - Wh't» ahfi 



2^ 



OFFATTS BAYOU 



y^- 



■\ 



MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR 

 I960 1961 1961 1962 



Monthly catch per 

 unit of effort for 

 brown and white 

 shrimp between 

 May I960 and 

 April 1962 in two 

 Galveston Bay 

 habitats. 



shrimp, from postlarvae to subadults (16. 5 g. , 130 mm. ). The smaller sizes 

 were relatively more abundant in Clear Lake, while Offatts Bayou samples con- 

 tained proportionally higher numbers of the larger sizes. 



The number of blue crabs taken in Offatts Bayou during the 24 months 

 of study was considerably less than that in Clear Lake. Immature or juvenile 

 crabs of both sexes made up the bulk of the Clear Lake catch. Mature individ- 

 uals, mostly males, made up the greater part of the Offatts Bayou catch. 



Finfish catches, with several exceptions, followed the same picture 

 of lower catches per unit of effort in Offatts Bayou than in Clear Lake. The 

 spot was the nnost abundant single species taken in Offatts Bayou, contrasting 

 with its rank of the fourth nnost common fish in Clear Lake. Catch -per -unit - 

 of -effort data compare fairly well in the two areas, but the peak of abundance 



50 



