Haemulidae: E III B2

Pomadasys commersonnii (Lacepede 1801)

Spotted grunter

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
800-840	1	190-220	segmented	narrow	bow	43% of NL	26

Egg: The dense, pale yellow pigment in two lines down the developing embryo, breaking into two patches towards the tail, along with the segmented yolk and oil globule in the bow, served to identify this egg (A). Incubation is about 30 hours.

Larva: Early pigment patterns are shown in B & C, while a couple of variations in pigment intensity at 2 days, are shown in D & D1. At 3-4 days, the yellow pigment has faded, and scattered spots of black pigment can be seen in the gut area, and in a continuous dotted line down the ventral edge of the notochord to its tip (E). The 15-day larva is at the flexion stage (F), and the 17-day larva is postflexion (G). B: NH, C: 1 day, D: 2 days, E: 5 days, F: 15 days, G: 17 days, H: 30 days, I: 10 months (22-23°C).

These eggs were first recognised in samples from Durban Harbour mouth, where they were always collected fresh, as netting was conducted in the evening (see Introductory Notes under Methods). Apart from separating the various eggs by size, it was always necessary to incubate DHM samples until the following evening, when the embryo was well developed as in Plate A, and the eggs could be identified. Two species with similar eggs are Decapterus  (EIIIA6), and Pomadasys striatum (EIIIB3). Eggs of the former were hardly ever seen in the DHM samples, and it was assumed that the striped grunt was not present, an assumption at least partly born out by several reared batches. The species proved easy to rear, with up to 30% surviving to 30days. A number of malformed jaws and vertebrae were noted, however, apparently attributed to a deficiency in vitamin C ( T. Hecht, pers. comm.). About 50 were released back to the sea at 20-25mm SL and larger. Five larvae hatched from eggs from Durban harbour mouth have been barcoded, and match the barcodes of 5 locally collected adults (BOLD), and in November 2012, an egg were seen in an inshore sample at Park Rynie, and the hatched larva was barcoded. It is likely more would be recorded off Park Rynie, but they are very difficult to separate from P. striatum.

This was the third most common egg in the DHM samples (green graph, and Introductory notes, Section 7, Table 2). Spawning began in June and ran through to January in most years. The eggs were also collected from the ORI main tank in January 1988. They were only recorded at Park Rynie on one occasion, in November, but have probably been confused with Pomadasys striatum (EIIIB3) on occasion, since this look-alike egg is very common at Park Rynie. P. commersonnii eggs were recorded in Lake St Lucia, near the closed mouth, in September 1993, and above the Narrows, at Charters Creek in March, August and September 1994 (Connell, 1996).