HACUNDA: TROPHIC RELATIONSHIPS AMONG DEMERSAL FISHES 



Table 3. — Stomach contents of 37 windowpane ranging from 

 21.0 to 33.6 cm (mean 27.3 ±3.3 cm) and 90 to 482 g (mean 

 244 ±90 gi. Eight .stomachs were empty. IRI = index of relative 

 importance (see text). 



Percentage 



Taxon 



Weight Number Frequency' IRI 



Polychaeta total 0.13 0.06 2 70 1 



Crustacea total 79.27 98.99 75.68 13.490 



Mysidacea total 78.78 98.74 75.68 13^434 



Neomysis americana 1.16 2.46 8 11 29 



Mysis mixta 72.41 94,65 59.46 9,933 



Other Mysidacea 5.21 1.63 



Amphipoda total .26 .19 8 11 4 



Decapod total .23 06 2.70 1 



Pisces Clupea h harengus 20.25 94 2.70 57 



Remains 0.36 



Grand total 100.00 100,00 



' Frequency of occurrence of food item. 



almost half the diet by weight (48.5%) and almost 

 the entire diet by number (95.1%) (Table 4). Am- 

 phipods were the most important crustaceans con- 

 sumed, followed by mysids, cumaceans, and deca- 

 pods. Unciola sp. was the principal amphipod prey, 

 making up 28.7% of the diet by weight and 82.0% 

 of the diet by number. The amphipod Leptocheirus 



Table 4. — Stomach contents of 60 yellowtail flounder ranging 

 from 19.0 to 42.0 cm (mean 30.9 + 7.2 cm) and 42-670 g (mean 

 280 ±174 g). Fourteen stomachs were empty. IRI = index of 

 relative importance i see text). 



Percentage 



pinguis and mysid Mysis mixta were also impor- 

 tant. After Crustacea, polychaetes (10.2% of the 

 diet by weight) and mollusks (5.2% of the diet by 

 weight) were the next largest dietary components. 

 The bivalve Cerastoderma pinnulatum was a sig- 

 nificant prey item. Other prey groups (Nemertea, 

 Echinodermata, Pisces I were of minor importance. 



Ocean Pout 



Twenty-seven prey taxa were found in the 46 

 ocean pout stomachs. A comparison of the relative 

 contributions of echinoderms and crustaceans to 

 the diet showed that echinoderms were the most 

 important prey group in terms of percent weight 

 (20.6% vs. 13.7%), while crustaceans had a greater 

 IRI (7,382 vs. 974) (Table 5). Amphipods and, to a 

 lesser extent, cumaceans were the principal crus- 

 tacean orders present in the ocean pout diet. The 

 amphipods Unciola sp. and Leptocheirus pinguis 

 and the cumacean Diastylis quadrispinosa were 

 significant prey. Principal echinoderm prey were 

 the sea urchin, Strongylocentrotus droebachien- 

 sis; the sand dollar, Echinarachnius parma; and 



Table 5. — Stomach contents of 46 ocean pout ranging from 18.2 

 to 49.0 cm (mean 34.3 ±5.9 cm) and 24 to 660 g( mean 214 ±11.8 

 g). Five stomachs were empty. IRI = index of relative impor- 

 tgmce (see text). 



'Frequency of occurrence of food item. 



' Frequency of occurrence of food item. 



779 



