FISHERY BULLETIN: VOL. 74, NO. 3 



food densities, conserves its dwindling energy 

 resources by increased resting and vv'aiting for 

 prey to appear within its range. 



Hjort (1914, 1926) hypothesized that large-scale 

 mortality will result if the proper food is not 

 available in sufficient quantity at the "critical 

 period" when newly hatched fish larvae require 

 their first feeding, and that the numerical 

 strength of a year class, therefore, might be 

 determined at this time. The increasingly thin 

 shape of young ocean-caught anchovy larvae 

 suggests that feeding problems may exist for 

 sometime into the larval period. Saville (1971) 

 proposed that a "critical stage" might occur at any 

 stage between hatching and metamorphosis and 

 that the detection of same would allow one to 

 specify the earliest stage at which reliable indices 

 of year-class strength could be determined. The 

 end of the decline in relative body depth of the 

 average ocean-caught larva might mark the point 

 in the larva's development when the danger of 

 starvation has diminished and perhaps, as sug- 

 gested by Saville, is the earliest stage at which 

 estimates of recruitment might be made. 



ACKNOWLEDGMENTS 



I express my appreciation to Reuben Lasker, 

 John R. Hunter, and Martin W. Johnson for their 

 helpful comments and criticisms during the 

 preparation of the manuscript. Elbert H. Ahlstrom 

 and Paul E. Smith also furnished valuable sug- 

 gestions and information. I am indebted to the 

 Southwest Fisheries Center La Jolla Laboratory, 

 National Marine Fisheries Service, NOAA, for the 

 use of facilities and especially to Reuben Lasker 

 who provided working space and the use of his 

 personal library. I also convey my gratitude to 

 Martin W. Johnson and Carl L. Hubbs for their 

 guidance in the research leading to the completion 

 of the thesis upon which this paper is largely 

 based. 



LITERATURE CITED 



Ahlstrom, E. H. 



1954. Distribution and abundance of egg and larval popula- 

 tions of the Pacific sardine. U.S. Fish Wildl. Serv., Fish. 

 Bull. 56:83-140. 

 1967. Co-occurrences of sardine and anchovy larvae in the 

 California Current region off California and Baja Califor- 

 nia. Calif. Coop. Oceanic Fish. Invest. Rep. 11:117-135. 

 Arthur, D. K. 



1956. The particulate food and the food resources of the 



larvae of three pelagic fishes, especially the Pacific sardine, 

 Sardinops caerulea (Girard). Ph.D. Thesis, Univ. Califor- 

 nia, Scripps Inst. Oceanogr., La Jolla, 231 p. 



Bainbridge, v., and D. C. T. Forsyth. 



1971. The feeding of herring larvae in the Clyde. Rapp. 

 P.-V. Reun. Cons. Int. Explor. Mer 160:104-113. 



Beers, J. R., and G. L. Stewart. 



1970. Numerical abundance and estimated biomass of 

 microzooplankton. In J. D. H. Strickland (editor). The 

 ecology of the plankton off La Jolla, California, in the 

 period April through September, 1967, p. 67-87. Bull. 

 Scripps Inst. Oceanogr. Univ. Calif. 17. 



Berner, L., Jr. 



1959. The food of the larvae of the northern anchovy 

 Engraulis mordax. Inter-Am. Trop. Tuna Comm., Bull. 

 4:3-22. 

 Blaxter, J. H. S. 



1965. The feeding of herring larvae and their ecology in 

 relation to feeding. Calif. Coop. Oceanic Fish. Invest. Rep. 

 10:79-88. 



1971. Feeding and condition of Clyde herring lar\ae. Rapp. 

 P-V. Reun. Cons. Int. Explor. Mer 160:128-136. 



Blaxter, J. H. S., and K. F. Ehrlich. 



1974. Changes in behaviour during star\'ation of herring 

 and plaice larvae. In J. H. S. Blaxter (editor), The early 

 life history of fish, p. 575-588. Springer-Verlag, Berl. 

 Blaxter, J. H. S., and M. E. Staines. 



1971. Food searching potential in marine fish larvae. In D. 

 J. Crisp (editor). Fourth European Marine Biology Sym- 

 posium, p. 467-485. Cambridge Univ. Press. 

 BOLIN, R. L. 



1936. Embryonic and early larval stages of the California 

 anchovy, Engraulis mordax Girard. Calif Fish Game 

 22:314-321. 

 Bowers, A. B., and D. I. Williamson. 



1951. Food of larval and early post-larval stages of au- 

 tumn-spawned herring in Manx waters. Annu. Rep. Mar. 

 Biol. Stn. Port Erin 63:17-26. 

 BURDICK, J. E. 



1969. The feeding habits of neju (Hawiian anchovy) lar- 

 vae. M.S. Thesis, Univ. Hawaii, 54 p. 

 ClECHOMSKI, J. D. de. 



1965. Observaciones sobre la reproduccion, desarrollo em- 

 brionario y larval de la anchoi'ta argentina {Engraulis 

 anchoita). Bol. Inst. Biol. Mar. Mar del Plata 9, 29 p. 

 1967. Investigations of food and feeding habits of larvae 

 and juveniles of the Argentine anchovy Engraulis an- 

 choita. Calif. Coop. Oceanic Fish. Invest. Rep. 11:72-81. 



ClECHOMSKI, J. D. DE, AND G. WeISS. 



1974. Estudios sobre la alimentacion de larvas de la merluza, 

 Merluccius merluccius hubbsi y de la anchoita, Engraulis 

 anchoita en la mar. Physis Rev. Asoc. Argent. Cienc. Nat. 

 33:199-208. 



Detwyler, R., and E. D. Houde. 



1970. Food selection by laboratory-reared larvae of the 

 scaled sardine Harengula pensacolae (Pisces, Clupeidae) 

 and the bay anchovy Anchoa mitchilli (Pisces, En- 

 graulidae). Mar. Biol. (Berl.) 7:214-222. 



DUKA, L. A. 



1967. Struktura I dinamika soobshchestv (Adaptive fea- 

 tures in the feeding of pelagic larvae of fish living in 

 different ecological conditions). Akad. Nauk Ukr. SSR, p. 

 136-143. (Translated by Natl. Lending Libr. Transl. Pro- 

 gram RTS 5162.) 



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