652 



Fishery Bulletin 92(3). 1994 



the primary productivity of the Bank adequately ac- 

 counted for fish production only if a trophic transfer 

 efficiency of greater than 10% was assumed. This 

 may be a valid assumption for the model at the 

 trophic level of the northern sand lance. 



Zooplankton 

 Sand Lance 



rO.08 



0.06 



0.04 



02 



c 



TO 

 ■D 



I! 



n 

 to c 



0.00 



1977 1979 



1981 1983 

 Year 



1985 1987 



Figure 1 



Average annual copepod abundance of Calanus 

 finmarchicus, Pseudocalanus minutus, Centropages 

 hamatus, C. typicus, Metridia lucens, and of adult 

 northern sand lance, Ammodytes dubius, on Georges 

 Bank from 1977 through 1986. 



In their budget of Georges Bank bioenergetics, 

 Sissenwine et al. (1984) place sand lance in their 

 "other finfish" compartment (all nonfished species 

 that are vulnerable to fishing gear). From 1973 to 

 1975 a consumption of 9.3 kcalm~ 2 y _1 was attrib- 

 uted to this category. Sissenwine et al. (1984) sug- 

 gested that the impact of the sand lance population 

 was underestimated in their budget, and it appears 

 from the present study, based on the individual en- 

 ergy budget and population size, that this error was 

 potentially significant. By converting population 

 energetic consumption on Georges Bank (Table 6) to 

 consumption per square meter (assuming a mean 

 depth on the Bank of 50 m; Backus and Bourne, 

 1987), sand lance consumed from 8.5 to 203.5 kcal- 

 m -2. v -i f rom 1977 to 1986. This represents nearly all 

 the consumption attributed to the "other finfish" at 

 low northern sand lance abundances and over 20 

 times the total "other finfish" consumption at high 

 northern sand lance abundances. The results of this 

 study suggest that the budget estimates of annual 

 consumption by exploitable but commercially unde- 

 sirable fishes may need to be revised upward. 



Acknowledgments 



Special thanks to Ken Sherman, director of the 

 Narragansett Lab of the National Marine Fisheries 

 Service, for his enthusiasm and assistance in intro- 

 ducing me to his associates, Jack Green and Mike 

 Fogarty, who provided me with the most up to date 

 population data for zooplankton and sand lance on 

 Georges Bank. The Ph.D. dissertation in which this 

 study is detailed is cataloged at the Univ. Rhode Is- 

 land under the name S. Larimer. 



Literature cited 



Adams, S. M. 



1976. The ecology of eelgrass, Zostera marina I L. I, 

 fish communities. II: Functional analysis. J. exp. 

 Mar. Biol. Ecol. 22:293-311. 

 Backus, R. H., and D. W. Bourne (eds.). 



1987. Georges Bank. M.I.T. Press, Cambridge, 

 MA, 593 p. 

 Bigelow, H. B., and W. C. Schroeder. 



1953. Fishes of the Gulf of Maine. Fish. Bull. Fish 

 and Wildl. Ser. 53, 577 p. 

 Bowman, R. E., and W. Michaels. 



1981. Food habits of seventeen species of northwest 

 Atlantic fish. NOAA Tech. Memo. NMFS-F/NEC-28. 

 Brett, J. R., and T. D. D. Groves. 



1979. Physiological energetics. In W. S. Hoar, D. 

 J. Randall, and J. R. Brett (eds.), Fish physiology, 

 Vol. 8. Academic Press, 786 p. 



