Description:

Dorsal spines: 13-14; Dorsal rays: 10; Anal spines: 7; Anal rays: 9-10;

Oval-bodied strongly compressed fish varies considerably in colour pattern depending on the mood of the fish and the colour of its habitat. Upper body greenish to sandy brown, silver grey below with pale spots evenly spaced on sides Top of head and dorsal fin yellowish. Yellow iris. Often displays dark blotch at origin of lateral line.  Caudal fin concave. When viewed underwater this fish may lack any markings and be uniformly olive brown. Frightened fish marbled light and dark brown, obscuring large spots, often in the form of six irregular, dark diagonal zones.

Size:

Maturity: Lm unknown. Range: males 21.7 - ?cm TL, females 22.8 - ?cm TL. Max Length: 45cm TL. Common length 30cm.

Habitat and Ecology:

Inhabits seagrass beds and rocky/coral reefs (depth 1-50m, but typically 1-12m). A browser its vegetarian diet consists primarily of filamentous seaweeds and eel grasses. It forms schools. It is a short-lived (2.5 yrs), fast-growing, gonochorist and herbivorous reef species (Grandcourt 2002, Bijoux et al. 2013). In the Seychelles, S. sutor forms monthly transient spawning aggregations between September and June around the full moon (Bijoux et al. 2013). 

Fishery Status:

This species is not protected or subject to fishery regulations. It is caught in the fish trap fishery, and is a common and often abundant component of the catch. It is particularly abundant when its seasonal spawning aggregations are targeted.

The Praslin Fishers Association (PFA) have recognised the economic importance of the S. sutor fishery and have proposed various restrictions on the fishery to safeguard its sustainability around the island group. Unfortunately these proposals though endorsed have yet to be promulgated by the authorities. 

Notes:

Spines venomous. 

References:

Bijoux, J.P. et al 2013. Temporal dynamics, residency and site fidelity of spawning aggregations of a herbivorous tropical reef fish Siganus sutor. Marine Ecology Progress Series 475(1): 233-247.

Froese, R. & D. Pauly. Eds. 2018. FishBase. https://www.fishbase.de/summary/Siganus-sutor (19/03/19).

Grandcourt, E.M. 2002. Demographic characteristics of a selection of exploited reef fish from the Seychelles: preliminary study.

Heemstra P & Heemstra, E. (2004). Coastal Fishes of Southern Africa. NISC SAIAB. ISBN: 1-920033-01-7.

Nevill, J. (2013). A Species Identification Guide for Commonly Caught Fish in the Seychelles Near-Shore Artisanal Fishery. GOS/UNDP/GEF.

Smith, M & Heemstra, P Eds. (1999). Smiths’ Sea Fishes Edition 6. Springer-Verlag Berlin Heidelberg 10.1007/978-3-642-82858-4

Van Der Elst, R. (2012). A Guide to the Common Sea Fishes of Southern Africa. Struik Nature, Cape Town, South Africa. ISBN: 978 1 86825 394 4

Yahya, S. et al 2018. Siganus sutor. The IUCN Red List 2018: e.T117007332A117008798. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T117007332A117008798.en.(20/03/19).

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