The plain brown fish that is everywhere and that nobody photographs. On many reefs it is the single most numerous fish present, and the reason the coral is not buried in algae.
Algal turf grows fast enough to smother a reef within weeks. Surgeonfish crop it continuously, and this species does it in roving groups of dozens - which is not sociability but tactics. Damselfish farm their own algal patches and defend them furiously against any single grazer; a group of twenty brown surgeonfish simply swamps the farmer, feeds through the territory and moves on. A lone fish gets driven out, a mob does not.
Each carries the family scalpel at the tail base, folded into a socket until needed.
Twenty-one centimeters (8 in) at most, brown, common, and structurally important. A reef where these disappear becomes an algal reef within a season, which is exactly what has happened in places where herbivores are fished out.
The genus.Acanthurus Forsskål 1775 - acanthus (thorn or spine) + oura (tail). ETYFish
plain brown body with fine blue lines, easy to overlook
yellow smudge at the base of the pectoral fin
folding blade on each side of the tail base
in loose grazing groups that sweep across the reef together
length up to 21 cm
Why it's threatened
There was no clear trend in mean biomass observed between fished and marine reserves in the central Philippines (Stockwell et al. 2009). There are no major threats known for this species.
Surgeonfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reef while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. The majority of surgeonfishes are exclusively found on coral reef habitat, and of these, approximately 80% are experiencing a greater than 30% loss of coral reef area and degradation of coral reef habitat quality across their distributions. However, more research is needed to understand the long-term effects of coral reef habitat loss and degradation on these species' populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that recruit into areas with live coral cover, especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats (Comeros-Raynal et al. 2012).
Threat classification from the IUCN Red List.
Comments
Please, sign in to leave a comment
Continue with a social account — yours will be created automatically.
