Figure 4. A single set of growth parameters (Table 

 4) was calculated for C. equiselis since the largest 

 specimen in the sample had just reached sexual 

 maturity, and the calculation of separate growth 

 curves by sex was not warranted. The von Berta- 

 lanffy growth curve and 13 age-length relationships 

 of C. equiselis are shown in Figure 5. 



Discussion 



Validation 



A pair of otoliths was present at the time of hatch- 

 ing for both dolphins, and the first increment was 

 formed on the otoliths on D-l, identical to Kat- 

 suwonus pelamis, another tropical pelagic species 

 (Radtke 1983). The strong correlation of mean incre- 

 ment counts of sagittae to known age of fish 

 validated the use of growth increments in the aging 

 of C. equiselis up to 63 d and C. hippurus up to 191 

 d. Since regular incremental formation began on D-l, 

 no adjustment is required to the incremental counts 



140 



120 



100 



- 80 



I 

 I- 



o 



z 

 Id 



cc 

 O 



60 



40 



20 



/ 



^ 



MALES 



/ 



/ 



/ t\ ° 



/ / FEMALES 



// 



/ / 



Q IMMATURE (N =3) 

 o FEMALES (N =8) 

 A MALES (N =7) 



^^= VALIDATED 

 — == UNVALIDATED 



I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 

 ESTIMATED AGE (MONTHS) 



Figure 4— Von Bertalanffy growth curves of male and female Cory- 

 phaena hippurus in Hawaiian waters. 



Table 4.— Von Bertalanffy growth parameters calculated 

 from captured wild specimens of Coryphaena equiselis. 



Number 



Parameter 



Estimate 



SE 



13 



K 



0.0648 yr 

 2.1734 

 61.3914 cm FL 



0.0131 



0.9750 



17.8000 



of wild fish sagittae to estimate age Ideally, valida- 

 tion of daily increments should cover 1) the time 

 when the first daily increment is formed, 2) the 

 regularity in the formation of increments in all 

 stages of life, and 3) events such as spawning, migra- 

 tion, and periods of starvation which may affect the 

 regularity of increment formation. Having achieved 

 only part of these requirements, validation of daily 

 increments on otoliths should continue as older 

 known-age specimens become available, and the ef- 

 fects of spawning and starvation on increment for- 

 mation should also be examined. 



Growth of Wild Specimens 



The plot of age-length relationships of male C. hip- 

 purus showed that there was at least one extreme 

 variant. This 111.0 cm FL male greatly affected the 

 growth curve, resulting in a lower estimated L^ and 

 causing most of the male age estimates to fall below 

 the growth curve (Fig. 4). Thus, age-length relations 

 of wild C. hippurus should be examined further to 

 shed light on the extent of variation in size at given 

 ages. Additional age determinations might also im- 

 prove the confidence intervals of the von Bertalanffy 

 growth parameters. 



Growth rates of C. hippurus to age 1 around 

 Hawaii appeared to be greater than those reported 

 from the western North Atlantic Ocean. Beardsley 

 (1967) reported a mean length of 72.5 cm in age 

 group 1 for C. hippurus off Florida. Rose and 

 Hassler (1968) reported a mean length of 65.3 cm 

 at the end of 1 yr for fish off North Carolina. Around 

 Hawaii male C. hippurus were estimated to attain 



40 



30 



£ 20 



cc 

 O 



10 



"l r 



VALIDATED 



2 3 4 5 



ESTIMATED AGE (MONTHS) 



Figure 5.— Von Bertalanffy growth curve of Coryphaena equiselis 

 in Hawaiian waters derived from 13 age estimates. 



190 



