Mullidae: E III B1

Upeneus guttatus (Day, 1868).

Twotone goatfish.

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








33% of NL


Egg: Two rows of stellate black pigment dots run down the length of the embryo. Black pigment is dense on the oil globule ventrally, and gets magnified through the clear oil globule, making the oil globule look black when viewed from above, through the microscope. There are a few pigment spots scattered on the yolk near the embryo. (A1). The PVS is wide for a perciform, and segmentation of the yolk is unusual in that it often comprises one segment running parallel to the yolk edge, just inside the edge. The oil globule is often not round, but elongated when viewed from the side. Incubation is about 24 hours.

Larva: The NH larva (B) can show this extreme protrusion of the oil globule, but it rapidly moves to the more conventional (C), at which stage black pigment is scattered on the notochord.  At 3-4 days, the black pigment has consolidated over the gut (D, E & F), with a spaced line of black pigment dots ventrally, along the notochord to its tip (F). At this stage the larva often displays a metallic blue sheen on the eyes and gut (F). B: NH, C: 1 day, D: 3 days, E & F: 4 days (24-25°C).

This species shows strong affinities to KIIIA10, except for the segmented yolk and shorter body. Eight hatched larvae have been barcoded, and match the barcodes of 2 juvenile mullids taken by handnet at the surface off Park Rynie in December 2005. All match the barcode of 5 adult U. guttatus collected locally (BOLD). A single egg under this code, collected in May 2011, has barcode-matched a single Lethrinus olivaceus adult collected off Park Rynie (BOLD).

Ikeda & Mito (1988) illustrate mullid eggs of different species, some with, and others without a segmented yolk.

This was a common egg off Park Rynie with just over 2000 seen during the study (Table 3; Introductory Notes). They were seen all year round (blue graph). They were also represented in the DHM samples (green graph), but again, showed no particular seasonality to spawning. The annual catch (white graph) initially shows a confused pattern, but has recently been more consistent. The linked samples revealed 66% inshore, suggesting the species is spawning in 20-30m water depth. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.

Linked samples