Growth and Mortality of King 

 Mackerel Scomberomorus cavalla 

 Tagged in the Southeastern United States 



Frederick C. Sutter III 



Florida Marine Research Institute, Department of Natural Resources 

 100 Eighth Avenue SE, St. Petersburg. Florida 33701-5095 



Roy O. Williams 



Florida Marine Fisheries Commission, 2540 Executive Circle West 

 Suite 106, Tallahassee, Florida 32301 



Mark F. Godcharles 



Southeast Region, National Marine Fisheries Service, NOAA 



Duvai Building, 9450 Koger Boulevard, St Petersburg. Florida 33702 



King mackerel Scomberomorus ca- 

 valla is a heavily exploited coastal 

 pelagic scombrid that has received 

 considerable attention from research 

 and management concerns through- 

 out the southeastern United States 

 (Gulf of Mexico and South Atl. Fish. 

 Manage. Counc. 1985). Age-length 

 data from analyses of otoliths have 



recently been used to estimate 

 growth and mortality of the Gulf of 

 Mexico migratory ("stock") group 

 (Manooch et al. 1987) and growth of 

 the Atlantic group (Collins et al. 

 1988). Previous studies did not dif- 

 ferentiate between Gulf and Atlan- 

 tic groups (Beaumariage 1973, 

 Johnson et al. 1983). Length-incre- 



Table 1 



Number of king mackerel Scomberomorus cavalla tag releases off southeastern United 

 States by year, 1975-79, and migratory group. 



Location and month of release/Migratory group 



Year 



Ft. Pierce, FL 



December-March/ 



Gulf of Mexico 1 



Florida Keys 



February, March/ 



Gulf of Mexico 2 



Jupiter, FL 



May, June/ 



Atlantic 3 



S. Carolina 



May, June/ 



Atlantic 4 



1975 

 1976 

 1977 

 1978 

 1979 



Total 



880 

 1904 

 1666 

 1966 



6416 



974 



844 

 776 



2594 



372 



1318 



588 



396 



2674 



809 

 809 



1 For all years except 1975, the annual totals for the Ft. Pierce area include December 

 releases of the previous year. Northern boundary of the release area was defined by 

 28°45'N lat. and the southern boundary by 27°07'N lat. 



2 Eastern boundary of the release area was defined by 81 ° 10'W long., southern boundary 

 by 24°10'N lat., western boundary by 83°30'W long., and northern boundary (Gulf 

 of Mexico only) by 27°00'N lat. 



3 Northern boundary of the release area was defined by 27°07'N lat. and southern 



boundary by 26°19'N lat. 

 4 Northern boundary of the release area was defined by 33°50.0N lat. and southern 



boundary by 32°03.0'N lat. 



ment (tag return) data can also be 

 used to estimate growth and mor- 

 tality; however, the growth param- 

 eter values generated from these 

 data may not be directly compar- 

 able with those developed using 

 age-length information (Francis 

 1988). In this report, we present 

 estimates of growth and mortality 

 based on mark-recapture data for 

 both the Gulf and Atlantic king 

 mackerel groups. 



Methods 



King mackerel captured by hook- 

 and-line were marked with internal 

 anchor tags along the southeastern 

 United States from South Carolina 

 to the Florida Keys during 1975 to 

 1979 (Sutter et al. 1991). Tagged 

 fish were assigned to the Gulf or 

 Atlantic migratory groups (Table 1) 

 based on location and date of re- 

 lease using current stock definitions 

 (Powers and Eldridge 1983). King 

 mackerel tag returns that did not 

 show negative growth (based on 

 reported length) were grouped into 

 30-day intervals based on time-at- 

 large. The mean change in length 

 between release and recapture and 

 the mean time-at-large were deter- 

 mined for each 30-day period. Use 

 of means within blocks eliminated 

 the unequal weighting caused by 

 the large number of fish returned 

 less than one year after release, or 

 by any periodicity in seasonal recap- 

 tures. These values were used to 

 estimate the von Bertalanffy growth 

 parameters L^ (asymptotic size) 

 and K (growth rate constant) using 

 a non-linear solution (SAS 1985) of 

 Fabens (1965) method. We did not 

 have enough fish to partition our 

 data further to describe growth 

 parameters for male and female 

 king mackerel. 



Mortality estimates were made 

 separately for Gulf of Mexico and 

 Atlantic king mackerel groups. 



Manuscript accepted 22 July 1991. 

 Fishery Bulletin, U.S. 89:733-737 (1991). 



733 



