enter nursery areas through tidal passes, we estab- 

 hshed a sampling station at the entrance to Galves- 

 ton Bay in Xovember 1059. Additional stations 

 along Galveston Island's Gulf beach were added 

 later. 



GALVESTON ENTRANCE 



The initial sampling site was on the south side of 

 the entrance to Galveston Bay (station A, fig. 1), 



Galveston Entrance 

 'GALVESTON 



95 90 



TEXAS i LA 



Figure 1. — Galveston Island and environs, showing sampling 

 stations. 



where we collected postlarval shrimp twice each 

 week. This location was not suitable as a sampling 

 station after Hurricane Carla in September 19G1. 

 Thereafter, semiweckly samples were obtained from 

 station B, near the base of tlie north jettJ^ Bottom 

 materials at both stations consisted of well- 

 compacted sand. 



Collections of postlarvae were made with a 5-foot, 

 hand-drawn beam trawl fitted with a plankton net 

 at its cod end (Renfro, 1903). The wings of the 

 trawl consisted of nylon netting having 50 holes per 

 square centimeter. We believe that escapement 

 of postlarval shrimp was negligible, because most 

 collections contained an abundance of organisms 

 more minute than the smallest postlarvae captured. 

 To test whether or not large shrimp were evading 



the small beam trawl we towed a fine-mesh, 20-foot 

 seine on several occasions. A standard procedure 

 was followed during each collection. One end of a 

 1 50-foot line was tied to a stake driven into the sand 

 at the wafer's edge. The collector held the free entl 

 of this line in one hand and the bridle of the trawl in 

 the other and pulled the gear along the bottom in a 

 semicircular i)ath from the shoreline. 



GULF BEACH 



Collections of postlarval shrimp were made twice 

 each month between April 1960 and April 19()1 at 5- 

 mile intervals along Galveston Island's 25-miIe 

 beach (stations C, D, E, and F, fig. 1). The same 

 beam trawl was u-sed at beach stations, but because 

 of the surf, the sampling procedure was altered from 

 that used at stations A and B. The collector waded 

 a measured 75 yards directly offshore, set the gear, 

 and towed it back to shore. Computations of bot- 

 tom areas sampled were based on distance towed 

 and the dimensions of the net. 



At all stations we made meteorological and hydro- 

 graphic observations. Those that we consider to be 

 pertinent, namely water temperature, salinity, and 

 tidal stage, are listed in appendi.\ tables 1 and 2 

 along with the numbers of postlarval brown and 

 white shrimp collected on each sampling date. 



SEASONAL OCCURRENCE 

 GALVESTON ENTRANCE 



Postlarval brown shrimp, P. aztecus Ives, appeared 

 at Galveston I'^ntrance and migrated to the nursery 

 areas within Galveston Bay at about the same time 



WHITE SHRIMP 



t«0 SAMPLINC 



'/\ A, 



BROWN SHRIMP 



^ 



UX 



Yir.vRK 2. — Seasonal abundance of postlarval brown and 

 white shrimp at Galveston Entrance, 1000-6.'5. 



150 



U.S. FISH .A.ND WII.DLIKE t^?;RVICE 



