FISHERY BULLETIN: VOL. 87, NO. 2, 1989 



NL. Six days after EYS, fed larvae of both species 

 were 4.1-4.2 mm NL (sea bass 58 ^ig, anchovies 19 

 Hg). After 168 hours past first feeding, sea bass 

 weighed 49 ng and anchovies 22 ^ig. Length of unfed 

 larvae reached a maximum between EP and EYS 

 (anchovies, 3.4 mm; sea bass, 3.2 mm) and a mini- 

 mum between EYS and S (anchovies, 3.0 mm; sea 

 bass, 2.9 mm). 



Body Composition 



Similar trends in total carbon and total nitrogen 

 content occurred for unfed and fed larvae of both 

 species (Table 2). Percent nitrogen was relatively 

 constant. Percent carbon and C/N decreased be- 

 tween hatching and yolk exhaustion, and then were 

 relatively constant. Although data are limited, there 

 was an apparent decrease in total lipid content of 

 black sea bass throughout development. Values for 

 the five samples were 1 h eggs, 14.5%; 4 h eggs, 

 15.6%; 217 h unfed larvae, 12.9%; 186 h fed lar- 

 vae, 12.1%; 298 h fed larvae, 10.4%. Sea bass eggs 

 and larvae contained about 50% more ash than 

 anchovies (Table 3). Bomb calorimetry energy 

 values were similar. Mean values in calories per 

 gram for eggs were anchovies, 5,477 (SD 103, n = 

 5), ash-free 5,833; sea bass, 5,315 (SD 220, n = 

 5), ash-free 5,841. Representative calculations of 



Table 2.— Carbon and nitrogen content of bay anchovy and black 

 sea bass eggs and larvae during growth and starvation. 



caloric content for energy budgets are shown in 

 Table 4. 



Oxygen Consumption 



The relationship between age and oxygen con- 

 sumption depended on species, developmental 

 phase, and nutritional status (Figs. 3, 4). In bay an- 

 chovies, oxygen uptake increased continuously. In 

 black sea bass, uptake rose until hatching, dropped, 

 then rose again. Uptake decreased for unfed larvae. 



Feeding Behavior 



Black sea bass capture success was consistently 

 higher than that of bay anchovies (Fig. 5). Anchovy 

 capture success increased from 54% on feeding 

 day 1 to 77% on feeding day 8. Sea bass capture 

 success was 70% on feeding day 1, and during feed- 

 ing days 2-8 remained relatively constant at 

 86-94%. 



Sea bass feeding incidence was higher than that 

 of anchovies during the first four feeding days (Fig. 

 5). Anchovy feeding incidence gradually increased 

 from 40% on feeding day 1 to 100% on feeding day 

 8. Sea bass feeding incidence varied at 85-97% dur- 

 ing the first five feeding days and then remained 

 at 100% for feeding days 6-8. 



Sea bass larvae had a higher flexing rate but lower 

 strike per flex rate than anchovies. In anchovies, 

 mean number of flexes per hour was 9 at first feed- 



Table 3.— Ash content of various stages of bay 

 anchovy and black sea bass. 



'Values from calorimetry tor comparison only, not 

 used in energy budget calculations 



284 



