NOTE Sutter et al.: Growth and mortality of Scomberomorus cavalla tagged in southeastern U.S. 



735 



Table 3 



Summary of theoretical growth parameters (L^, K) and mortality estimates (Z), sexes combined, for Gulf of Mexico and Atlantic 

 migratory groups of king mackerel Scomberomorus cavalla. 



Study 



Migratory group 



Interval 



L„, (cm) 



K 



Present study 



Manooch et al. (1984) 



Collins et al. (1988) 



Gulf of Mexico 



Atlantic 



Gulf of Mexico 



Atlantic 



1975-88 1 



1975-85 1 



1980-85 



1983-87 



'Time from release to recapture used in calculating growth parameters. 



= Years used in regression analysis of recaptured king mackerel. 



3 Year fish collected from recreational hook-and-line catches in northwest Florida. 



4 Year fish collected from gillnet catches in south Florida. 



5 Year fish collected from south Florida purse-seine catches. 

 "Whole otoliths. 



"Sectioned otoliths. 



Results and discussion 



Growth analysis 



A total of 9010 king mackerel from the Gulf of Mexico 

 king mackerel migratory group were tagged; 794 were 

 reported recaptured, and 439 fulfilled our criteria for 

 inclusion in the growth analysis. The mean length-at- 

 tagging was 74.5cm FL (SD 8.92cm, range 42.5-120.0 

 cm) (Fig. la), while the mean length-at-return was 

 85.2cm FL (SD 11.61cm, range 62.5-133.0cm) (Fig. 

 lb). Maximum time-at-large was 10.48 years (3829 

 days), with a mean of 1.06 years (SD 1.24 yr). Fish were 

 recaptured most frequently during the first year of 

 freedom (51.5%), with seasonal increases in returns 

 noted during winter and spring months (Fig. 2a). We 

 recaptured Gulf of Mexico migratory group fish from 

 Texas to southeast Florida through 1988, although 

 95.5% were taken before 1981. 



The relationship between length-at-return minus 

 length-at-tagging (At 1 ) vs. number of days-at-large (At) 

 for Gulf of Mexico king mackerel was described by: 

 AC =3.722 + 0.012 (At) (r 2 0.503; df 1, 438; P<0.01). 

 Mean values from a total of 63 30-day blocks were used 

 to generate an estimate of L 0O = 132.6cm FL (95% CI 

 114.3-150.8cm), and K = 0.127 (95%CI 0.068-0.186). 

 Manooch et al. (1987) used whole otoliths to calculate 

 an L^ value of 147.8cm (95% CI 131.6-164.0cm) and 

 K = 0.115(95%CI 0.079-0. 152) for Gulf of Mexico king 



mackerel captured during 1980-85 (the majority taken 

 from Key West, northwest Florida, and Texas), com- 

 bining both sexes (Table 3). Growth parameters deter- 

 mined from our tagging study overlap the spatial and 

 temporal constraints of their age-length data. 



A total of 3483 king mackerel were tagged from the 

 Atlantic king mackerel migratory group. Recaptures 

 were reported for 253 fish, of which 157 provided suf- 

 ficient data for our growth analysis (Fig. lb). Mean 

 length-at-tagging was 81.0cm FL (SD 9.17, range 

 50.0-122.5 cm), while the mean length-at-return was 

 91.0cm FL (SD 11.65, range 64.8-127.0). The max- 

 imum time-at-large was 6.47 years (2361 days), with 

 a mean of 1.56 years (SD 1.41 yr). Fewer returns were 

 reported during the first year of freedom (31.2%) than 

 were noted for the Gulf migratory group (Fig. 2b), and 

 most returns occurred during the summer and fall. We 

 recaptured Atlantic migratory-group king mackerel 

 through 1985; however, 92.1% were taken before 1982, 

 prior to commercial and recreational quota restrictions. 



The relationship between growth (AC) and time-at- 

 large (At) for the Atlantic fish is: AC = 4.057 + 0.008 (At) 

 (r 2 0.323; df 1, 156; P<0.01). The estimated asymp- 

 totic length for Atlantic king mackerel calculated from 

 52 30-day blocks was 152.0cm FL (95% CI 87.3-216.8 

 cm), with an associated K = 0.070 (95% CI 0.005-0.146). 

 Collins et al. (1988) used whole and sectioned otoliths 

 from king mackerel in the Atlantic group to calculate 

 estimates of L = 112.7 and 127.7cm FL, and K = 0.213 



