Scombridae: L III A11A

Euthynnus affinis (Cantor, 1849).

Eastern little tuna.


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








42% of NL



Egg: This egg is easily comnfused with some of the small carangids (EIIIA6) when seen in the stage shown in Plate A. The confusion arises because the oil globule is not always distinctly tucked under the tail of the developing larva. But a check for a clear yolk, and the time of year, will distinguish this egg. It was also sometimes confused with sparids such as Pachymetopon grande (LIIIB10), but this too is more typically a winter spawner. Incubation is about 30 hours.

Larva: The early larva has a characteristic pattern of yellow (B), and a high myomere count, which immediately identifies this species from all but the other two summer spawning scombrids A. rochei (LIIIA11) and Katsuwonus (LIIIA11B).  By day 4, all yellow pigment had disappeared (C). B: NH, C: 3 days (25-26°C).

Nine larvae from eggs have been barcoded, matching four locally collected adults (BOLD).


Linked samples Offshore Inshore
Eggs 113 240
Hits 14 12

This egg was not often seen (or recognised) off Park Rynie, and may have been combined with LIIIA11 in the past. Eggs were only recorded in summer (blue graph), which is when this fish is most abundant in the Park Rynie area. It was not seen in the DHM samples. It has occasionally been quite abundant, with years of total absence (white graph). The Park Rynie linked samples showed most eggs inshore (68%), but this is based on low numbers. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.