FISHERY BULLETIN: VOL. 84, NO. 4 



Table 2.— Total sample number and percentage of mature (Stages lll-V) king mackerel females 

 collected during the peak maturation season in each area. 1 



'Area I, June-August; Area II, May-August; Area III, May-September; and Area IV, June-September. 



Factors influencing the maturation cycle of king 

 mackerel are not well known. Presumably, photo- 

 period and water temperature are important for 

 spawning, egg, and larval development. Beau- 

 mariage (1973) indicated that seasonal changes 

 in photoperiod influenced the spawning of king 

 mackerel while McEachran et al. (1980) noted that 

 larvae were more abundant at temperatures 

 from 20.2° to 29.8°C and salinities from 28.2 to 

 34.47oo. A study by MacGregor et al. (1981) also 

 showed that the levels of serum androgens and 

 estrogens may be indicators of maturation in king 

 mackerel. 



Our inferences on spawning peaks and activity of 

 king mackerel, as determined by largest mean EDs, 

 usually coincided with those of other studies. Our 

 largest mean ED of 0.61 mm agrees with the 0.60 

 mm reported by Alves and Tome (1967). In contrast, 

 the largest mean ED of 0.33 mm shown by Beau- 

 mariage (1973) suggests that most of his fish were 

 not ready to spawn. Our largest mean egg sizes from 

 northwest Florida fish were similar to those re- 

 ported by Beaumariage (1973) and probably in- 

 dicates that spawning activity off the west coast of 

 Florida is not extensive. Peak spawning months by 

 area in this study were area I, August; area II, May; 



area III, August; and area IV, July. In the north- 

 western and northeastern gulf, (our areas I and III) 

 the highest catches of larval king mackerel occurred 

 during September (Dwinell and Futch 1973; 

 McEachran et al. 1980). Houde et al. (fn. 2) stated 

 that because of their rare catches of larvae, king 

 mackerel does not appear to spawn frequently in the 

 eastern gulf. 



The reproductive cycle of king mackerel off the 

 coast of Brazil is probably similar to that of this 

 species from American waters. Ivo (1972) noted that 

 spawning occurred throughout the year off the state 

 of Ceara which is south of the Equator. Other 

 studies indicate that they begin to spawn from Octo- 

 ber through December (Menezes 1969) with peaks 

 in November and March (Gesteria and Mesquita 

 1976). Since the seasons are reversed in this area, 

 they would correspond to our spring and late sum- 

 mer spawning peaks for king mackerel. 



We were unable to determine the number of times 

 individual king mackerel spawn during the year 

 from the data. Beaumariage (1973) concluded that 

 king mackerel were multiple spawners, based on 

 their extended spawning season and presence of 

 several modal groups of yolked eggs. Morse (1980) 

 reported that individual Atlantic mackerel, Scomber 



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