278 



Fishery Bulletin 97(2), 1999 



in reproductive strategy. Yellowtail rockfish 

 produce about 700,000 eggs/female (Eldridge 

 and Jarvis, 1995) whereas shortbelly rock- 

 fish fecundity is about 16,500 eggs/female 

 (EldridgeM. Also, yellowtail rockfish eggs and 

 hatched larvae are considerably smaller than 

 those of shortbelly rockfish (Matarese et al., 

 1989; Eldridge^). Greater energy consump- 

 tion for production of yellowtail rockfish lar- 

 vae may be a consequence of greater energy 

 required for the synthesis of more larvae, 

 their organelles, and subsequent cellular dif- 

 ferentiation. 



The relative importance of lipids and pro- 

 tein as sources of nutrition during embryonic 

 and larval development in oviparous fishes 

 has been presented in other reports. In the 

 marine teleost, Spai'us aurata, free amino 

 acids were the main source of energy during 

 the relatively short embryonic period (ca. 51- 

 58 h postfertilization) whereas lipids and 

 protein did not supply substantial energy 

 until after hatching (Ronnestadet al., 1994). 

 Winter flounder iPseiidopleuronectes ameri- 

 canus), by contrast, used small amounts of carbohy- 

 drate first, then protein until hatching (Cetta and 

 Capuzzo, 1982). Lipid depletion did not occur until 

 after hatching. Protein concentrations were stable, 

 whereas lipids were catabolized in eggs and newly 

 hatched larvae of Senegal sole (Solea senegalensis) 

 (Mourente and Vasquez, 1996). According to these 

 researchers, this pattern of lipid metabolism is char- 

 acteristic of temperate marine fishes with eggs con- 

 taining oil globules, high lipid content, and short de- 

 velopmental periods. The rockfish species in the 

 present study are temperate marine teleosts that 

 contain oil globules and high lipid levels. However, 

 they are viviparous and have relatively lengthy de- 

 velopment, yet catabolize both protein and lipids for 

 energy-consuming processes, thus emphasizing the 

 great variability and lack of generality in the sources 

 and patterns of nutrient use for embryonic and lar- 

 val development in fishes. 



Total lipid concentrations can be considered a mea- 

 sure of physiological condition of larvae (Ferron and 

 Leggett, 1994), and thus an indicator of potential 

 reproductive success, but not all types, or classes, of 

 lipids are equivalent with respect to metabolic avail- 

 ability or in vivo energy yield. Therefore, fraction- 

 ation of total lipids into classes representative of 

 energy-yielding and structural functions provides 



Sebastes jordani 



Embryo maturation stage 



Figure 3 



Changes in lipid classes during embryonic maturation in shortbelly 

 rockfish, Sebastes jordani. Data (means ± SEl are from populations 

 at all three submarine canyons. Number of females assayed for each 

 EMS is same as in Figure 2. See Table 1 for description of EMS. 



' Eldrige. M. B. 1997. 

 ies Science Center. 

 94720. Unpubl. data. 



Tiburon Laboratory, Southwest Fisher- 

 3150 Paradise Drive, Tiburon. CA 



greater knowledge of the amount of energy available 

 to sustain growth and survival once the larvae are 

 released into the environment. 



Total lipid from shortbelly rockfish embryos was 

 fractionated into five lipid classes: steryl/wax esters 

 (esters), triacylglycerols (TAGs), nonesterified fatty 

 acids (NEFAs), cholesterol (CH), and polar lipids 

 (PLs). The separations were not performed on yel- 

 lowtail rockfish embryos owing to loss of samples 

 before chromatographic analysis. 



Triacylglycerols (TAGs) and PLs were the predomi- 

 nant lipids in all stages of embryonic maturation and 

 showed the greatest declines during development 

 (Fig. 3). Cholesterol (CH) and esters were found in 

 much lower concentrations and declined slightly, but 

 significantly, during embryogenesis (Fig. 3; Table 2). 

 Nonesterified fatty acids (NEFAs) were found in very 

 low concentrations and did not vary significantly by 

 stage of maturation (Table 2). 



The depletion of TAG and PL from fertilization to 

 birth indicates the oxidation of these lipid classes 

 for energy-requiring embryogenic processes. The use 

 of TAG for energy storage and fuel during embry- 

 onic and larval development is well known in fishes 

 (Boulekbache, 1981; Vetter et al., 1983; Tocher and 

 Sargent, 1984; Eraser, 1989). Polar lipids, consist- 

 ing mainly of phospholipids, such as phosphatidyl- 

 choline and phosphatidylethanolamine, although 

 used as fundamental structural units of all biologi- 

 cal membranes, have been shown to be a significant 

 source of energy also for embryonic development in 



