Mugilidae: L III A7

Liza dumerilii (Steindachner, 1869)*

Groovy mullet * and other species

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
865-980	1	290-350	clear	narrow	stern	60% of NL	24-25

Egg: The huge oil globule, in eggs about 1mm in diameter, make mullet eggs unmistakable (A). Lemon-yellow pigment on the embryo, a few stellate dots on the yolk, and an oil globule cloudy with yellow is typical, but some eggs lack spots on the yolk. Incubation is 30-35 hours. Note, in Plate A, that the buoyancy of the eggs has made all but the central egg, break the surface. The water-lines of two eggs are arrowed.

Larva: The 2-day larva usually has patches of yellow pigment in the finfolds, and at the anus (B). The larva in Plate C did not have finfold pigment, and is probably a different species. The 12-day larva is still preflexion (D), but by 15 days flexion is almost complete (E). B: 2 days, C: 4 days, D: 12 days, E: 29 days (23-24°C).

Mullet are easy to rear, and are precocious in their development. In my rearing tanks, I noted they had developed a silver saddle on their backs at 20 days. Off Park Rynie, these silver-back juveniles form small shoals near the surface, the conspicuous shine making them easy to spot from a boat travelling slowly along driftlines. Clusters the size of a tennis ball and comprising 50-100 juveniles, are commonly seen, closing ranks as the boat approaches. I have also seen them entering open estuaries on the incoming tide, in these same clusters, although more usually in 1’s and 2’s. Only 1 larval sequence is available, which matches the sequence of 3 adult L. dumerilii collected locally (BOLD). Doubtless, more species will be found in this complex, as DNA results accumulate. Harrison (2003) lists 11 species of mullet which he collected in KZN estuaries.

Under this particular code, (LIIIA7) I deliberately catalogued only small mullet eggs in the DHM sampling. When encountered offshore, the smaller mullet eggs were catalogued under LIIIB7, and the larger ones under LIIB9.

This was the 5^th most common egg in the DHM samples, mostly seen in winter and spring (green graph).