273 



Abstract.— Concentrations of lipids 

 and protein were measured in embryos 

 during gestation in two species of vi- 

 viparous rockfishes off the central Cali- 

 fornia coast. Total lipids and protein de- 

 clined linearly through embryonic 

 maturation in semipelagic yellowtail 

 rockfish, Sebastes flavidus, and pelagic 

 shortbelly rockfish, Sebastes jordani. 

 Energetically, lipids were the predomi- 

 nant source of energy for embryonic 

 development in both species, but lipid 

 and protein catabolism was signifi- 

 cantly greater for yellowtail rockfish. 

 Total lipids, protein, and lipid class 

 composition were measured during 

 embryonic maturation in three popu- 

 lations of shortbelly rockfish, located at 

 Ascension, Pioneer, and Bodega subma- 

 rine canyons, to determine intraspecific 

 variability of nutritional dynamics. 

 Triacylglycerols and polar lipids (mostly 

 phospholipids), the predominant lipid 

 classes in all maturation stages, were 

 depleted through embryonic develop- 

 ment, Steryl or wax esters and choles- 

 terol also declined, but were in much 

 lower concentrations. The goodness-of- 

 fit of linear regressions for protein, to- 

 tal lipid, and lipid classes by stage of 

 embryonic maturation allowed estima- 

 tions of their concentrations at birth, 

 thus providing a measure of nutritional 

 condition, or qualitative reproductive 

 success. Analyses determined that 

 there were significant differences in 

 metabolism and estimated concentra- 

 tions at birth of nutrients between the 

 two species and among the shortbelly 

 rockfish populations, indicating differ- 

 ential potential for survival during 

 early planktonic life stages until favor- 

 able feeding conditions occur Results 

 suggest that the contribution of indi- 

 vidual populations to the diversity of 

 metapopulations or year classes may be 

 influenced by the nutritional condition 

 of larvae at birth. 



Nutritional dynamics during embryonic 

 development in the viviparous genus 

 Sebastes and their application to the 

 assessment of reproductive success 



R. Bruce MacFarlane 



Elizabeth C. Norton 



Tiburon Laboratory, Southwest Fisheries Science Center 



National Marine Fisheries Service, NOAA 



3150 Paradise Drive 



Tiburon, California 94920 



E-mail address (for R, B. MacFarlane) Bruce MacFarlane a noaa gov 



^Manuscript accepted 25 June 1998. 

 Fish. Bull. 97:273-281 1 1999). 



Variability of annual recruitment to 

 marine fish stocks has been attrib- 

 uted to several factors, including 

 the quantity and quality of progeny 

 produced and the influences of en- 

 vironmental conditions on subse- 

 quent survival. Although either fac- 

 tor could be effective alone, at times 

 they may interact. Poor reproduc- 

 tive success, manifested by low fe- 

 cundity or unhealthy progeny, or 

 both, occurring at times of unfavor- 

 able environmental conditions, may 

 lead to particularly weak year 

 classes. There is evidence that fac- 

 tors operating at or near the time 

 of spawning aifect year-class strength 

 in rockfishes (genus Sebastes) along 

 the west coast of North America. 

 Year-class failures of two species of 

 rockfish were found at the extremes 

 of the physical environmental spec- 

 trum off the central coast of Cali- 

 fornia during years of very low or 

 very high upwelling (Ralston and 

 Howard, 1995). The data from that 

 investigation suggested that year- 

 class strength of yellowtail rockfish 

 {Sebastes flavidus) and blue rock- 

 fish (Sebastes mystinus) was related 

 to environmental conditions and 

 was established before the pelagic 

 juvenile stage. Further, annual 

 variation in fecundity does not ap- 

 pear to be great enough to account 

 for the variation seen in fishery re- 

 cruitment of yellowtail rockfish 



( Eldridge and Jarvis, 1995 ) or other 

 species (Shepherd and Gushing, 

 1980). Thus, maternal processes 

 contributing to the health or fitness 

 of embryos or early larvae, in addi- 

 tion to the more often assessed en- 

 vironmental factors, may signifi- 

 cantly influence survival and year- 

 class strength. 



The assessment of reproductive 

 success includes the determination 

 of both the quantity and quality of 

 progeny because year-class strength 

 may be influenced by the health of 

 newborns as well as by the number 

 produced. Although fecundity is of- 

 ten used as a measure of reproduc- 

 tive success and has been related to 

 biological and environmental fac- 

 tors (Blaxter, 1969), less attention 

 has been given to the assessment 

 of the qualitative aspects of repro- 

 ductive success. This is due, in part, 

 to the difficulty of determining 

 which variables or processes are 

 valid measures of egg, embryo, or 

 larval health. Various measures 

 have been proposed, such as egg size 

 (Blaxter and Hempel, 1963), histo- 

 logical criteria (Theilacker, 1978), 

 and biochemical analyses, including 

 nucleic acids (Buckley, 1984), en- 

 zyme activity (Clarke et al., 1992), 

 and biochemical composition (re- 

 viewed by Ferron and Leggett, 

 1994). All have merits; however, fac- 

 tors such as the degree of relation- 



