DANIELS: FEEDING ECOLOGY OF ANTARCTIC FISHES 



Table 5.— Changes in diet by locality of capture in fishes of similar size and taken during the same sea- 

 son off the Antarctic Peninsula, 1975. A x 2 test for association was used to examine changes in the volume 

 of each taxon consumed; a Kruskal-Willas x 2 test was used to examine changes in feeding inten- 

 sity (fullness index). 



Table 6.— Size-related changes in diet in Antarctic fishes, Antarctic Peninsula, 1975. Fish in each 

 species were collected at the same time from the same locality. 



krill and Pleuragramma antarcticum from the 

 pelagic and cryopelagic communities, limpet 

 Patinigera polaris from rocky cliffs, and a large 

 number of organisms from rubble-bottom areas, 

 the habitat from which this species was most fre- 

 quently collected. Harpagifer bis pin is consumed 

 prey from the same taxa through the sampling 

 period, but the importance of each taxon differed 

 (x 2 = 149, df = 21, P<0.01). The significance re- 

 sults from a midwinter peak in abundance of 

 scaleworms. This species consumed organisms 

 from the rubble-bottom community which con- 

 sisted largely of the amphipods Bovallia gigantea, 

 Eurymera monticulosa, the scaleworm Har- 

 mothoe spinosa, and the isopods, Munna sp. and 

 Cymodocea antarctica. 



Differences in diet of similar-sized individuals 

 of Notothenia gibberifrons, N. nudifrons, N. 

 larseni, and T. scotti collected at the same 

 locality at different times of year were signifi- 

 cant in the relative importance of each prey 

 taxon, but tended to show no significance in the 



amount of food consumed (Table 7). In all four 

 species individuals tended to consume prey from 

 the same number of taxa. Spring samples tended 

 to contain individuals of a smaller size than late 

 summer samples. 



Dietary Similarity 



Diets were >60% similar in 17 species pairs by 

 number and in 11 species pairs by volume (Table 

 8). Similarity in diet by number of prey items 

 consumed is greater due to the large number of 

 amphipods taken by most fishes. A high 

 percentage similarity by volume, a value more 

 indicative of the importance of each food type, 

 was obtained for morphologically similar species 

 such as the two harpagiferids, A. scottsbergi 'and 

 Harpagifer bispinis, and the pelagic-benthope- 

 lagic complex of N. larseni, T. scotti, T. newnesi, 

 Pleuragramma antarcticum, and Cryothenia 

 peninsulae. Species that were generalists 

 showed 30-60% similarity in diet with other 



583 



