Egg Size, Female Effects, and the Correlations Between 



Early Life History Traits of Capelin, Mallotus villosus: 



An Appraisal at the Individual Level^ 



R. Christopher Chambers, William C. Leggett, and Joseph A. Brown 



ABSTRACT: The authors examined the within- 

 individual correlations between egg quality (quan- 

 tified by yolk volume) and early life history traits in 

 capelin, Mallotus rillosus. The commonly reported 

 generalization — large eggs produce large larvae 

 that subsist longer on endogenous energy re- 

 serves — was not supported by our analysis. Post- 

 hatching lifespan of unfed lar\ae did not vary with 

 initial egg yolk volume, yolk-sac volume at hatch- 

 ing, or size at hatching. The only correlate of post- 

 hatching lifespan was a direct relationship with oil 

 globule volume at hatching. Size and age at hatch- 

 ing covaried directly, but hatching later exacted a 

 cost on yolk reserves. Significant female influences 

 on these early life history traits of offspring were 

 found. Initial egg yolk volume and oil globule vol- 

 ume at hatching contributed most to the rejection 

 of the null hypothesis of no female effect. None of 

 the early life history traits examined was correlated 

 with female size, but female condition and lipid 

 indices were directly correlated with average initial 

 yolk volume. 



Most individuals in marine fish populations die 

 before feeding begins (Hewitt et al. 1985; Ware 

 and Lambert 1985; McGurk 1986; Taggart and 

 Leggett 1987a). Central to much of Reubin 

 Lasker's work was the role of timing in survival 

 during these early life stages. This was explicit 

 in his early papers on temperature-dependent 

 developmental rates (Lasker 1962, 1964; Zweifel 

 and Lasker 1976) and became an implicit part of 

 his "stable oceans hypothesis" (Lasker 1975, 



'Contributions to the programs of GIROQ (Groupe inter- 

 universitaire de recherches oeeanographiques de Quebec) 

 and tlie Huntsman Marine Science Centre. 



R. Christopher Chambers, William C. Leggett, Depart- 

 ment of Biology. McGill University, 1205 Ave. Dr. Peniield, 

 Montreal, Quebec, Canada H3A IBl. 



and Marine Sciences Research Laboratory, Memorial Uni- 

 versity of Newfoundland, St. John's, Newfoundland, Canada 

 AlC 5S7. 



Joseph A. Brown, Department of Biology, McGill Univer- 

 sity, 120.5 Ave. Dr. Penfield, Montreal, Quebec, Canada H3A 

 IBl; present address: Marine Sciences Research Labora- 

 tory, Memorial University of Newfoundland, St. John's, 

 Newfoundland, Canada AlC 5S7. 



Manuscript Accepted May 1989. 

 Fishery Bulletin. U.S. 87; 515-523. 



1981, 1985), which postulates that coincidence in 

 the timing of physical oceanogi'aphic conditions 

 favoring food production and the timing of first 

 feeding in fish larvae is critical to larval survival. 

 Peterman and Bradford (1987) recently evalu- 

 ated interannual variability in both the fre- 

 quency of turbulence-generating winds and the 

 survival of northern anchovy, Engraniis 

 ■mordax, larvae and found an inverse relation- 

 ship between these two events. 



Temporal matching of resources and consum- 

 ers is one of degi'ee as timing of early life history 

 (ELH) events varies even under constant condi- 

 tions (Chambers and Leggett 1987, 1989; Cham- 

 bers et al. 1988). Knowledge of the within-popu- 

 lation variation in ELH traits is, therefore, 

 crucial for estimating the number of larvae that 

 establish feeding, and thus retain the potential 

 for recruitment to the fishery. To Lasker's 

 credit, his temperature-dependent development 

 experiments in sardines, Sardinops sagax, were 

 conducted on individual embryos isolated in incu- 

 bation chambers in order "to assess their individ- 

 ual variability of development and growth" 

 (Lasker 1964, p. 399). While variability in hatch- 

 ing age within and across temperatures is appar- 

 ent from Lasker's plot of age at hatching of 

 individual sardines versus temperature, the po- 

 tential relevance of this variabihty to survival 

 was not discussed further. 



Variable provisioning of energy reserves to 

 embryos is one of several mechanisms that could 

 generate variability in size at hatching, in size 

 and age at first feeding, in ability to withstand 

 starvation, and, consequently, in survival to and 

 during the critical switch from endogenous to 

 exogenous nutrition. It is often reported that 

 larger eggs produce larger larvae that subsist 

 longer without food (e.g., Blaxter and Hempel 

 1963). Although this has become doctrine in re- 

 views of marine fish early hfe histories (Blaxter 

 1969, 1988; Hempel 1979; Hunter 1981; Roths- 

 child 1986), at least one of three caveats applies 

 to work that has led to this generahzation. 1) 

 Eggs were grouped either by size (e.g., small vs. 



515 



