Sparidae: L III D1

Lithognathus mormyrus (Linnaeus, 1758).

Sand steenbras

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
910-940	1	170-190	clear	narrow	stern	40% of NL	24

Egg: The partly incubated egg has a number of yellow spots on the yolk, especially near the oil globule (A). The more advanced egg has 6 bright yellow patches on the embryo, and the stellate yellow spots on the yolk have reduced to just a few (B). The oil globule is clear to pale amber. Incubation is about 30 hours. The egg tends to sink during the later stages of incubation.

Larva: The 1-day larva (C) has yellow pigment in the finfold and adjacent notochord, which reduces over the next 3 days (D-G), and has completely disappeared, except for small remnants around the anus, by day 5 (H). Black pigment concentrates over the gut, and in a dotted line ventrally along the notochord (H). C: 1 day, D & E: 2 days, F: 3 days, G: 4 days, H: 5 days (22-24°C).

Brownell (1979) illustrates an egg and larva which he attributes to this species, based on comparison with Varagnolo’s (1964) description of L. mormyrus from the Adriatic Sea. Both these descriptions do not include yellow pigment in the finfolds, which was originally described by Gilchrist (1903) and referred to by Brownell as “contradictory”. The meristics and shape of Brownell’s 56 day larva at 11.7mmSL (D XI,12; A III,11; P 16) could fit Rhabdosargus globiceps.

But for the position of the oil globule and clear yolk, the early larvae would be easily confused with EIIIA6, due to the finfold pigment. I did not manage to rear this species, despite good numbers of eggs in some samples. All 8 hatched larvae sequenced so far, have matched the sequences of 7 adult L. mormyrus from the KZN and Cape coasts (BOLD reference).

Linked samples	Offshore	Inshore
Eggs	332	642
Hits	50	108

This egg was fairly common off Park Rynie, and was seen most months of the year (blue graph). The egg was not seen in the DHM samples, which is surprising, in view of the species shallow water preference. Annual catches off Park Rynie, have shown an increase in recent years (white graph). The Park Rynie linked samples showed the majority of eggs inshore (66%). suggesting this species is spawning very close to shore, probably in less than 10m water depth, close to the surfzone. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.