FISHERY BULLETIN: VOL. 73, NO. 1 



National Marine Fisheries Service, NOAA, pers. 

 commun.) are higher than three of our four larval 

 ration estimates (Table 7). Our menhaden ration 

 of 1.18 calories/fish day was 4(y7c of the 3.0 

 calculated from Hoss and Hettler's measurements 

 of respiration rate, indicating that for this species 

 our estimate is probably low. Our pinfish ration 

 was also lower, being 527c of that calculated 

 from the O2 consumption method. Our menhaden 

 estimate is highly dependent on a very tentative 

 factor used to adjust for handling effects. More 

 accurate measurement of this conversion factor 

 would probably provide better correlation with 

 metabolic costs. Our 1972 spot ration was 66% 

 of maintenance needs and may be indicative 

 (as with pinfish and menhaden) of natural food 

 shortages or environmental conditions not 

 optimal for feeding on the dates of collection in 

 1972. The 1973 spot ration was nearly twice 

 that estimated from O2 consumption measure- 

 ments and provides sufficient energy for general 

 metabolism and growth. 



We must consider our larval ration estimates 

 as tentative in light of the high variability in 

 the ration estimates for spot. This variation is 

 due to differences in natural gut content, possibly 

 as a result of differences in food availability 

 on the sampling dates. Extensive sampling 

 under the varied environmental conditions and 

 zooplankton abundances and repeated evacua- 

 tion rate measurements will provide us with 

 more accurate estimates of their daily ration. 



ACKNOWLEDGMENTS 



We wish to express our sincere appreciation 

 to Ronald L. Garner and Jerry D. Watson for 

 their technical assistance during the entire study. 



LITERATURE CITED 



Bajkov, a. D. 



1935. How to estimate the daily food consumption of 

 fish under natural conditions. Trans. Am. Fish. Soc. 

 65:288-289. 

 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. 

 Braum, E. 



1967. The survival of fish larvae with reference to their 

 feeding behaviour and the food supply. In S. D. Gerking 

 (editor), The biological basis of freshwater fish produc- 

 tion, p. 113-131. Blackwell Sci. Publ., Oxford. 



Brooks, J. L., and S..I. Dodson. 



1965. Predation, body size, and composition of plankton. 

 Science (Wash., DC.) 150:28-35. 



Elliott, J. M. 



1972. Rates of gastric evacuation in brown trout, Salmo 

 trutta L. Freshwater Biol. 2:1-18. 

 Heinle, D. R. 



1966. Production of a calanoid copepod, Acartia tonsa 

 in the Patuxent River estuary. Chesapeake Sci. 7:59-74. 



IVLEV, V. S. 



1961. Experimental ecology of the feeding of fishes. 

 (Translated from Russian by D. Scott.) Yale Univ. Press, 

 New Haven, 302 p. 

 June, F. C, and F. T Carlson. 



1971. Food of young Atlantic menhaden, Brevoortia 

 tyrannus, in relation to metamorphosis. Fish. Bull., 

 U.S. 68:493-512. 

 Kjelson, M. a. 



1971. Selective predation by a freshwater planktivore, 

 the threadfin shad, Dorosoma petenense. Ph.D. Thesis, 

 Univ. California, Davis, 123 p. 

 Lewis, R. M., W. F. Hettler, Jr., E. P. H. Wilkens, and 

 G. N. Johnson. 



1970. A channel net for catching larval fishes. Chesa- 

 peake Sci. 11:196-197. 

 May, R. C. 



1970. Feeding larval marine fishes in the laboratory: A 

 review. Calif. Coop. Oceanic Fish. Invest., Rep. 14:76-83. 

 Peters, D. S., and D. E. Hoss. 



1974. A radioisotopic method of measuring food evacua- 

 tion time in fish. Trans. Am. Fish. Soc. 103:626-629. 

 Peters, D. S., and M. A. Kjelson. 



In press. Consumption and utilization of food by various 

 postlarval and juvenile North Carolina estuarine fishes. 

 Proc. 2nd Int. Estuarine Res. Conf., Oct. 15-18, 1973, 

 Myrtle Beach, S.C. 

 Peters, D. S., M. A. Kjelson, and M. T. Boyd. 



1974. The effect of temperature on digestion rate in the 

 pinfish, Lagodon rhomboides; spot, Leostomus xanthurus; 

 and silverside, Menidia menidia. Proc. 26th Annu. Conf. 

 Southeast. Assoc. Game Fish Comm., p. 637-643. 

 Rosenthal, H., and G. Hempel. 



1970. Experimental studies in feeding and food require- 

 ments of herring larvae iClupea harengus L.). In 

 J. H. Steele (editor). Marine food chains, p. 344-364. 

 Univ. Calif Press, Berkeley. 

 Schumann, G. O. 



1965. Some aspects of behavior in clupeid larvae. Calif. 

 Coop. Oceanic Fish. Invest., Rep. 10:71-78. 

 Seaburg, K. G., and J. B. Moyle. 



1964. Feeding habits, digestive rates, and growth of 

 some Minnesota warmwater fishes. Trans. Am. Fish. 

 Soc. 93:269-285. 

 Thayer, G. W., D. E. Hoss, M. A. Kjelson, W. F. Hettler, Jr., 

 AND M. W. LaCroix. 

 1974. Biomass of zooplankton in the Newport River 

 estuary and the influence of postlarval fishes. Chesapeake 

 Sci. 15:9-16. 

 Tyler, A. V. 



1970. Rates of gastric emptying in young cod. J. Fish. 

 Res. Board Can. 27:1177-1189. 

 Werner, R. G. 



1969. Ecology of limnetic bluegill (Lepomis macrochirus) 

 fry in Crane Lake, Indiana. Am. Midi. Nat. 81:164-181. 



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