ENERGY UTILIZATION IN BAY ANCHOVY, ANCHOA MITCHILLI, AND 



BLACK SEA BASS, CENTROPRISTIS STRIATA STRIATA, 



EGGS AND LARVAE' 



John W. Tucker, Jr.^ 



ABSTRACT 



Bay anchovy, Anchoa mitchilli. and black sea bass, Centropristis striata striata, both produce abun- 

 dant, small, planktonic eggs and larvae, but these appear to have contrasting nutritional strategies. 

 Developmental changes and energy utilization in eggs, unfed larvae, and fed larvae of the two species 

 suggest that black sea bass are better able to resist fluctuations in food availability (survive and grow 

 at lower prey densities). Black sea bass have more time to find food and develop feeding skills— 47 hours 

 between first feeding and yolk exhaustion vs. 8 hours for bay anchovies. Sea bass feed more efficiently 

 than anchovies. Over the first 96 hours after first feeding, capture success averaged 85% for sea bass 

 and 60% for anchovies. Gross growth efficiency of sea bass (13%) was more than twice that of anchovies 

 (5%). Sea bass may also be more resistant to starvation because their yolk lasts longer (180 hours vs. 

 80 hours after hatching) and because, during starvation, their metabolism is lower and they lose body 

 calories at a lower rate. 



An important determinant of survival of larval 

 fishes is their ability to fulfill nutritional require- 

 ments after yolk energy is exhausted. The manner 

 in which energy is used by fish eggs and larvae may 

 indicate adaptability of early stages relative to food 

 composition or abundance. Differences in energy 

 utilization among species might result from different 

 feeding strategies or from adaptation to different 

 feeding conditions (Hunter 1980). 



The bay anchovy, Anchoa mitchilli, a clupeiform 

 planktivore, is a major food item for predaceous 

 fishes along the U.S. Gulf and Atlantic coasts. 

 Adults are pelagic and live in shallow coastal waters 

 from the Gulf of Maine to Yucatan, Mexico (Hilde- 

 brand 1963). In North Carolina, spawning by large 

 schools occurs just after sunset in estuaries and 

 coastal waters from late April to early September 

 and peaks during late June to early August (Kuntz 

 1914; Hildebrand and Cable 1930; pers. obs.). Eggs 

 (which lack oil globules) and larvae are planktonic 

 and occur in estuaries and bays and just offshore. 

 Spawning might occur over a wide temperature 

 range (Dovel 1971), but larval growth is best in the 

 mid to high twenties (Houde 1974). Early juveniles 

 are abundant in brackish water and also enter fresh 

 water. 



'Contribution 673, Harbor Branch Oceanographic Institution, 

 Fort Pierce, FL. 



^Harbor Branch Oceanographic Institution, 5600 Old Dixie 

 Highway, Fort Pierce, FL 34946. 



Manuscript accepted November 1988. 

 Fishery Bulletin, U.S. 78:279-293. 



The black sea bass, Centropristis striata striata, 

 a perciform piscivore generally found offshore, sup- 

 ports important commercial and sport fisheries 

 along the U.S. Atlantic coast. It is distributed over 

 the continental shelf and in bays from Cape Cod, 

 MA to Cape Canaveral, FL and occasionally to the 

 Gulf of Maine or Florida Keys (Miller 1959; Musick 

 and Mercer 1977). Adults are demersal, and south 

 of Cape Hatteras they are found on rough bottom 

 over the inner shelf. Spawning takes place over the 

 inner shelf, mostly in spring or summer, depending 

 on latitude (Musick and Mercer 1977). Off North 

 Carolina, peak spawning is from March to early 

 June. Eggs (with a single oil globule) and larvae are 

 planktonic and occur in shelf waters of 15-51 m 

 depth (Kendall 1972). Juveniles are often found in 

 high salinity estuaries and bays but move into deep- 

 er water as they grow. 



Several aspects of the feeding ecology of bay an- 

 chovy larvae have been investigated, but little is 

 known about black sea bass larvae. Houde and 

 Schekter (1981, 1983) compared growth and ener- 

 getics of bay anchovy; sea bream, Archosargus 

 rhomboidalis; and lined sole, Achirtis lineatus, lar- 

 vae. No studies of black sea bass larval ecology have 

 been published, but the southern sea bass, C. striata 

 melana, has been reared under experimental mari- 

 culture conditions in Florida (Hoff 1970; Roberts et 

 al. 1976; Harpster et al. 1977). 



This paper presents information on developmen- 

 tal events and energy utilization for bay anchovy and 



279 



