Sphyraenidae: E III A2A

Sphyraena obtusata Cuvier, 1829.

Obtuse barracuda

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
940-1010	1	240-265	segmented	narrow	bow	64% of NL	25

Egg: When seen at the stage photographed (A), the distinguishing feature of this egg is the ring of yellow pigment around the oil globule. On a white background, black pigment dots will be seen ventrally on the oil globule. The embryo has yellow behind each eye, and two rows of yellow pigment down the length of the body. The oil globule is clear. Incubation is 30-35 hours.

Larva: The 1-day larva has a distinctive yellow pigment pattern (B). By day 4, the yellow pigment is fading, and the body is elongating (C). At day 5, black pigment has become prominent both dorsally and ventrally along the notochord, interspersed with yellow (D & E).  B & B1: 1 day, C: 4 days, D & E: 5 days (23°C).

Originally I assumed this was a carangid, based on the pigment of the early larva. The elongate larva at 4-5days is, however, unlike most carangids. Seven larvae from this egg have been DNA barcoded, but a match has not yet been found among the 4 local species of Sphyraena for which adult barcodes are currently available (S. acutipinnis, S. barracuda, S. chrysotaenia and S. jello). In my barcode dendrogram, it is closest to Sphyraena chrysotaenia, though not a match (BOLD). Shao et al (2001) illustrate a sphyraenid egg (pg 141) which is similar in appearance, though smaller at 780µm (but note that use of circular lighting has created a ring around the oil globule in their photograph). Their yolksac larva is also similar, with a very similar yellow pigment pattern. October 2011 update; a match has been found with adult Sphyraena obtusata in BOLD, a species known from South Africa and Japan (Senou, 2001).

This egg is rare at Park Rynie, having been seen only 4 times, once in May, once in June, and twice in September. Thus no graphics are presented. On each occasion there were 2-3eggs in the sample. Six of the 11 eggs were in inshore samples.