Kyphosidae: E III A1A

Kyphosus bigibbus Lacepede, 1801

Grey chub

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
910-985	1	220-250	segmented	narrow	bow	48% of NL	27

Egg: The striking feature of this egg is the two rows of splashy yellow pigment dots, starting with a pair behind the eyes, and running down the length of the embryo, plus a couple on the oil globule (A). On a white background, two rows of fine stellate black pigment dots will be seen, close together, dorsally along the notochord. The egg sometimes has a slightly widened perivitelline space. The oil globule is clear. Incubation takes about 35 hours.

Larva:  The 2-day larva has a characteristic yellow pigment pattern (B). By day 5, the yellow pigment is deeper yellow, and the dorsal black pigment has consolidated along the notochord, above and posterior to the anus (C & D).  B: 2 days, C: 4 days (23°C).

This egg and larva are similar to Oplegnathus fasciatus (Ikeda & Mito 1988, pg 1045), and the egg is similar to the Shao et al (2001) illustration of the egg of O. punctatus (pg 104). It was thus assumed to be the egg of O. conwayi, since DNA barcoding has assigned EIIIA2 to O. robinsoni, the other Oplegnathus in KZN waters (Heemstra, 1986). However, subsequent barcoding of larvae of FIIA7, has indicated that as O. conwayi. Larvae hatched from 10 eggs have matched 2 adult Kyphosus bigibbus collected locally (BOLD).

This egg was rare off Park Rynie, having been seen only 8 times in 25 yers (blue graph), all in late summer and autumn. In the Park Rynie linked samples, 21 out of 30 eggs were in inshore samples (70%), inicating spawning close inshore, but numbers are small.