Abstract.— Sectioned sagittae of 

 1,039 Spanish mackerel, Scombero- 

 morus maculatus (Mitchill), from the 

 Atlantic coast of the southeastern 

 United States (North Carolina to 

 Florida) were examined. The oldest 

 male was age 6 and the oldest fe- 

 male age 11. Marginal increment 

 analysis indicated that annulus for- 

 mation peaks in May^June. The von 

 Bertalanffy growth equation pa- 

 rameters (L , k, and t n , respectively) 

 were: 538mm fork length (FL), 0.31, 

 and -2.31 for males; 723 mm FL, 

 0.24, and -1.80 for females; and, 

 760 mm FL, 0.18, and -2.44 for sexes 

 combined. Gonads from 1,742 speci- 

 mens were examined histologically 

 to assess reproductive state. Mature 

 gonads were present in 89% of 

 age-0 males and 100% of older ages, 

 whereas 5% of females were mature 

 at age 0, 95% at age 1, and 100% at 

 older ages. Females matured at 288- 

 450 mm FL and males matured at 

 209-336 mm FL. Estimates of length 

 at 50% maturity (L m ) were 35.8 cm 

 FL for females and 23.9 cm FL for 

 males. Females were in spawning 

 condition from May to August; 

 ripe males were captured April- 

 November. Resting specimens were 

 included in the assessment of matu- 

 rity and the disadvantages of their 

 inclusion are discussed. 



Age, growth, maturity, and 

 spawning of Spanish mackerel, 

 Scomberomorus maculatus 

 (Mitchill), from the Atlantic Coast 

 of the southeastern United States* 



David J. Schmidt 

 Mark R. Collins** 

 David M. Wyanski 



Marine Resources Research Institute 



South Carolina Wildlife & Marine Resources Department 



PO Box 12559, Charleston, SC 29422-2559 



The Spanish mackerel, Scombero- 

 morus maculatus (Mitchill), is a mi- 

 gratory scombrid of importance to 

 commercial and recreational fisheries 

 in the Gulf of Mexico and along the 

 Atlantic coast of the southeastern 

 United States (Trent and Anthony, 

 1978). Concerns about overfishing 

 have prompted the establishment of 

 size and bag limits, as well as recre- 

 ational and commercial landings quo- 

 tas, with regulations based on the 

 hypothesis that there is an Atlantic 

 migratory group and one or more 

 Gulf of Mexico groups (SAFMC, 

 1988). Previous studies of the age and 

 growth of Spanish mackerel have 

 been based on specimens from the 

 Gulf of Mexico, or from southeastern 

 Florida where migratory groups are 

 thought to overlap (Klima, 1959; 

 Powell, 1975; Fable et al., 1987; 

 Helser and Malvestuto, 1987). Whole 

 sagittae were examined in these stud- 

 ies, but Collins et al. (1989) found 

 that ages from sectioned otoliths were 

 more accurate than those from whole 

 otoliths for the congeneric king mack- 

 erel (S. cavalla). Thus, age and 

 growth of Atlantic group Spanish 

 mackerel have not been rigorously 

 examined. 



The annual reproductive cycle of 

 Spanish mackerel has been described 

 (Klima, 1959; Beaumariage, 1970; 

 Powell, 1975; Finucane and Collins, 

 1986), but it has not been clearly es- 

 tablished histologically for the Atlan- 

 tic group. Klima (1959) and Powell 

 (1975) collected specimens from 

 southern Florida, an area where mi- 

 gratory groups may overlap. Of the 

 four studies cited, only Powell ( 1975) 

 used a histological technique. In pre- 

 vious studies of size and age at ma- 

 turity, specimens were not clearly 

 from the Atlantic group and age at 

 maturity was not quantified (see 

 Klima, 1959; Powell, 1975), and few 

 small females were examined (see 

 Klima, 1959; Finucane and Collins, 

 1986). The present study describes 

 the age, growth, size and age at ma- 

 turity, and reproductive cycle of Span- 

 ish mackerel from the Atlantic coast 

 of the southeastern United States. 



Methods 



Specimens were collected with hook- 

 and-line, trawls, gill nets, and block 

 (stop) nets. Spanish mackerel abun- 

 dance varies seasonally through most 



Manuscript accepted 23 April 1993. 

 Fishery Bulletin 91: 526-533 (1993). 



526 



Contribution No. 329 of the South Carolina Marine Resources Center. 

 ! *Address reprint requests to the second author. 



