Chaetodontidae: L III E8

Heniochus acuminatus Linnaeus, 1758.

Coachman

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
690-745	1	170	clear	narrow	stern	55% of NL	24

Egg: The oil globule is bright golden amber. The oil globule is larger, relative to egg diameter, than LIIIE4 and LIIIE5, allowing early separation of this egg. The egg has a white appearance, due to white pigment in the developing embryo. Incubation is 24-28 hours. In one batch the yolk was noted to be segmented around the edge.

Larva: The 1-day larva has white pigment from behind the eyes, in a band over the yolksac to past the anus (B). In the 2-day larva, the white pigment has moved up over the notochord in a curious, chaotic pattern, interspersed with black spots, and a blush of red-brown over the notochord from oil globule to anus (C). The dorsal and ventral finfolds are peppered with fine black spots (C1). By day 4, the white pigment has formed two saddles over the notochord, with a longer black patch between (D). B: 1 day, C: 2 days, D: 4 days (26°C).

The fine black spots in the finfolds, and general appearance suggested this was a chaetodontid. Five larvae have been barcoded; 4 matched 2 adult Heniochus acuminatus collected locally. The fifth matched Heniochus diphreutes (BOLD). One of the larvae in E is H. diphretes the other is H. acuminatus; I do not know which.

Linked samples	Offshore	Inshore
Eggs	310	40
Hits	16	13

Uncommon off Park Rynie, but catches indicate a summer spawner (blue graph). Not seen

in the DHM samples. Park Rynie linked samples had most eggs offshore, and although

biased by two big catches, of 43 (December 1997) and 150 eggs (December 2002),

catches in the past 5 years have maintained an 80% offshore distribution. Thus while

divers see this fish on 30m reefs in the area, the egg data suggests it occurs in

water depths well in excess of 50m. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the

linked samples.