Sparidae: L III C1C

Sparodon durbanensis (Castlenau, 1861)

Brusher or white musselcracker

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
890-910	1	190	clear	narrow	stern	? of NL	24

Egg: No description of the egg is available. It must be assumed that it is similar, both in size and pigment pattern, to blacktail, from which the measurements are taken for the above table.

Larva: Known only from this juvenile, found in a rearing tank containing about 12 small blacktail (LIIIC1)  A: 107 days (22-25°C).

The batch of eggs from which this juvenile was reared, was collected on 24 August 1996. The sample contained over 200 eggs, of which about 80 were catalogued as blacktail, and placed in a rearing tank for confirmation. Only when the tank was cleaned out, and the surviving blacktail released, was it apparent that one was a juvenile S. durbanensis. It was photographed and preserved as a voucher specimen. Three hatched larvae have been barcoded (submitted under the code LIIIC1and LIIIC1B), and they matched the sequences of 5 adults collected on the KZN coast (BOLD).

Sparodon durbanensis is another of the endemic South African sparids which moves up the east coast from the eastern Cape, into KZN waters in winter. Whether they move into KZN waters to spawn is unknown; it might be that they simply expand their range into KZN waters in winter, due to cooler inshore water, and this coincides with their spawning condition. But while in KZN waters, usually from August to October, the fish have large, active gonads. They are heavily targeted by surf anglers, since this is a large, powerful fish which feeds almost exclusively in and about the surf zone. They are known to spawn along the Cape coast (Smith & Smith, 1986), and Brownell (1976) illustrates a 13mm SL juvenile from a False Bay rock pool.

Careful separation of blacktail eggs and early larvae will undoubtedly lead to DNA sequences uncovering more of these eggs, and hopefully some pointers to distinguishing them.