614 



Fishery Bulletin 92(3). 1994 



tially consistent. The parallel temporal relationship 

 of the contribution of the anemone C. americanus to 

 overall benthic biomass and to winter flounder diets 



Station R2 



7 8 9101112 12 3 4 5 6 7 8 9101112 123456789101112 123456789 



[ 86 I 87 88 I 89 I 



collection periods 



stomach volume 



benthic biomass 



Station NY6 



100 



7 8 9101112 12 3 4 5 6 7 8 9101112 12 3 4 5 6 7 8 9101112 123456789 

 86 I 87 88 89 



collection periods 



stomach volume 



benthic biomass 



Station NY11 



7 8 9101112 12 3 4 5 6 7 8 9101112 12 3 4 5 6 7 8 9101112 1 23456789 

 86 87 88 89 



collection periods 



stomach volume 



benthic biomass 



at stations R2 and NY6 (Fig. 2) suggests a propor- 

 tional consumption association. The forage ratio in- 

 dices iK) for this prey are near zero (0.03 to 0.18, 

 Table 3); these suggest that winter flounder 

 neither preferred nor avoided this prey, con- 

 suming it at a level closely related to its avail- 

 ability at these two stations. Although, this 

 relation was more variable at station NY11 

 (Fig. 2), a moderately high, positive K value 

 (0.63 ) suggests some preference for this prey 

 (Table 3). 



The proportional consumption differences 

 (Fig. 3) and strong positive K values at each 

 station for P. affinis (Table 3) strongly sug- 

 gest that winter flounder have a preference 

 for this prey. Heavy predation on P. affinis 

 may be energetically advantageous to win- 

 ter flounder because this species has a high 

 caloric equivalence ( x =1.9 Kcal/g wet weight; 

 Steimle and Terranova, 1985). This is about 

 double that of other major prey, which range 

 from 0.9 to 1.1 Kcal/g wet weight, although 

 some amphipod species, such as U. irrorata 

 (consumed to a minor extent), are equally 

 energy rich (Steimle and Terranova, 1985). 

 The energy content of prey has been dis- 

 cussed as an important consideration in op- 

 timum foraging theories ( Mangel and Clark, 

 1986) and the winter flounder preference for 

 this high energy prey provides support for 

 these theories. It is also possible that prefer- 

 ence for this prey is related to the long-term 

 dominance of P. affinis in the macrofauna of 

 siltier areas of the New York Bight apex, as 

 this relatively productive species has been 

 common in the area and has been preyed 

 upon since at least the mid-1960s (Steimle 

 and Stone, 1973; Steimle, 1985, 1990; Steimle 

 et al., 1990). This extended period of domi- 

 nance may have contributed to winter floun- 

 der becoming experienced predators on this 

 species (and other abundant prey species) 

 and thus maintaining the preference 

 (Gendron, 1987). 



Figure 3 



Trends in the percent contribution of the poly- 

 chaete Pherusa affinis to total stomach volume 

 of winter flounder, Pleuronectes americanus, com- 

 pared to the polychaete's percentage contribution 

 of the total benthic macrofaunal biomass at three 

 sites in the New York Bight apex variably affected 

 by sewage sludge disposal. 



