102 



Fishery Bulletin 89(1), 1991 



5 10 15 



Nautical Miles 



Figure 1 



Location of sampling area off Free- 

 port, Texas. 



and 100m after May 1979. Collections were made dur- 

 ing the day through September 1978; thereafter, a day 

 and a night cruise usually were made each month. 

 Usually two tows, consisting of 10 minutes of bottom 

 time, were made at each depth. Exceptions were 8 tows 

 made at 16m, and 24 tows made at 22 m, and only one 

 tow made at most depths prior to October 1978. Our 

 spatial sampling design was a single cross-shelf tran- 

 sect from a sampling frame that encompassed much 

 of the northern Gulf. 



All P. burti were culled from the catch, measured for 

 total length (TL), fixed in 10% formalin for 2-4 days, 

 and then stored in 70% ethanol. For the period De- 

 cember 1978-November 1979 a total of 300 fish, if 

 available, was selected each month after stratifying the 

 catch into cohorts determined by length-frequency 

 analysis (see below). Specimens were then randomly 

 selected within strata to determine total length, fork 

 length (FL), standard length (SL), total weight (TW), 

 gonad weight (GW), and girth (G) measured vertically 

 from the dorsal fin to the preanal pterygiophore. Sagit- 

 tal otoliths were removed from individuals larger than 

 75 mm, teased free of saccular and labyrinthian tissue, 

 and then stored dry for later immersion in water and 

 viewing with reflected light under a dissecting micro- 

 scope. Female and immature fish were assigned gonad 

 maturity stages (Table 1) modified from Kesteven's 

 system (Bagenal and Braum 1971). Gonad weight and 



