Figure 20. — Hydrographic stations in Galveston Bay and the trawl station in the Galveston tidal pass, 1966. 



distribution, and (5) relations between tem- 

 perature, salinity, size, and abundance. 



Brown Shrimp 



To estimate relative abundance of emigrating 

 brown shrimp, we combined all shrinnp caught 

 in bottom and surface trawls during the day 

 and night. Two peaks of emigrationoccurred-- 

 the first in mid-May and the second in mid- 

 June. Because brown shrimp were leaving the 

 bay when we began sampling, we do not know 

 the magnitude of the first peak or when it 

 started. 



All shrimp caught in the tidal pass were 

 combined by weekly intervals to represent 

 the size of emigrating brown shrimp during 

 the study. Brown shrimp caught from May 14 

 to 21 had a mean length of 58.0 mm. (2.3 

 inches). Mean length was much greater (79.7 

 nnm.; 3.1 inches) the following week (May 22-28) 

 and tended to increase gradually for the rest 

 of the sampling period. 



A comparison of day and night catches be- 

 tween surface and bottom hauls indicated that 

 during ebb tides, emigrating brown shrinnp 

 remained close to the bottom during the day 

 and migrated vertically to surface waters at 



25 



