Carangidae: E II A4

? Seriola rivoliana Valenciennes, 1833.

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
1000-1175	1	260-270	segmented	narrow	bow	60% of NL	24

Egg: This egg will always need to be hatched to confirm identification. Often, the oil globule gives the impression of positioning itself astern in the developing embryo, and the bright yellow pigment is reminiscent of Scomber (LIIA7), but the densely segmented yolk will rule out Scomber. The oil globule becomes evenly peppered with black pigment spots ventrally. Incubation takes about 45 hours..

Larva: The strikingly pigmented 1-day larva is always spectacular (B). The 5-day larva is a mixture of grey pigments (D & E), similar to other Seriola species (EIIA2). B: 1 day, C: 2 days, D & E: 5 days (25°C).

This is possibly the tropical yellowtail, Seriola rivoliana. Rearing attempts were unsuccessful. Seven larval DNA sequences are currently available, but results are confusing. Two match 2 locally collected adult S. rivoliana, but 5 match S. dumerili (BOLD reference). The confusion between EIIA2 and this page, will require careful separation of future eggs, and barcoding of the hatched larvae.

 

Linked samples	Offshore	Inshore
Eggs	170	37
Hits	14	9

This species is a summer spawner in KZN waters (blue graph). The egg was not seen in DHM samples. The Park Rynie eggs per year trend, shows a patchy presence (white graph). The Park Rynie linked samples had 82% offshore, indicating spawning in the same area as kob (LIIIA8), in 30-50m water depth. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.