Norton and MacFarlane. Nutritional dynamics of reproduction in Sebastes flavidus 



303 



Liver 



Month 



Figure 3 



Monthly lipid, protein, glycogen, ash, and water content 

 in liver tissues of yellowtail rockfish, Sebastes flavidus, 

 during one reproductive cycle. Values are means ±SE in 

 grams on a wet weight basis. 



Muscle 



Month 

 Figure 4 



Monthly lipid, protein, glycogen, ash, and water content 

 changes in muscle tissues of yellowtail rockfish, Sebastes 

 flavidus, during one reproductive cycle. Values are means 

 ±SE in grams on a wet weight basis. 



In terms of quantity, protein content and water con- 

 tent were largely responsible for variation in muscle 

 mass (Fig. 4). Protein content in female muscle in- 

 creased 30% from July through November and was 

 significantly greater than that in males (P<0.005). 

 Muscle protein declined significantly in vitellogenic 

 females after November (P<0. 01). Males experienced 

 a gradual decline in muscle protein from July to 

 January. Lipid accounted for less than 5% of muscle 

 mass in both sexes. In the fall, females had greater 

 muscle lipid than males (P<0.05); lipid levels were 

 similar during the other periods. 



Muscle glycogen and ash content in females and 

 males changed little across the reproductive cycle and 

 did not appear to coincide with other component dy- 

 namics. Also, muscle glycogen content was an order 

 of magnitude lower than liver glycogen. 



Nutritional energy dynamics 



By calculating changes in quantities of somatic and 

 gonadal components from the onset of ovarian de- 



velopment to parturition, a mass balance of nutri- 

 tional energy dynamics relative to the female annual 

 reproductive cycle was constructed (Table 2). 



Females lost 94 g of somatic tissue from the start 

 of ovarian development through parturition. Virtu- 

 ally all of this loss was lipid (51 g) and protein (41 g). 

 Females lost 27 g, or about 40% more somatic re- 

 serves than did males. 



Lipid was mobilized from all somatic tissues. From 

 the total lipid loss of 51 g in females, mesenteric fat 

 contributed the most, 21 g, followed by liver and 

 muscle. Mesenteric fat was also the greatest source 

 of lipid loss in males; however, females used approxi- 

 mately 8 g more lipid from mesenteries than did 

 males during the annual cycle. Overall, females lost 

 17 g more lipid from soma than did males, suggest- 

 ing that about two-thirds of lipid depleted from so- 

 matic stores was used for adult maintenance. 



Both females and males lost protein, primarily 

 from muscle, during the time interval of ovarian 

 maturation. Females mobilized 37 g of protein from 

 muscle tissue, which was about 10 grams more than 



