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Fishery Bulletin 107(1 ) 
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Figure t 
Map of the Texas coastline identifying major bay systems and offshore sampling areas routinely 
monitored by the Coastal Fisheries Division of the Texas Parks and Wildlife Department. 
Major bays are labeled by name, gulf areas discussed in the text are indicated by a shaded 
area and are labeled (A-E). 
collected/hr) and served as a form of catch per unit of 
effort. Temporal variation in abundance was assessed 
from data by averaging the abundance of all trawls 
within a given season within a year and then averaging 
across all twenty years, and these results represented 
our temporal investigation. Seasons were designated as 
a three-month group: fall (October-December), winter 
( January-March), spring (April-June), and summer 
( July-September). In addition we recorded the mean 
total length (TL, mm) of each species and the follow- 
ing environmental variables: water temperature (°C) 
at depth of trawl (0.3 m off bottom); salinity (psu); and 
water depth (m) with each trawl. 
Distribution of sand seatrout and silver seatrout 
The abundance of sand seatrout and silver seatrout 
among offshore sampling areas was analyzed to deter- 
mine 1) overall abundance of each species, within each 
gulf area, and 2) seasonal and species differentiation 
among gulf areas. First, overall differences in abun- 
dance between species were tested by using a t-test for 
species mean abundance (averaged over all years) at 
each gulf area. Then, a three-factor ANOVA was used, 
involving the following factors: gulf areas (n- 5; all 
offshore sampling areas); seasons (n = 4; all seasons); 
and species (n= 2; both species) with all interactions. 
Species abundance was then correlated against each 
environmental variable by using Pearson correlation 
coefficients for each gulf area and season to determine 
the significance of the regressions. 
Length-frequency histograms were created from the 
twenty-year data set by using catch-length data set, 
separated by month, and averaged over years for in- 
dividual species collected across offshore areas. These 
histograms were created by partitioning individuals 
into 10-mm (TL) size classes and were used to describe 
cohort strength between species, by month. 
Distribution of sand seatrout inshore 
The abundance of sand seatrout at combined gulf areas 
(offshore) and at major bays (inshore) was analyzed to 
identify any spatial and temporal differentiation. To this 
end a two-factor ANOVA was employed involving the fac- 
tors: location (n= 2; combined gulf areas and combined 
