486 
Fishery Bulletin 108(4) 
Figure 4 
Size-at-age relationships of sailfish ( Istiophorus platypterus ) larvae collected from the 
northern Gulf of Mexico in 2005 and 2006 arranged by survey. Age in days was determined 
from otolith microstructure analysis. Exponential equations are given. 
Table 5 
Instantaneous weight-specific growth ( G ) and mortality ( Z ) coefficients of sailfish ( Istiophorus platypterus ) larvae collected from 
the northern Gulf of Mexico in 2005 and 2006. Percentage per day was calculated from instantaneous growth and mortality coef- 
ficients. The G:Z index of stage-specific production potential is also shown. 
Year 
Survey 
G 
%/d ay 
Z 
%/day 
G:Z 
2005 
May 
0.371 
44.9 
0.285 
24.8 
1.30 
July 
0.378 
45.9 
0.228 
20.4 
1.66 
September 
0.347 
41.5 
0.345 
29.2 
1.01 
All surveys 
0.371 
44.9 
0.288 
25.0 
1.29 
2006 
June 
0.351 
42.0 
0.344 
29.1 
1.02 
August 
0.347 
41.5 
0.381 
31.7 
0.91 
All surveys 
0.347 
41.5 
0.394 
32.6 
0.88 
