REPRODUCTIVE BIOLOGY OF KING MACKEREL, SCOMBEROMORUS 

 CAVALLA, FROM THE SOUTHEASTERN UNITED STATES 



John H. Finucane, L. Alan Collins, Harold A. Brusher, 

 and Carl H. Saloman 1 



ABSTRACT 



The reproductive biology of king mackerel, Scomberomorus cavalla, was studied from specimens collected 

 off Texas, Louisiana, and northwest Florida in the Gulf of Mexico and off North and South Carolina 

 in the Atlantic Ocean. Gonads were examined from 1,163 females and 595 males obtained in 1977-78. 

 Spawning was prolonged. Most king mackerel were reproductively active from May through September. 

 A few fish were in spawning condition as early as April and as late as October. All females were mature 

 at 850-899 mm fork length (FL). Estimates of fecundity ranged from about 69,000 to 12,207,000 eggs 

 for fish from 446 to 1,489 mm FL, 618 to 25,610 g total weight (TW), and 1 to 13 years of age. Fecundity 

 (F) was usually significantly correlated with FL, TW, and age in each area but TW was the best predic- 

 tor of fecundity in all areas combined (F = 1.854 x 10 1 (TW) 1 ' 361 ) with r 2 = 0.856. 



King mackerel, Scomberomorus cavalla, is one of the 

 most valuable commercial and recreational fish in 

 the Gulf of Mexico and south Atlantic. It is an 

 epipelagic, neritic species that occurs in the western 

 Atlantic Ocean from Massachusetts to Rio de 

 Janeiro, Brazil (Collette and Russo 1979, 1984). Most 

 of the king mackerel caught off the southeastern 

 United States are landed in Florida (Manooch 1979) 

 where it is an important component of charter boat 

 catches (Moe 1963; Brusher et al. 1978). Commer- 

 cial landings in Florida during 1983 totaled 2,017 

 t and the estimated recreational catch from the Gulf 

 of Mexico was 1,090,000 fish in 1984 (U.S. Depart- 

 ment of Commerce 1985a, b). 



Although much has been written on king mack- 

 erel, little is known of its reproductive biology 

 (Manooch et al. 1978). Ovarian histology and size- 

 at-maturity has been described by Alves and Tome 

 (1967) for fish from Brazil and by Beaumariage 

 (1973) for fish from Florida. Maturation based on 

 blood hormone levels from fish off northwest Florida 

 was reported by MacGregor et al. (1981). Spawn- 

 ing times and areas have been inferred from ichthyo- 

 plankton collections of king mackerel larvae (Dwinell 

 and Futch 1973; Finucane and Collins 1977; Houde 

 et al. 1978 2 ; McEachran et al. 1980). The only fecun- 



'Southeast Fisheries Center Panama City Laboratory, National 

 Marine Fisheries Service, NOAA, 3500 Delwood Beach Rd., 

 Panama City, FL 32407-7499. 



2 Houde, E. D., J. C. Leak, C. E. Dowd, S. A. Berkely, and W. 

 J. Richards. 1979. Ichthyoplankton abundance and diversity in 

 the eastern Gulf of Mexico. Part I: Executive summary, abstract, 

 text reference. Unpubl. manuscr., 119 p. Draft Final Report to 



dity estimates in the literature were made by Ivo 

 (1974) for fish from Brazil. 



The purpose of our study was to provide additional 

 information on king mackerel reproductive biology 

 by determining spawning season, length-at- 

 maturity, and fecundity from four areas off the 

 southeastern coast of the United States. This infor- 

 mation will be useful in the management of king 

 mackerel since the measure of reproductive poten- 

 tial is a basic element of productivity and stock 

 dynamics (Baglin 1982). 



METHODS 



King mackerel were sampled from commercial 

 and recreational catches in four separate areas along 

 the coast of the southeastern United States during 

 1977 and 1978 (Fig. 1). These areas were I, the 

 northwestern Gulf of Mexico off the central and 

 south coasts of Texas; II, the northcentral Gulf off 

 Louisiana and Mississippi; III, the northeastern Gulf 

 off northwest Florida; and IV, the western Atlan- 

 tic Ocean off South and North Carolina. 



Procedures for processing gonads, weighing, and 

 measuring fish followed the methods of Finucane 

 and Collins (1984). If no total weight had been 

 recorded for a fish, we estimated TW by using the 

 formula TW = 1.4959 x 10 " 5 (FL) 2 - 89284 (TW = 

 total weight in grams; FL = fork length in milli- 

 meters). This formula (Ricker 1975) was derived 



Manuscript accepted April 1986. 



FISHERY BULLETIN: VOL. 84, NO. 4, 1986. 



Bureau of Land Management, Contract AA550-CT7-28. Rosen- 

 stiel School of Marine and Atmospheric Science, University of 

 Miami, Miami, FL 33149. 



841 



