Acanthuridae: L III E7

Acanthurus mata Cuvier, 1829.

Elongate surgeon

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
670-720	1	160-180	clear	narrow	stern	42% of NL	23

Egg: The oil globule is large relative to egg diameter. Tiny yellow pigment spots develop on the embryo, mostly from mid-tail to mid-thorax, and behind the eyes. They are most dense on the thorax. Yellow pigment also appears on the oil globule. The oil globule is clear to pale amber. Incubation is ca. 24 hours. The eggs are seen fresh, or actively hatching, implying both morning and evening spawning.

Larva: The yolksac larva has white/yellow pigment behind the eyes and in a band over the yolksac (B). In the 1-day larva, this has formed a solid band from the eye to past the anus (C), which turns a golden yellow by days 3 to 4 (D). Note the exaggerated forehead and small mouth. The dorsal and ventral finfold edges are serrated posterior to the anus.  B: NH, C: 1 day, D: 3 days (26°C).

The small mouth on the 4-day larva probably accounts for the total failure of attempts to rear this larva on Brachionus. Eleven larvae have been sequenced, and they match 3 adult A. mata collected off Park Rynie (BOLD).

Linked samples	Offshore	Inshore
Eggs	5112	4022
Hits	61	74

This was the 14^th most common egg off Park Rynie, and clearly a summer spawner (blue graph). It was seen in the DHM samples on only 1 occasion, in January. The egg has become more common off Park Rynie in the latter half of the study (white graph). Park Rynie linked samples showed slightly more of these eggs offshore (56%), indicating spawning around the 30m contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.