Dusky parrotfish, Scarus niger, common names the swarthy parrotfish, and black parrotfish, is a species of parrotfish. It is in the phylum Chordata, class Actinopterygii and family Scaridae. Like other members of its family, it has characteristic 10 dorsal soft rays, 9 dorsal spines, 9 anal soft rays, and 3 anal spines, It is found in Indo-West and Central Pacific, from the Red Sea, north to Japan, south to Austarlia and east to French Polynesia. It is found in lagoons, channels and outer reefs slopes on the depths of 2 to 20 metres (6 ft 7 in to 65 ft 7 in).
The dusky parrotfish often lives in solitude, but males may also live in a small group of mating females. The dusky parrotfish is primarily herbivorous, and its main source of food is benthic algae. At maturity, the fish is approximately 230-240mm long and weighs around 240g. pesce pappagallo scuro.

Dusky parrotfish – Pesce Pappagallo scuro – Scarus niger – www.intotheblue.it – www.intotheblue.link
Dusky Parrotfish is a protogynous hermaphrodite, as evidenced by instances where a dominant female in a group with only females turned into a male. The dusky parrotfish is oviparous, so when breeding, the male and female fishes form pairs and the female lays eggs that later hatch. Marine herbivores like the swarthy parrotfish rely on endosymbiotic microorganisms to digest carbohydrates.
In aerobic conditions, bacteria ferments the carbohydrates and produces short-chain fatty acids or SCFAs. First studied in vertebrate herbivores, SCFAs also allow marine herbivores to further digest carbohydrates that were not broken down by digestive enzymes.

Dusky parrotfish – Pesce Pappagallo scuro – Scarus niger – www.intotheblue.it – www.intotheblue.link
The presence of the swarthy parrotfish in large and small reef communities contributes to diversity and therefore the resilience of the ecosystem. The reef ecosystem may be dramatically shifted in the absence of the swarthy parrotfish. After extreme climate events, like cyclones, subtle reef dynamics change such as grazing by herbivorous fish. In 2011-2012, after severe climate disturbances, grazing by herbivorous fish, including the swarthy parrotfish, decreased by over 90%. Although these changes were not visible, they make the reef ecosystem highly unstable, and many reefs may be on the verge of collapse. The reductions in grazing can cause algal turfs, which are non-palpable to the swarthy parrotfish.

Dusky parrotfish – Pesce Pappagallo scuro – Scarus niger – www.intotheblue.it – www.intotheblue.link
Dusky Parrotfish are widely distributed, but mainly scattered around the Indo-Pacific region. Dusky parrotfishes inhabit areas of the reef that are coral-rich such as the reef flat and reef slope. The swarthy parrotfish is not heavily fished and therefore their population dynamics are more likely determined by habitat and recruitment.
(extract from Wikipedia)
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