The largest sergeant here, twenty-four centimeters (9.5 in), and the one that lives where the waves break.
Surge is a habitat with few residents and few predators, and the fish built for it are heavy-bodied with strong pectoral fins - the same solution the surge wrasse arrived at. It grazes algae off rock, takes small invertebrates, and holds position in water that would push most reef fish off the crest.
Males nest in the same zone, on rock cleaned to bare stone, and guard eggs through conditions that would tear a nest apart anywhere less solid. A guarding male in surge is one of the more impressive sights on a reef flat: he does not leave the patch, whatever comes over it.
It is also one of the few reef fish that a snorkeler meets before a diver does, since the first two meters of water are where it lives and the last place anyone with a tank goes.
The genus. Abudefduf Forsskål 1775 - def (side). ETYFish
The species. Abudefduf sordidus (Forsskål 1775) - dirty. ETYFish
- heavy-bodied sergeant with dark bars and a black spot at the top of the tail base
- yellowish tinge on the back in adults
- in white water on the reef crest, rarely deeper than a few meters
- length up to 24 cm
Why it's threatened
This species is potentially threatened by exploitation in Hawaii, but this is not considered a major threat.
Threat classification from the IUCN Red List.
