Ophidiidae: K III A6

Brotula multibarbata Temminck & Schlegel, 1846

Bearded brotula

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
730-1080	1	155-200	clear	narrow	bow	38% of NL	ca42

Egg:. This egg is usually easy to recognise because it is not quite round (but not symmetrically oval), has no pigment on the embryo or oil globule, and has a red sheen to the chorion. The oil globule is clear. Just before hatching some fine black pigment dots may be seen on the embryo. Incubation is about 48 hours.

Larva: The early larva has clear finfolds, which are goose-pimpled (C). Scattered fine black pigment is seen, in a pattern similar to Plate C1. At 6 days big pectorals have a pale yellow edge, there is a loose cluster of black dots across the notochord in mid-tail, and often, a dark patch above this on the edge of the finfold (D, arrowed, best seen in the bottom specimen). When disturbed, the eyed larvae curl the body in a sharp bend at the trunk, while most of the tail remains straight. B: NH, C: 1 day, D: 6 days (23°C).

All attempts to rear this egg were unsuccessful. There may be two (or more) species included here, as sometimes the egg appears more symmetrically oval. The wide size range supports this. Care should be taken not to confuse them with BLIIIA1 & BLIIIA2, the eggs of which are regularly oval, larvae have far fewer myomeres, and the oil globule is astern in the NH larva.Six hatched larvae have been barcoded, 4 of which match the sequence of 2 adult B. multibarbata collected locally. The other 2 larvae, however, indicate 2 further species, which have not found a match in the adult barcodes.

The odd egg shape may be due to the eggs initially being laid in a gelatinous mass (Mito 1962).

The all-year presence of this egg off Park Rynie also suggests the possibility of more than one species, although there is a definite summer peak (blue graph). The egg was only seen twice in the DHM samples, in March and July. At Park Rynie, the egg has shown an increasing presence (white graph). In the Park Rynie linked samples, the eggs were marginally more common offshore (58%), suggesting a species that is spawning inside the 30m contour.  See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.

Linked samples	Offshore	Inshore
Eggs	585	427
Hits	66	59