Ceriantharia (2.8%). The remaining half of the stomach contents 

 was distributed between the other seven major prey groupings with 

 unidentified animal remains alone accounting for 16.1% of the 

 di^t. Of the taxonomically distinct groups, the MoUusca were the 

 most important (15.7%), but unfortunately most of these (14.7%) 

 were unidentified bivalves. However, the 1 % of the molluscan part 

 of the diet that was identified was attributed to 1 1 genera of bivalves 

 aiid 10 genera of gastropods. Arthropods were the only other large 

 taxon to contribute >1% to the diet. Within the arthropods, the 

 most important crustaceans were Amphipoda (3 . 1 %). A number of 

 genera and species were identified but those contributing > 0. 1 % to 

 the diet were Aeginina longtomis (0.6%), Gammarus annulatus 

 (0.5%), Leptocheirus pinguis (0.4%), and Pontogeneia inermis 

 (0. 1 %). The only other animals of any significance in the diet were 

 the crustaceans [Crangon septemspinosa (0.7%), Cancer irroratus 

 (0.6%), Pagurus (0.2%)], the sea cucumber [Stereoderma 

 unisemita (0.5%)], and the tunicate [Amaroucium (0.3%)]. 



Geographic Comparisons 



Gulf Stream flounder. — Gulf Stream flounder were collected in 

 the Middle Atlantic, Southern New England, and on Georges Bank 

 (Table 2). 



In the Middle Atlantic, arthropods accounted for half (49.5%) of 

 the diet, with the Amphipoda (16.3%) and the Euphausiacea 

 (14.1%) being the two most important groups. A variety of 

 amphipods were identified in the stomach contents, and the most 

 important are: Byblis serrata (6.1%), several species of Unciola 

 (3.7%) [U. inermis (1.1%), U. /rrorato (1.4%)], and Erichthonius 

 rubricomis (1.4%). Most of the euphausiid prey was Meganyc- 

 tiphanes norvegica (11.3%); the remainder of the euphausiids 

 (2.8%) were unidentified. Other arthropods of some importance 

 were the crab. Cancer (7.6%) [C. irroratus (5.2%)]; the sand 

 shrimp, Crangon septemspinosa (5.4%); and the isopod, Edotea 

 triloba {1. 2Vo). In Southern New England arthropods accounted 

 for one-third of the diet (34.5%), and, as in the other areas, the 

 Amphipoda (21.9%) were extremely important. The amphipods 

 contributing most to the diet were Leptocheirus pinguis (l .1%), 

 Casco bigelowi (AAVa), Ampelisca spp. (4.0%) [A. agassizi (\ ■'iVo)], 

 and Unciola (3.9%). Other arthropod prey such as the 

 cumaceans, Diastylis spp. (2.9%) [D. quadrispinosa (0.6%); D. 

 sculpta (<0.1%)], and the euphausiids, Thysanoessa inermis 

 ( 1 .2%) and Meganyctiphanes norvegica (0.4%), also contributed to 

 the diet. On Georges Bank, the Arthropoda were the primary prey 

 (68.5%), with the Amphipoda accounting for 41.4% of the diet. A 

 single species of amphipod, Erichthonius rubricomis, made up half 

 (22. 1 %) of the amphipod prey. This same species had been preyed 

 on in both the Middle Atlantic (1.4%) and in Southern New 

 England (0.1%) but occurred much less frequentiy in the stomachs 

 examined. Apart from E. rubricomis, the Ampeliscidae were the 

 other amphipods of any significance, and, within this family, 

 Ampelisca agassizi (3.0%) was of major importance. Other arthro- 

 pods that were important prey on a weight basis were Dichelopan- 

 dalus feprooe/Ttf (12.3%), Mysidopsis bigelowi {2.9''Io), copepods of 

 the genus Centropages (2.0%), Thysanoessa gregaria (1.2%), and 

 Crangon septemspinosa {1.0%). Only one pandalid shrimp, D. lep- 

 tocerus, was foimd in the 53 Gulf Stream flounder stomachs exam- 

 ined, thus the estimate of its importance is imprecise. 



In the Middle Atlantic the annelid prey was exclusively 

 polychaetes representing a variety of different families. The most 

 important family was the Nephtyidae (12.8%), with Nephtys picta 

 (3.3%) having been identified at a species level. The Maldanidae 



Table 2. — Geographic breakdown of (he stomach contents of Gulf Stream 

 flounder, Citharkhthys arcrifrorn. in the nortbHest Atlantic. Data are expressed 

 as a percentage weight for fish collected during the spring and autumn bottom 

 trawl survey cruises, 1969-72. ( + indicates present but <0.1%.) 



were also important, but none of these polychaetes were identified 

 below the family level. Families and species classified under "Other 

 Annelida" that contributed significantly to the diet were the 

 Onuphidae (5.0%) [Onuphis conchylega (4.9%)], the 

 Flabelligeridae (4.7%) [Pherusa (0.1%)], and the Stemaspidae 

 (2.3%) [Stemaspis scutata (2.3%)]. In Southern New England 

 annelids were the major prey of Gulf Stream flounder. Virtually all 

 the annelids were polychaetes, although < 0.2% of this phylum 

 were identified as oligochaetes. A number of polychaete families 

 were represented in the stomach contents, and, as in the Middle 



