Platycephalidae: L III A5

Cociella heemstrai Knapp, 1996

Spotfin flathead


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








50% of NL



Egg: My notes often describe this egg as pretty, due to the yellow pigment on the larva, oil globule and yolk (A). Black pigment is present, with the same distribution. The oil globule is light amber. Initially I had difficulty separating this egg from smaller eggs of LIIB5, but then noted that the black pigment spots on the yolk, appeared dark red on a white background, and have found this a reliable means of separation. Incubation is about 35 hours.

Larva: The NH larva looks much like LIIB5 and even FIIA9 (though the segmented yolk separates the latter egg), but quickly forms a diagonal through the body, posterior to which there is no yellow pigment (C, D & E). At 5 days, the tip of the lower jaw often bears a black spot. B: NH, C: 2 days, D: 3 days, E: 4 days, F: 32 days, (23-24°C).

This larva proved quite difficult to rear, but on one occasion a larva was taken through to 32 days before being sacrificed to provide a voucher specimen. Six larval sequences are available, matching the sequence of 5 adult C. heemstrai collected locally (BOLD).


Linked samples Offshore Inshore
Eggs 190 395
Hits 50 122

This was a common egg off Park Rynie, with spawning all year round (blue graph). It was also seen 6 times in the DHM samples (green graph). The occurrence of these eggs at Park Rynie, through the 25 years of sampling, has shown a steady presence, after initially perhaps being confused with LIIB5, but has recently been less frequently seen (white graph). The Park Rynie linked samples showed more of these eggs inshore (68%), indicating spawning around the 20m depth contour. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.