Sillaginidae: F III A4B

Sillago cf sihama (Forsskal 1775)

Sand smelt

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
790-865	1	190-220	segmented	narrow	stern	46% of NL	ca 32

Egg: The bright orange-yellow pigment spots on the embryo, are quite large, and clustered laterally, to form two bands down the body (A). They also cover, or ring, the oil globule (A & B). Some eggs may have a greener tint to the yellow pigment. Incubation time is about 25 hours (24°C).

Larva: The 2-day larva is quite elongate, with a distinctive pigment pattern (C), which becomes an almost continuous line from head to tail-tip, above and below on the notochord (D). B: NH, C: 2 days, D: 3 days (24°C).

The early larva yellow pigment pattern, segmented yolk, and oil globule in the stern, add up to a larva which can only be confused with FIIIA7. It has not been seen off Park Rynie, but was fairly common in the Durban Harbour mouth samples (green graph). The egg was found in St Lucia during September 1993 (Connell, 1996), and was identified as Sillago sihama, based on illustrations in Ikeda & Mito (1988). During the present study, 22 adult specimens of Sillago, which all key out to S. sihama (McKay, 1986), have been successfully sequenced, revealing 4 cryptic species in KZN waters (BOLD). On 8 February 2009 two of these eggs were collected from Durban Harbour mouth, and have matched 14 locally collected adults, which represent one of the 4 cryptic species of Sillago mentioned above. Until these adults have been carefully assessed by an expert on the genus, the species remains uncertain.

This egg has not been seen in the Park Rynie samples. In the DHM samples, collections suggest a spring to early summer spawning peak (green graph).