tow) and second most abundant in 46-54 m waters 

 (mean: 951/tow). Largest fishes were collected in 

 deepest waters. Trachypenaeus spp. and P. aztecus 

 catches were highest in 18-36 m waters, and both 

 species increased in size with increasing depth. 

 Sicyonia spp. catches were highest in 46-54 m waters 

 and lowest in 27-36 m waters. We found the highest 

 frequency of occurrence of Trachypenaeus spp. in 

 fish stomachs occurred in the same depth range (27- 

 36 m) as their maximum catch per tow. Predation 

 upon Sicyonia spp. was highest where these penaeids 

 were smallest and moderately abundant (27-45 m 

 depths). Predation upon P. aztecus was similar (low 

 to none) in all depth ranges. We also examined data 

 from 30 individual stations where relatively high catch- 

 es (exceeding 1,000 individuals/tow) of fishes or pe- 

 naeids were made. We postulated that if the fishes 

 were actively seeking penaeid prey, the frequency of 

 shrimps in fish stomachs from such stations would be 

 higher than the average frequency for all stations in 

 the corresponding depth range. However, we found 

 no indication that locally high abundances of shrimps 

 elicited greater predation by fishes nor any indica- 

 tion that concentrations of fishes at a given location 

 were preying more frequently on penaeids as com- 

 pared with the average predation frequency of a 

 given depth range. Apparently, the trawl-susceptible 

 fishes preyed in a nondirected, opportunistic manner 

 upon Trachypenaeus spp. and Sicyonia spp. which 

 were smaller and generally less abundant than P. 

 aztecus. 



A literature review revealed that the foods of 51 of 

 the 81 fish species examined here have been report- 

 ed previously to some degree, mainly from inshore 

 and estuarine studies. The major exception is the 

 work of Rogers (1977), as discussed in previous para- 

 graphs. Thirteen of the species we examined yielded 

 no data due to empty stomachs. Forty-seven species 

 were represented in our study by 25 or fewer indi- 

 viduals, and we categorize these data as preliminary 



until more specimens are analyzed. However, this 

 paper presents new information on the foods of 21 

 abundant Gulf of Mexico continental shelf fish spe- 

 cies by depth range and size class whenever pos- 

 sible. 



The analysis of fish stomach contents reported here 

 indicates that brown shrimp stocks are not subjected 

 to heavy predation pressure as the juveniles and sub- 

 adults migrate offshore. Fifty of the 81 species of 

 trawl-susceptible fishes we examined did not feed on 

 penaeid shrimps, and only 6 species had eaten brown 

 shrimp. The shrimp predators instead preferred 

 smaller penaeids, in part due to the small sizes of the 

 fishes, themselves. Future stomach contents studies, 

 in addition to analyses of trawl-susceptible fishes, 

 should include larger fishes captured by methods 

 such as long lines, gill nets, and fish trawls. 



Literature Cited 



Caillouet, C. W., and D. B. Koi. 



1981. Trends in ex-vessel value and size composition of 

 reported May-August catches of brown shrimp and white 

 shrimp from the Texas, Louisiana, Mississippi, and Ala- 

 bama coasts, 1960-1978. Gulf Res. Rep. 7:59-70. 



Gulf of Mexico Fishery Management Council. 



1980. Fishery management plan for the shrimp fishery of the 

 Gulf of Mexico. Fed. Regist. 45(218):74190-74308. 

 Matthews, G. A. 



1982. Relative abundance and size distributions of commer- 

 cially important shrimp during the 1981 Texas closure. 

 Mar. Fish. Rev. 44(9-10):5-15. 



Rogers, R. M., Jr. 



1977. Trophic interrelationships of selected fishes on the 

 continental shelf of the northern Gulf of Mexico. Ph.D. 

 Thesis, Texas A&M Univ., College Station, 244 p. 



Regbma Divita 



Mischelle Creel 



Peter F. Sheridan 



Southeast Fisheries Center Galveston Laboratory 

 National Marine Fisheries Service, NOAA 

 4700 Avenue U, Galveston, TX 77550. 



402 



