Abstract. — Nutritional dynam- 

 ics of yellowtail rockfish, Sebastes 

 flavidus, were analyzed from the 

 perspective of temporal changes in 

 tissue composition of liver, muscle, 

 mesentery, and gonad to determine 

 aspects specific to female reproduc- 

 tion. Monthly tissue composition 

 data over an annual reproductive 

 cycle indicated that females accu- 

 mulated greater somatic tissue en- 

 ergy reserves than did males dur- 

 ing the summer and fall months. 

 Maternal lipid and protein reserves 

 were depleted in a reciprocal rela- 

 tion with ovarian growth during 

 the winter. The greatest declines of 

 lipid and protein occurred in me- 

 senteries and muscle, respectively. 

 Females lost approximately 40% 

 more somatic tissue than males 

 during the time interval from ova- 

 rian development to parturition. 

 Lipid was the primary energy 

 source, contributing 74% of the en- 

 ergy lost from somatic tissues for 

 female-specific reproductive pur- 

 poses. Two-thirds of lipid depleted 

 from maternal soma was for adult 

 metabolic maintenance. Of the 

 other one-third, 43% was gained in 

 ovary tissue during development, 

 leaving 57% for reproductive meta- 

 bolic costs. Protein increased 220% 

 in ovaries relative to female-spe- 

 cific somatic protein loss, indicat- 

 ing de novo ovarian synthesis. This 

 study is the first report of compre- 

 hensive tissue composition dynam- 

 ics and allocation to reproduction 

 in a viviparous marine teleost. The 

 analytical design used demon- 

 strated the significance of each tis- 

 sue component and the temporal 

 pattern of allocation to reproduc- 

 tive development. 



Nutritional dynamics of 

 reproduction in viviparous 

 yellowtail rockfish, 

 Sebastes flavidus 



Elizabeth C. Norton 

 R. Bruce MacFarlane 



Tiburon Laboratory, Southwest Fisheries Science Center 

 National Marine Fisheries Service, NOAA 

 3 I 50 Paradise Drive, Tiburon, CA 94920 



Manuscript accepted 17 October 1994. 

 Fishery Bulletin 93:299-307 ( 1995). 



Maternal nutritional status and the 

 allocation of nutrients into develop- 

 ing young are important factors con- 

 tributing to reproductive success in 

 fish. Previous investigations have 

 shown that nutritional status can 

 influence fecundity and the vitality 

 of offspring (Anokhina, 1959; Rijns- 

 dorp, 1990; DeMartini, 1991; Kjesbu 

 et al., 1991). By determining the 

 temporal patterns of somatic and 

 gonadal tissue components involved 

 in fish nutritional dynamics, we can 

 improve our understanding of en- 

 ergy and nutritional needs for suc- 

 cessful reproduction. 



Several studies of nutrient dy- 

 namics in fish have used chemical 

 composition analyses of primary 

 body constituents, including lipid, 

 protein, glycogen, water, and ash 

 components, to assess physiological 

 status and the level of available 

 nutritional reserves (Love, 1970; 

 Caulton and Bursell, 1977; Cui and 

 Wootton, 1988). These reserves 

 have been shown to vary by species 

 and interannually in location, quan- 

 tity, and the sequence of allocation 

 into reproductive development 

 (Sargent, 1976; Medford and Mac- 

 kay, 1978; Henderson et al., 1984; 

 MacFarlane et al., 1993). Generally, 

 the principal source of nutritional 

 energy reserve in fish is lipid (Sar- 

 gent, 1976; Sargent et al., 1989). 

 Protein, primarily used in struc- 

 tural development and enzyme syn- 

 thesis, may also be an additional 



source of energy when lipid reserves 

 are depleted ( Mommsen et al. , 1980; 

 Walton and Cowey, 1982). 



Many temperate fish species fol- 

 low a similar seasonal pattern of 

 nutrient dynamics, where energy 

 reserves are accumulated in the 

 summer and depleted during the win- 

 ter reproductive period (Shul'man, 

 1974). The transfer of nutrients 

 from somatic reserves into ovarian 

 growth has been indicated by the 

 reciprocal relationship between the 

 depletion of somatic stores and ova- 

 rian development (MacKinnon, 

 1972; Dawson and Grimm, 1980; 

 Dygert, 1990). While this general 

 pattern has been documented in 

 oviparous species, little data on 

 nutritional dynamics are available 

 for viviparous teleosts (Wourms et 

 al., 1988). For the marine vivipa- 

 rous genus Sebastes, only changes 

 in tissue lipids have been measured 

 in relation to reproduction (Guille- 

 mot et al., 1985; Larson, 1991; Mac- 

 Farlane et al., 1993). 



The yellowtail rockfish, Sebastes 

 flavidus, range from San Diego, 

 California, to Kodiak Island, Alaska 

 (Eschmeyer et al., 1983), and are 

 important both commercially and 

 recreationally (Reilly et al. 1 ; Pacific 



1 Reilly, P. N., D. Wilson-Vandenberg, D. 

 Watters, J. E. Hardwick, and D. Short. 1993. 

 On board sampling of the rockfish and ling- 

 cod commercial passenger fishing vessel in- 

 dustry in northern and central California . 

 May 1987-December 1991. Calif. Dept. Fish 

 Game Admin. Report. 93-4, 242 p. 



299 



