NOTE Graver and Olla Food habits of larval Anoplopoma fimbria from the Bering Sea 



813 



of females. However, since the number of copepod eggs 

 in tlie diet appeared to be positively correlated with 

 the number of adult Psei((localanuf> sp. ingested, we 

 conclude that most copepod eggs were probably at- 

 tached to adult female Pseudocalanus sp. when they 

 were ingested. The mechanical action of ingestion most 

 likely liberated the eggs from their delicate egg sacs 

 (see Grover 1990). These data suggest that copepod 

 eggs may be important in the diets of larval sablefish 

 and other species in the Bering Sea. 



In contrast to the larval diet off Oregon and Wash- 

 ington, copepods >2 mm were inconsequential in the 

 diet of larvae in the Bering Sea. While copepod species 

 with southern affinities were absent from the diet of 

 sablefish larvae collected in the Bering Sea, species 

 with northern affinities, i.e., Pseudocalanus sp. and A. 

 longiremis, occurred more frequently in the diet of lar- 

 vae collected in the Bering Sea than off Oregon (Grover 

 and Olla 1987). Euphausiid larvae, appendicularians, 

 and pteropods were absent from the diet of sablefish 

 larvae collected in the Bering Sea, while they made a 

 noticeable contribution to the diet of sablefish larvae 

 collected off Oregon. 



Specific differences in prey items could be expected 

 when comparing geogi'aphically separated populations; 

 however underlying principles of prey-size selection are 

 assumed to be universal in nature (Hunter 1981). We 

 looked beyond the initial data plots and found a bio- 

 logical explanation as to why the size of prey consumed 

 by large larvae in the Bering Sea differed from the pat- 

 tern observed off Oregon (Grover and Olla 1986). Our 

 data revealed that copepod eggs have such a confound- 

 ing influence on prey-size distributions that the mode 



of their ingestion (i.e., free-floating vs. attached to 

 adults) must be recognized in order to adequately in- 

 terpret prey-size selection patterns. 



Acknowledgments 



We wish to thank C.B. Miller for sharing his knowledge 

 of copepod biology, and Art Kendall for his continued 

 interest in the early life history of this species. 



This work was supported by the Northwest and 

 Alaska Fisheries Center, National Marine Fisheries 

 Service, NOAA, Contract Nos. NA-85-ABH-00025 and 

 NA-89-ABH-00039. 



Citations 



Corkett. C.J., and I. A. McLaren 



1978 The hiohgy- of Pspiiiiocnlarius. Adv. IVIar. Biol. 15:1-231. 

 Checkley, D.M. Jr. 



1980 The egg production of a marine planktonic copepod in 

 relation to its food supply: Laboratory studies. Limnol. 

 Oceanogr. 25:430-446. 

 Conover, W.J. 



1980 Practical nonparametric statistics. 2d ed. John Wiley 

 and Sons, NY, 493 p. 

 Grover, J.J. 



1990 Feeding ecology of late-larval and early-juvenile walleye 

 pollock Theragra chalcogrammn from the Gulf of Alaska in 

 1987. Fish. Bull., U.S. 88:46.3-470. 

 Grover. J.J., and B.L. Olla 



1986 Morphological evidence for starvation and prey size 

 selection of sea-caught larval sablefish, Anuplopumafimhna. 

 Fi.sh. Bull., U.S. 84:484-489. 



