Stromateidae: F II A5

Centrolophus niger (Gmelin, 1789).

Black ruff

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
1200-1345	1	340-410	segmented	narrow	stern	52% of NL	25

Egg: When seen within 24 hours of development, the light amber oil globule is apparent, and the embryo, oil globule and yolk are dotted with black pigment, with just a few pale yellow spots on the larva. At 48 hours, the larva has 7-8 yellow and black blotches that make the egg unmistakable in its size range. Incubation is about 70 hours (21°C).

Larva: The newly hatched larva has a yellow pigment pattern that is instantly recognisable (B & C), with almost no black pigment visible, but on a white background, black pigment shows the same pattern as yellow pigment.  By day 6 some yellow/brown pigment has moved into the finfolds (E), which persists through days 11 to 18 (F & G). At 11 days the larva is undergoing flexion (F), and by 18 days, flexion is complete (G).  B: 1 day, C: 2 days, D: 3 days, E: 6 days, F: 11 days, G: 18 days (21°C).

This species was not reared past 18 days. The identification is based on DNA of 8 larvae, matching several adult C. niger sequence in BOLD, from New Zealand and Australia. No locally collected adults have been sequenced.

Linked samples	Offshore	Inshore
Eggs	910	91
Hits	79	42

This species is a winter spawner, and the appearance of these striking eggs in early winter samples is an event, like a “birder” seeing the first winter migrant. The annual pattern of egg collection at Park Rynie (white graph), suggests an increase in eggs during the past 10 years, but it is probably not significant, being based on just 3 above average years. The Park Rynie linked samples had 91% offshore, which is consistent with their being oceanic drift fishes (Haedrich 1986). See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.