DEVELOPMENT OF EGGS AND LARVAE OF 

 CARANX MATE (CARANGIDAE)i 



John M. Miller and Barbara Y. Sumida^ 



ABSTRACT 



The development of eggs and larvae of omaka (Caranx mate) is described from approximately 

 2 h after fertilization to day 36 after hatching. The pelagic, spherical eggs (700-740 /i diameter) 

 had a single oil droplet and hatched after about 26 h incubation at 24.5°C. The average 

 growth rate in culture was 0.44 mm/day; feeding began four days after hatching. Fin develop- 

 ment and ossification of omaka occurred at smaller sizes, but in the same sequence as jack 

 mackerel (Trachurus symmetricus) off California. Of the body proportions measured, body 

 depth was most useful in separating omaka from at least two other species of carangid larvae. 

 The pigment pattern was also of diagnostic value. Reared larvae were indistinguishable 

 from similar-sized field specimens. 



Omaka {Caranx mate) is one of the most abundant 

 carangids in the Hawaiian Islands. The species 

 is rather widespread throughout the Indo-Pacific, 

 reaching the eastern coast of Africa. In Hawaii, 

 the preferred habitats are estuaries, bays, and 

 harbors with relatively long water residence 

 times. Kuthalingham ( 1959) described the feeding 

 habits of omaka near Madras, India. The growth 

 rate of captive adult omaka was reported by 

 Watarai (1973). 



Omaka have a protracted spawning period in 

 Hawaii; the eggs can be taken with fair regu- 

 larity from March through September from the 

 surface waters of Kaneohe Bay, Oahu. Little else 

 is known of the spawning habits. However, a bi- 

 weekly year-round fish-egg survey in Kaneohe 

 Bay indicated three spawning peaks: one in April 

 and May, another in September and October, 

 and a third, smaller, peak in July (Watson and 

 Leis, 1973).^ During these peaks omaka eggs were 

 by far the most abundant of any, occasionally 

 exceeding concentrations of 10/m^ in the surface 

 waters of south Kaneohe Bay. Larval densities, 

 on the other hand, were found to be much lower 

 than these egg densities, rarely reaching 0.1/m^ 

 (Watson and Leis, see footnote 3). As is char- 

 acteristic of many carangids, young are frequently 



'Hawaii Institute of Marine Biology Contribution No. 427. 



^Hawaii Institute of Marine Biology, University of Hawaii, 

 Coconut Island— P.O. Box 1346, Kaneohe, HI 96744. 



^Watson, W., and J. M. Leis. 1973, Ichthyoplankton in 

 Kaneohe Bay: A one-year study of the fish eggs and larvae. 

 Unpubl. manuscr. 



seen under medusae. Large larvae and juveniles 

 are similarly attracted to floating raffia, and have 

 been collected in this manner. Adult omaka do 

 not appear to make the off'shore spawning move- 

 ments characteristic of many of the resident fish 

 species in Kaneohe Bay. 



MATERIALS AND METHODS 



Larvae used for description came from two 

 sources: reared specimens and field specimens. 

 Reared larvae of known age were the primary 

 source of material; field specimens were used 

 mainly to verify observations and conclusions 

 based on the former. Over the past 2 yr omaka 

 larvae have been taken in numerous plankton 

 tows. Each time that comparisons were made 

 between similar-sized field and reared specimens, 

 the larvae were indistinguishable. 



Larvae were obtained from two cultures (called 

 Series A) begun in February 1971. One of these 

 (Al) supplied larvae through day 5 (Table 1). 

 This culture was terminated on day 6, when high 

 mortality (of unknown cause) was experienced. 

 Although the sizes of these larvae are included 

 in the growth rate curve (Figure 4), they were 

 not used in the description of developmental 

 stages. The second (A2) was maintained for 36 

 days during which post yolk sac specimens (day 

 6 and older) were taken for description. 



Two other cultures (Series B) were begun in 

 May 1972 to provide eggs and yolk-sac larvae. 

 The first, begun 1 May, was to determine the 

 approximate rate of development and design a 



Manuscript accepted September 1973. 

 FISHERY BULLETIN: VOL. 72, NO. 2. 1974. 



497 



