Coryphaenidae: F II A4

Coryphaena hippurus Linnaeus, 1758.

dorado

Egg diameter in µm	Number of oil globules	Diameter of oil globule in µm	Yolk texture	Perivitelline space	Position of oil globule at hatch	Gut length   at eye- pigment stage	Myomeres
1320-1560	1	265-340	segmented	narrow	stern	59% of NL	30

Egg: The light amber oil globule and exaggerated segmentation of the yolk usually identify this species.   Fine yellow and black pigment dots are evenly distributed on the embryo, the black spots becoming stellate on the head.  Incubation is about 50 hours (25°C).

Larva: The NH larva has unpigmented eyes and an unformed mouth. Greenish/yellow pigment lines the finfold edge (C), becoming whiter as the larva develops (E & F).  By day 6 it is fading. C: NH, D: 1 day, E: 2 days, F: 4 days, G: 6 days (25°C).

No effort was made to rear this species as the eggs are well illustrated in the literature (eg Ikeda & Mito 1988, pg 1047). Note however, that Shao et. al. (2001) show two larvae under this species, which appear to be two stages of a monodactylid ( their Plates B & C pg 76), while what appears to be the early larva of  C. hippurus is shown on page 57 (Plate B) as a gurnard. Two larvae have been barcoded, and they match 5 locally collected adults.

Linked samples	Offshore	Inshore
Eggs	210	32
Hits	74	19

Dorado are summer visitors to KZN waters, and spawn while in our waters (blue graph). This is in contrast to the two Scomberomorus species (commerson and plurilineatus), which move into our waters over the same period, but do not spawn here (van der Elst 1981). The annual catch of eggs at Park Rynie (white graph), showed a marked increase during the past 8 years. The Park Rynie linked samples had 87% offshore, indicating spawning around the 50m contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.