NOTE Rooper and Haldorson: Consumption of C/upea pa/lasi eggs by Hexagrammidae in Prince William Sound 657 



where C, = the total biomass of eggs con- 

 sumed per km'; 



B = the biomass of greenhng; 



C^i = the daily ration as a percentage 

 offish weight; and 



/ = the length of the incubation period 

 in d. 



This estimate of egg biomass consumed was 

 applied to the biomass estimates of eggs 

 spawned on Montague Island to obtain a per- 

 centage of the total herring eggs consumed by 

 greenling. 



Results 



30,000 



25.000 



20.000 



o) 15,000 



10,000 



5.000 



' Greenling 

 I Dolly Varden 



200 250 .100 .150 400 



Fork length (mm) 



450 



500 



Six fish species were caught during gillnet 

 sampling: rock greenling iHexagrammos lago- 

 cephalus), kelp greenling (Hexagrammos deca- 

 grammus), Dolly Varden char (Salveliruis mal- 

 ma), starry flounder iPlatichthys stellatiis). 

 red Irish lord {Hemilepidotus hemilepidotiis) 

 and great sculpin (Myoxocephalus polyacan- 

 thocephalus). The most common fish caught 

 were the two greenling species, followed by Dolly Varden 

 and great sculpin; only one red Irish lord and one starry 

 flounder were caught. Average catch for all species was 

 relatively low, ranging from 0.009 fish per h (SE=0.008) 

 for starry flounder and red Irish lord to 0.120 fish per h 

 (SE=0.0.52) for the greenling species combined (Table 1), 

 Only greenling and Dolly Varden consumed herring eggs; 

 all 13 greenling stomachs contained eggs, whereas just 4 

 of 8 Dolly Varden stomachs contained eggs. Stomachs of 

 other fish species contained a combination of unidentifi- 

 able fish and invertebrates. The average number of eggs 

 per stomach was 87 (SE=40.4) for Dolly Varden, and 8785 

 (SE=2107.6) for greenling. The number of herring eggs 



Figure 2 



Number of eggs per stomach for combined greenling species (n = 13l and 

 Dolly Varden char (;!=8) captured by gillnetting at herring spawning 

 bed transects in 1995. The line represents the predicted exponential 

 increase in eggs per stomach with increasing fork length; ;■- for the pre- 

 dicted versus the observed relationship was 0.55. 



per greenling stomach increased exponentially with length 

 (Fig. 2). 



A pattern in greenling and Dolly Varden catch distribu- 

 tions was apparent; Dolly Varden were caught exclusively 

 in embayments, whereas all greenling, except one, were 

 caught on the outer coast of Montague Island. The aver- 

 age temperature during incubation at -1..5 m depth was 

 5,8°C at transect 4, resulting in an estimated instanta- 

 neous evacuation rate of 0.057 per h. The daily ration cal- 

 culated with that evacuation rate was 11,984 eggs per d 

 (Table 2). 



Subtidal surveys of fish abundance in Prince William 

 Sound found an average of 0.0889 greenling per m-' on 



