COLLINS ET AL.: AGE AND GROWTH OF KING MACKEREL 



• Whole 



X Sectioned 



E 

 E 



^ o 



c 



Mt 



1 3 6 7 a 11 13 15 17 19 21 



Age (years) 



Figure 6.— Mean back-calculated lengths at age from whole and from sectioned 

 otoliths for male and female king mackerel. 



by Van Oosten (1929) and restated by Beamish and 

 McFarlane (1983), procedures that produce direct 

 evidence and validate ages of all age groups include 

 mark-recapture techniques (which wall involve chem- 

 ical labeling if ages are to be determined from oto- 

 liths) and capture of known-age fish. The only pre- 

 vious study of king mackerel producing acceptable 

 evidence for age validation (Manooch et al. 1987) 

 generated very different life history characteristics 

 from ours, including maximum ages of 11 and 14 



for males and females, respectively, but was based 

 on whole otoliths from Gulf of Mexico fish. Thus, 

 whether the differing results are due to sepa- 

 rate groups of king mackerel with different life 

 history characteristics or to differences in tech- 

 niques is not known. Regardless, we have demon- 

 strated that dubious information from whole oto- 

 liths can appear valid, and suggest that sectioned 

 sagittae be used to age king mackerel in future 

 studies. 



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