P.O. Box 5667 



St. John's, Newfoundland AlC 5X1, Canada 



NICOS/Biology Department 



Memorial University of Newfoundland 



St. John's, Newfoundland A IB 3X9, Canada 



Fisheries Research Branch 



Department of Fisheries and Oceans 



P.O. Box 5667 



St. John's, Newfoundland, AlC 5X1, Canada 



R. G. Hooper 



G. P. Ennis 



FEEDING, DIET, AND REPEAT SPAWNING 



OF BLUEBACK HERRING, ALOSA 



AESTIVALIS, FROM THE CHOWAN RIVER, 



NORTH CAROLINA 



Current knowledge of the frequency of feeding 

 among spawning blueback herring, Alosa aestivalis 

 Mitchill, is limited. Other aspects of the blueback 

 herring's life history have been more extensively 

 studied: feeding of juveniles (Davis and Cheek 1966; 

 Nichols 1966; Burbidge 1974; Domermuth and Reed 

 1980; Crecco and Blake 1983), distribution at sea 

 (Hildebrand 1963; Holland and Yelverton 1973^; 

 Neves 1981), and spawning range (Bigelow and 

 Schroeder 1953; Hildebrand 1963; Scott and Cross- 

 man 1973). However, determination of the occur- 

 rence of feeding by adults in freshwater has received 

 little attention despite the fact that spawning 

 bluebacks are common in rivers from southern New 

 England (Bigelow and Schroeder 1953) to the St. 

 Johns River, FL (Hildebrand 1963). Throughout this 

 extensive range only Frankensteen (1976) has 

 studied feeding among adult bluebacks in fresh- 

 water. Furthermore, no attempt has been made to 

 correlate feeding with length, weight, and sex of in- 

 dividual fish, distance upstream, or the number of 

 seasons a blueback has spawned. 



The objective of this study is to enhance our 

 knowledge of the freshwater feeding of blueback 

 herring. In this paper I describe the occurrence of 

 feeding, diet, and percentage of repeat spawning 

 among adults collected in the Chowan River, NC. I 



also examined, by multiple regression analysis, the 

 relation between feeding activity in freshwater and 

 length, weight, sex, the number of repeat spawnings, 

 and the distance travelled upstream. 



Materials and Methods 

 Collection of Data 



Bluebacks were collected at two sites in the lower 

 Chowan River system during April 1980 and 1981. 

 Williams' Fishery, where five collections were made 

 in 1980, is located on the lower Meherrin River near 

 its junction with the Chowan River, 90 km upstream 

 from the Chowan River's mouth. Rocky Hock Creek, 

 where bluebacks were sampled twice in 1980 and 

 once in 1981, is roughly 20 km from the mouth of 

 the Chowan River. Bluebacks at Williams' Fishery 

 were still migrating upstream while those at Rocky 

 Hock Creek, a known spawning ground,^ were 

 preparing to spawn. 



Bluebacks were caught in chicken-wire dip nets 

 and fixed gill nets with 58 mm stretched mesh at 

 Rocky Hock Creek. A drift gill net of similar 

 mesh size and a haul seine were used at Williams' 

 Fishery. None of the fish collected had spawned 

 yet. 



Bluebacks were measured, weighed, and sexed, 

 and scales were removed for aging. The foregut and 

 midgut regions of the stomach anterior to the pyloric 

 caeca were removed and placed in 15% Formalin^ 

 within 10-15 min of capture 



Stomach contents were examined in the laboratory 

 under a dissecting scopa First, fullness of the 

 foregut and midgut, which are separate sections, was 

 estimated visually following Hynes (1950) and 

 Yoshiyama (1980). Five levels of fullness were 

 used: half full (1/2), full (1), and distended with food 

 (2) (as in Yoshiyama 1980), plus one quarter full (1/4), 

 and empty or with traces of food (0). Contents of 

 each section were then placed in a petri dish, iden- 

 tified, and counted. Also, the presence or absence 

 of prey items was noted. 



Scales were viewed at 50 x through an EPO LP-2 

 Profile Projector and marks were interpreted follow- 

 ing Marcy (1969). 



iRolland, B. F., Jr., and G. F. Yelverton. 1973. Offshore 

 anadromous fish exploratory fishing program. Completion report, 

 Project AFC-5, 123 p. North Carolina Department of Natural and 

 Economic Resources, Division of Commercial and Sports Fisheries, 

 Raleigh, NC 27611. 



^S. Winslow, North Carolina Division of Marine Fisheries, 

 Elizabeth City, NC 27909, pers. commun. February 1980. S. 

 Winslow had determined the previous year (1979) that blueback 

 herring collected at this site on Rocky Hock Creek were spawn- 

 ing. Also, a dam upstream prevented blueback herring from moving 

 any further than 150 m above my collection sita 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



FISHERY BULLETIN: VOL. 83, NO. 4, 1985. 



711 



