Sciaenidae: L II B6

Umbrina robinsoni Gilchrist & Thompson 1908

Slender baardman

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
1000-1060	1	220-250	clear	narrow	stern	41% of NL	25

Egg: Fresh eggs have a clear to light amber oil globule, and due to their common size, are indistinguishable from a group of triglids, sparids and cheilodactylids. Big black and smudgy orange-yellow stellate pigment spots develop on the embryo later (A), and the oil globule darkens due to black pigment ventrally. Incubation is about 48 hours.

Larva: The dense brown-black pigment surrounding the notochord from shoulder to mid-tail, additionally spotted with orange-yellow pigment (B), distinguishes this early larva from all others in the area, except LIIIA4.  At 3-5 days the dark pigment has re-arranged into the pattern shown in Plates C & D, with the distinctive shoulder patch extending into the dorsal finfold. At 21 days the larva was postflexion (E). This species proved quite easy to rear. Plate F shows a 50-day juvenile swimming in the rearing tank, and Plate G is a 100-day juvenile. B: 1 day, C: 3 days, D: 5 days, E: 21 days, F: 50 days, G: 100 days (23°C).

DNA barcodes are available for 6 larvae hatched from this egg, and they match the sequences of 5 adult Umbrina robinsoni collected from the KZN coast (BOLD).

Linked samples	Offshore	Inshore
Eggs	32	139
Hits	25	58

This was a fairly uncommon egg off Park Rynie, seen in samples all year round, though peaking in winter and spring (blue graph). It was only seen once in the DHM samples, in July. The capture of eggs at Park Rynie, through the 19 years of sampling, has remained fairly steady (white graph). The Park Rynie linked samples showed more of these eggs inshore (81%), suggesting spawning around the 15m contour, in keeping with this species known preference for inshore reefs (K Hutchings pers. comm.). See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples. .