Abstract. — We investigated in- 

 crement formation in sagittae of At- 

 lantic menhaden Brevoortia. tyrannus 

 in laboratory experiments, and found 

 that the age of individual larvae can 

 be estimated within + 3 days over 

 the first month of life using counts 

 of growth increments. Sagittae were 

 first obsei"ved dmnng embryonic devel- 

 opment. The first prominent growth 

 increment was formed at first feed- 

 ing, and the frequency of increment 

 formation of fed and starved larvae 

 ranged from 0.86 to 0.98 increments 

 per day thereafter. Starvation did not 

 appear to systematically alter the 

 periodicity of increment formation 

 from one increment per day, although 

 it consistently modified the width of 

 growth increments among different 

 age groups of lai^vae. Microstructural 

 growth pattems in sagittae responded 

 rapidly (days) to changes in feeding: 

 larvae starved for 1-3 days formed 

 narrow, poorly-defined increments 

 compared with fed larvae that formed 

 wide, well-defined increments. Stan- 

 dard length and estimated diy weight 

 of larvae were related to sagittal 

 radius by asymptotic and logistic func- 

 tions, respectively. Sagittal radius of 

 larvae was related to days after first 

 feeding by a logistic function. Our re- 

 sults for Atlantic menhaden confirm 

 the potential of otoliths in provid- 

 ing information about age, stressful 

 events, and growth history of in- 

 dividual fish larvae. 



Effects of Starvation on 

 the Frequency of Formation 

 and WidtPi of Growth Increments 

 \n Sagittae of Laboratory-Reared 

 Atlantic Menhaden Brevoortia 

 tyrannus Larvae 



Gary L. Maillet 



Department of Marine, Earth, and Atmospheric Sciences 



North Carolina State University, Box 8208, Raleigh, North Carolina 27695-8208 



Present address Department of Biology, McGill University 



1205 Ave Docteur Penfield. Montreal. Quebec, Canada H3A IBl 



David A/I. Checkley, Jr. 



Department of Marine, Earth, and Atmospheric Sciences 



North Carolina State University. Box 8208, Raleigh, North Carolina 27695-8208 



Manust'ript accepted 20 September 1989, 

 Fi.shery Bulletin, U.S, 88:15,5-165, 



Rates of growth and survival of 

 young fish are hypothesized to affect 

 the abundance of the incoming year- 

 class (Lasker 1985, Rothschild 1986). 

 Both biotic (e,g., prey resources) and 

 abiotic (e.g., water temperature) fac- 

 tors have a direct effect on the 

 growth and survival of freshwater 

 and marine fish larvae. Microstruc- 

 tural growth patterns in otoliths of 

 teleost fish may provide a record of 

 environmental and physiological con- 

 dition throughout the larval and juve- 

 nile stages and hence important in- 

 formation about processes regulating 

 recruitment in fish (Pannella 1980, 

 Houde 1987, Rice et al. 1987). 



The examination of microstruc- 

 tural growth patterns in otoliths for 

 making inferences about the ecology 

 of young fishes has become a popular 

 technique since Pannella (1971) pos- 

 tulated that annuli (yearly growth 

 zones) consisted of growth incre- 

 ments formed on a daily basis. Subse- 

 quently, microstructtiral growth pat- 

 terns have been used to estimate age 

 and growth histories of fish (Methot 

 and Kramer 1979, Penney and Evans 

 1985), infer the temperattire chronol- 

 ogy of larval and juvenile life stages 



(Radtke 1984, Gauldie et al. 1986), de- 

 tect life history transitions (Brothers 

 and McFarland 1981, Campana 1984a), 

 and investigate patterns of recruit- 

 ment and mortality (Crecco et al. 



1983, Essig and Cole 1986) and stock 

 identification (Mulligan et al. 1987). 



Age validation studies of lar-val and 

 juvenile fishes have shown that micro- 

 structural characteristics are species- 

 specific and may be influenced by 

 nutrition and/or environmental vari- 

 ables (Campana and Neilson 1985, 

 Rice et al. 1985, Jones 1986). Fish lar- 

 vae subjected to periods of stress 

 (e.g., starvation) or cyclic environ- 

 mental variables (e.g., diel fluctua- 

 tions in water temperature) may have 

 their increment deposition disrupted, 

 resulting in apparent nondaily forma- 

 tion (Taubert and Coble 1977, Jones 



1984, Neilson and Geen 1985). These 

 results suggest that validation stud- 

 ies are necessary for a species before 

 analysis of otolith microstructure can 

 be used to age individuals in nature. 

 Substantial errors may be incorpor- 

 ated into the analysis if daily incre- 

 ment formation is assumed but non- 

 daily deposition occurs (Campana and 

 Neilson 1985). 



155 



