MERRI>fER: REPRODUCTIVE BIOLOGY OF THE WEAKFISH 



In Delaware Bay a female weakfish, 190 mm SL, 

 contained a total of 267,500 eggs and would re- 

 lease approximately 52,000 eggs at one spawning 

 (Daiber 1954). My estimates of fecundity for 

 females of a similar size are equivalent to the 

 total egg production figure for Delaware Bay. 

 Fecundity increases by approximately 106,000 

 eggs for each 100 g of body weight for weakfish in 

 Delaware Bay, while my data indicate an in- 

 crease of 127,900 eggs per 100 g of body weight. 



The variation in fecundity per age-group is best 

 explained by the size range present in the sam- 

 ples of each age-group. Regression analysis 

 showed a significant relationship between fecun- 

 dity and fish length (coefficient of determination 

 = r^ = 0.85) and between fecundity and fish 

 weight (r^ = 0.88). The average range of standard 

 length for all females in age-groups to IV was 

 57 mm. High variability in fecundity estimates 

 for age-groups is expected due to the range in fish 

 size and variation in gonad size among fish of the 

 same size (Bagenal 1967). 



It is highly unlikely that weakfish experienced 

 a synchronous failure or severe depression of em- 

 bryonic or larval survival in all spawning areas. 

 Harmic (1958) analyzed the early life history of 

 weakfish in Delaware Bay. Fertilized eggs are 

 pelagic and measure from 0.87 to 0.99 mm in 

 diameter. Weakfish larvae emerge after about 40 

 h at water temperatures of 68° to 70° F and aver- 

 age 1.8 mm SL. Soon after hatching, the demersal 

 larvae disperse into the nursery areas. Through- 

 out the coastal waters from North Carolina to at 

 least New York, anomalous water conditions 

 (such as rapid changes in salinity, temperature, 

 or dissolved oxygen) may occur in small areas due 

 to local weather phenomena or industrial- 

 domestic development. Hurricanes, however, may 

 affect the entire eastern seaboard (tropical storm 

 Agnes — 1972) or portions of it (Hurricane 

 Camille — 1969) with the greatest impact occur- 

 ring in the estuarine areas (i.e., weakfish nur- 

 sery). The extended spawning season of weakfish 

 would tend to minimize any effect of a short-term 

 calamity upon a local population. 



Tolerance of weakfish eggs and larvae to tem- 

 perature, salinity, dissolved oxygen, etc., remains 

 poorly known. According to data compiled by 

 Harmic (1958), natural fluctuations in the es- 

 tuary approach the ranges that are detrimental 

 to weakfish survival. For Delaware Bay and pre- 

 sumably throughout its range, the variation in 

 water parameters due to natural phenomena 



alone may largely explain fluctuations in the 

 weakfish population abundance and year class 

 strength. 



LITERATURE CITED 



Bagenal, T. B. 



1967. A short review of fish fecundity. In S. D. Gerking 

 (editor), The biological basis of freshwater fish produc- 

 tion, p. 89-111. John Wiley and Sons Inc., N.Y. 

 BIGELOW, H. B., AND W. C. SCHROEDER. 



1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. Serv., 

 Fish. Bull. 53, 577 p. 



BRowTj, J., AND E. McCoy. 



1969. A review of the North Carolina scrap fishery. N.C. 

 Dep. Conserv. Dev., Div., Conuner. Sport Fish., Mimeo. 

 Rep., 13 p. 

 Daiber, F. C. 



1954. Fisheries research program. Mar. Lab. Dep. Biol. 

 Sci., Univ. Del. Biennial Rep. 1953 and 1954. Publ. 

 2:50-64. 



fahy, W. E. 



1965a. Report of trash-fish study in North Carolina in 1962. 



Div. Commer. Fish., N.C. Dep. Conserv. Dev., Spec. Sci. 



Rep. 5, Mimeo., 20 p. 

 1965b. Report of trash-fish study in North Carolina in 1964. 



Div. Commer. Fish., N.C. Dep. Conserv. Dev., Spec. Sci. 



Rep. 7, Mimeo., 13 p. 

 Harmic, J. L. 



1958. Some aspects of the development and ecology of 

 the pelagic phase of the gray squeteague, Cynoscion 

 regalis (Bloch and Schneider), in the Delaware estuary. 

 Thesis, Univ. Delaware, Newark, 84 p. 

 HIGGINS, E., AND J. C. PEARSON. 



1928. Examination of the summer fisheries of Pamlico and 

 Core sounds, N.C, with special reference to the de- 

 struction of undersized fish and the protection of the 

 gray trout Cynoscion regalis (Bloch and Schneider). 

 Rep. U.S. Comm. Fish., 1927 append. 2:29-65. 

 HILDEBRAND, S. F., AND L. E. CABLE. 



1934. Reproduction and development of whitings or king- 

 fishes, drums, spot, croaker, and weakfishes or sea- 

 trouts, family Sciaenidae, of the Atlantic Coast of the 

 United States. U.S. Bur. Fish., Bull. 48:41-117. 

 HILDEBRAND, S. F., AND W. C. SCHROEDER. 



1927. Fishes of Chesapeake Bay. U.S. Bur. Fish., Bull. 

 43:1-366. 

 JOSEPH, E. B. 



1972. The status of the sciaenid stocks of the middle 

 Atlantic Coast. Chesapeake Sci. 13:87-100. 

 KESTEVEN, G. L. (editor). 



1960. Manual of field methods in fisheries biology. FAO 

 Man. Fish. Sci. 1, 152 p. 

 MCHUGH, J. L. 



1960. The pound-net fishery in Virginia. Part 2 - Species 

 composition of landings reported as menhaden. Com- 

 mer. Fish. Rev. 22(2):1-16. 

 MASSMANN, W. H. 



1963. Age and size composition of weakfish, Cynoscion 

 regalis, from pound nets in Chesapeake Bay, Virginia 

 1954-1958. Chesapeake Sci. 4:43-51. 

 MASSMANN, W. H., J. P. WHITCOMB, AND A. L. PACHECO. 

 1958. Distribution and abundance of gray weakfish in the 



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