nothus (we found 12-187c occurrence in these spe- 

 cies); and roughback batfish, Ogcocephalus parvus, 

 shortwing searobin, Prionotus stearnsi, and sash 

 flounder, Trichopsetta ventralis (which we did not 

 examine). Rogers also identified Saurida and Anchoa 

 as primary prey species. 



Crabs occurred in the stomachs of 2 1 fish species 

 and, over all depths, were categorized as a major food 

 of bank sea bass, Centropristis ocyurus; smooth dog- 

 fish, Mustelis canis; sharksucker,£ , c/2e , neis naucrates; 

 and barred grunt, Conodon nobilis, though few in- 

 dividuals of the latter three species were examined. 

 In 9-17 m waters, crabs were a major food of hard- 

 head catfish, Arius felis, and large (>200 mm SL) 

 southern kingfish, Menticirrhus americanus. No ma- 

 jor crab predators were found in 18-45 m waters, but 

 crabs were a major food of rock sea bass, Centropris- 

 tis philadelphica, and Priacanthus arenatus in 46-64 

 m waters. Rogers (1977) noted that crabs occurred in 

 stomachs of 20 of the 26 fish species he examined but 

 comprised at least 20% by volume of the diets of only 

 3 species: Centropristis philadelphica; blackear bass, 

 Serranus atrobranchus; and ragged goby, Bollman- 

 nia communis 



Among other prey types, stomatopods were eaten 

 by 11 species, squid by 6 species, and holothurians 

 by 5 species. These taxa were occasionally major 

 foods of one or two species in a given depth range. 

 Polychaetes, molluscs, mysids, and octopi were also 

 found in fish stomachs, though only rarely. 



We found 38 species of shrimp predators from all 

 depths. Seventeen species were classified as having 

 shrimp as a major prey, but 9 of these were represen- 

 ted by data from fewer than 20 individuals. The 8 

 remaining species, in decreasing order of shrimp 

 occurrence in stomachs from all depths, included 

 Cynoscion arenarius; bighead searobin, Prionotus 

 tribulus; Diplectrum bivittatum; Prionotus rubio; 



southern hake, Urophycis floridana; star drum, Stelli- 

 fer lanceolatus; Priacanthus arenatus; and Centro- 

 pristis philadelphica. Shrimp were major foods of 

 Cyonscion nothus, C. arenarius, and Menticirrhus 

 americanus from the two shallower depth ranges (9- 

 26 m) and of Cynoscion nothus, Centropristis phila- 

 delphica, Diplectrum bivittatum, Urophycis floridana, 

 and lane snapper, Lutjanus synagris, from 27 to 64 

 m depths. The overall frequency of occurrence of 

 shrimps in fish stomachs increased from 13% in 9-17 

 m waters to 32% in 27-36 m waters, then declined to 

 4% in 55-64 m waters. Penaeid shrimps were iden- 

 tified in stomachs of 31 fish species. The penaeids 

 included Trachypenaeus spp. (302 occurrences in 28 

 species), Sicyonia spp. (52 occurrences in 13 spe- 

 cies), and Penaeus aztecus (13 occurrences in 6 spe- 

 cies). Rogers (1977) found shrimp in stomachs from 

 all 26 species examined, of which 8 species contained 

 at least 20% by volume of shrimps in their diets. 

 These included Prionotus rubio, Diplectrum bivit- 

 tatum, and Centropristis philadelphica (classified as 

 major shrimp predators by us); Serranus atro- 

 branchus and blackedge cusk-eel, Lepophidium 

 graellsi (classified as minor shrimp predators by us); 

 bay whiff, Citharichthys spilopterus (in which we 

 found no shrimp); and Syacium gunteri and speckled 

 trout, Cynoscion nebulosus (which we did not ex- 

 amine). Rogers frequently identified Trachypenaeus 

 spp. and Sicyonia spp., but did not find any Penaeus 

 aztecus in the 4,550 stomachs he examined. 



Species composition, abundance, and biomass data 

 for all fishes and invertebrates were recorded from 

 89 of the 108 trawl catches collected during the 

 shrimp survey. We compared the observed abun- 

 dances and distributions of fishes and penaeid 

 shrimps with our data on the occurrence of penaeids 

 in fish stomachs (Table 7). Fishes were most abun- 

 dant in the 9-17 m depth range (mean: 1,424/30-min 



TABLE 7 . — Comparison of catch per 30-min tow and size of fishes and penaeid shrimps by depth range with frequency 

 of occurrence of shrimps in fish stomachs from collections off the Texas coast between 4 June and 3 July 1981. N = 

 number of trawl-tows in each depth range. 



401 



