Awaous commersoni (Schneider, 1801)
Commerson’s freshwater goby

Family:  Gobiidae (Gobies), subfamily: Gobionellinae
Max. size:  25 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater; brackish, amphidromous
Distribution:  Southwestern Indian Ocean: RĂ©union, Mauritius, Rodrigues, Comores, Madagascar.
Diagnosis:  Dorsal spines (total): 7-7; Dorsal soft rays (total): 10-11; Anal spines: 1-1; Anal soft rays: 9-10. Large head. Fusiform body. Large and terminal mouth. Two dorsal fins. First with 6 spines, second with 1 spine and 10 to 11 branched rays. Adults body and fins usually grey to black with a clearer belly. Juveniles brown with a serie of darker rounded marks along the flanks. First dorsal usually shows a black mark in its posterior part, especially for young specimens. Fading while fish age. 10 to 25cm (Ref. 57749).
Biology:  This species occurs in freshwaters and sometimes brackish waters in slow to fast current waters to the base of the first falls. Usually occurs in clear waters with sand, gravel or rock bottom. Feeds on algae, detritus, worms, gastropods and crustaceans. Close biology to A. guamensis. Amphidromous species. Adults migrate to the mouth of the rivers for reproduction. Females spawn on the rocks' surface where the males fecund the eggs. Males protect the eggs until they hatch (incubation lasts 24 to 70hrs). Larvae, translucid, are then carried into estuaries or sea. They come back after they spent 150 to 165 days in seawaters (Ref. 57749). Also Ref. 4343.
IUCN Red List Status: Vulnerable (VU); Date assessed: 25 June 2018 (B1ab(iii)+2ab(iii)) Ref. (130435)
Threat to humans:  harmless


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