Take the parrotfish off a reef and the reef turns into a lawn.
Coral and algae are in permanent competition for the same hard ground, and algae grow far faster. What keeps them in check is grazing, and on most tropical reefs the heavy lifting is done by parrotfish and surgeonfish working every surface all day. Remove them - and parrotfish are heavily fished across much of their range, being large, slow, and easy to spear at night in their cocoons - and the algae take over within a few seasons. Coral larvae cannot settle on an algal mat, so the reef stops replacing itself.
That has been demonstrated the hard way in the Caribbean, where the loss of large grazers turned coral reefs into algal beds over about two decades, and it is the main argument for protecting a fish that is otherwise unremarkable to look at.
This one is a mid-sized shallow-water species, green in terminal males with a blue-green beak, and plain gray-brown in the initial phase. It works reef flats and shallow coral, and it is doing the same job as all of them: eating the competition, one scraped mouthful at a time.
The genus.Scarus Forsskål 1775 - skaros (ancient Greek name of Sparisoma cretense). ETYFish
The species.Scarus viridifucatus (Smith 1956) - viridis (green) + fucatus (painted or colored). ETYFish
How to recognise it
terminal males green with a blue-green beak and dark-edged scales
initial-phase fish gray-brown, plain
shallow water, mostly above fifteen meters
up to 45 cm
Why it's threatened
Scarus viridifucatus is harvested throughout most of its range, as a food source. It is harvested using artisinal fishing gear such as nets and traps. There is no current evidence to suggest that this is causing a significant decline in the global population.
Due to this species association with coral reef habitats it is likely to be undergoing declines due to threats on its habitat including destructive fishing practices, coral bleaching, Crown of Thorns starfish invasions, coastal development, pollution, and tourism. However these are localised threats and not considered a major threat to this wide ranging species.
Parrotfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reefs, while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. Although the majority of the parrotfishes occur in mixed habitat (primarily inhabiting seagrass beds, mangroves, and rocky reefs) approximately 78% of these mixed habitat species are experiencing greater than 30% loss of coral reef area and habitat quality across their distributions. Of those species that occur exclusively in coral reef habitat, more than 80% are experiencing a greater than 30% of coral reef loss and degradation across their distributions. However, more research is needed to understand the long-term effects of habitat loss and degradation on these species populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that depend on live coral reefs for food and shelter 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. Furthermore, coral reef loss and declining habitat conditions are particularly worrying for some corallivorous excavating parrotfishes that play major roles in reef dynamics and sedimentation (Comeros-Raynal et al. 2012).
Threat classification from the IUCN Red List.
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