FISHERY BULLETIN: VOL. 82. NO. 1 



regulated by endocrine levels, and it may be the 

 environmental modulation ofendocrine rhythms that 

 ultimately controls increment periodicity on the 

 otolith (Menaker and Binkley 1981). Endocrine se- 

 cretion often follows a circadian pattern (Simpson 

 1978) and, in mammals at least, is closely linked to 

 the circadian pacemaker itself (Menaker and Binkley 

 1981). Hormones regulate many aspects of meta- 

 bolism and growth, including skeletal calcification 

 (Simpson 1978). Therefore, it seems reasonable to 

 postulate that those factors that entrain and/or mod- 

 erate the circadian rhythm of endocrine secretion will 

 have a subsequent effect on increment deposition in 

 the otolith. 



ACKNOWLEDGMENTS 



Jim McNutt of Ayerst Laboratories kindly donated 

 the antibiotics used in this study. I appreciate the 

 assistance and technical innovation of Doug Begle in 

 the field and laboratory. John D. Neilson and Nor- 

 man J. Wilimovsky provided many helpful comments 

 on an earlier draft of the manuscript. This study was 

 supported by a grant from the Natural Sciences and 

 Engineering Research Council of Canada to Norman 

 J. Wilimovsky. 



LITERATURE CITED 



Arora, H. L 



1948. Observations on the habits and early life history of the 

 batrachoid fish Porichthys notatus Girard. Copeia 

 1948:89-93. 

 Brothers, E. B. 



1981. What can otolith microstructure tell us about daily and 

 subdaily events in the early life history of fish? Rapp. P.- 

 V. Reun. Cons. Int. Explor. Mer 178:393-394. 

 Brothers, E. B., C. P. Mathews, and R. Lasker. 



1976. Daily growth increments in otoliths from larval and 

 adult fishes. Fish. Bull., U.S. 74:1-8. 

 Brothers, E. B., and W. N. McFarland. 



1981. Correlations between otolith microstructure, growth, 

 and life history transitions in newly recruited French grunts 

 \Haemulon flavoUneatum (Desmarest), Haemulidae]. Rapp. 

 P-V Reun. Cons. Int. Explor. Mer 178:369-374. 



Campana, S. E. 



1983. Feeding periodicity and the production of daily growth 

 increments in otoliths of steelhead trout (Salmo gairdneri) 

 and starry flounder (Platichthys stellatus). Can. J. Zool. 

 61:1591-1597. 



Campana, S. E., and J. D. Neilson. 



1982. Daily growth increments in otoliths of starry flounder 

 {Platichthys stellatus) and the influence of some environ- 

 mental variables in their production. Can. J. Fish. Aquat. 

 Sci. 39:937-942. 



Davis, F. C. 



1981. Ontogeny of circadian rhythms. In J. Aschoff (editor). 

 Handbook of behavioral neurobiology, Vol. 4, p. 257- 

 274. Plenum Press, N.Y. 



ENRIGHT, J. T. 



1981. Methodology. In J. Aschoff (editorl. Handbook of be- 

 havioral neurobiology. Vol. 4, p. 11-19. Plenum Press, N.Y. 



Gibson, R. N., J. H. S. Blaxter, and S. J. de Groot. 



1978. Developmental changes in the activity rhythms of the 

 plaice (Pleuronectes platessa L.). In J. E. Thorpe (editor). 

 Rhythmic activity of fishes, p. 169-186. Acad. Press, 

 N.Y. 



Marshall, S. L., and S. S. Parker. 



1982. Pattern identification in the microstructure of sockeye 

 salmon {Oncorhynchus nerka) otoliths. Can. J. Fish. 

 Aquat. Sci. 39:542-547. 



Matty, A. J. 



1978. Pineal and some pituitary hormone rhythms in fish. In 

 J. E. Thorpe (editor), Rhythmic activity of fishes, p. 21- 

 30. Acad. Press, N.Y. 

 Menaker, M., and S. Binkley. 



1981. Neural and endocrine control of circadian rhythms in 

 the vertebrates. In J. Aschoff (editor). Handbook of 

 behavioral neurobiology, Vol. 4, p. 243-256. Plenum 

 Press, N.Y. 

 Methot, R. D„ Jr. 



1981. Spatial covariation of daily growth rates of larval 



northern anchovy, Engraulis mordax, and northern 



lampfish, Stenobrachius leucopsarus. Rapp. P.-V. Reun. 



Cons. Int. Explor. Mer 178:424-431. 



Mugiya, Y., N. Watabe, J. Yamada, J. M. Dean, D. G. 



Dunkelberger, and M. Shimuzu. 



1981. Diurnal rhythm in otolith formation in the gold fish, 

 Carassius auratus. Comp. Biochem. Physiol. 68A:659- 

 662. 



Neilson, J. D., and G. H. Geen. 



1982. Otoliths of chinook salmon (Oncorhynchus tsha- 

 wytscha): daily growth increments and factors influencing 

 their production. Can. J. Fish. Aquat. Sci. 39:1340-1347. 



PANNELLA, G. 



1971. Fish otoliths: daily growth layers and periodical pat- 

 terns. Science (Wash., D.C.) 173:1124-1127. 



1980. Growth patterns in fish sagittae. In D. C. Rhoads and 

 R. A. Lutz (editors). Skeletal growth of aquatic organisms: 

 Biological records of environmental change, p. 519- 

 560. Plenum Press, N.Y. 



Ralston, S. 



1976. Age determination of a tropical reef butterflyfish utiliz- 

 ing daily growth rings of otoliths. Fish. Bull., U.S. 74:990- 

 994. 

 Sacher, G. A., and P. H. Duffy. 



1978. Age changes in rhythms of energy metabolism, activity 

 and body temperature in Mus and Peromyscus. In H. V. 

 Samis, Jr., and S. Capobianco (editors). Aging and biologi- 

 cal rhythms, p. 105-124. Plenum Press, N.Y. 

 Simpson, T. H. 



1978. An interpretation of some endocrine rhythms in 

 fish. //; J. E. Thorpe (editor). Rhythmic activity of fishes, 

 p. 55-68. Acad. Press, N.Y. 

 Struhsaker, P., and J. H. Uchiyama. 



1976. Age and growth of the nehu, Stolephorus purpureus 

 (Pisces: Engraulidae), from the Hawaiian islands as 

 indicated by daily growth increments of sagittae. Fish. 

 Bull., U.S. 74:9-17. 



Tanaka, K., Y. Mugiya, and J. Yamada. 



198 1. Effects of photoperiod and feeding on daily growth pat- 

 terns in otoliths of juvenile Tilapia nilotica. Fish. Bull., 

 U.S. 79:459-466. 



Taubert, B. D., and D. W. Coble. 



1977. Daily rings in otoliths of three species of Lepomis and 



176 



