Scarus vetula

Scarus trispinosus range from the West Indies to Florida. (Breder, 1929)

Scarus trispinosus are found in the tropical coral reefs of the Caribbean and are, therefore, restricted to relatively shallow water (Boschung, 1983).

Scarus trispinosus have four rows of scales on their cheeks. They have no longitudinal band on their head or body, but a red band near the edge of the caudal fin is present (Breder, 1929). S. trispinosus have teeth that form beak-like plates, similar to parrots. The lower plate is hidden by the upper plate when their mouth is closed. S. trispinosus can be identified by a long, single dorsal fin and a truncated caudal fin (Boschung, 1983). S. trispinosus exhibit sexual dimorphism, females are a drab bluish-brown, with a pale band running along the lower side of the fish, males are green-blue, with scales that have yellow centers and distinct yellow lines running from the mouth to the eye (Wheeler, 1975). S. trispinosus young have two white stripes and a white belly (Smith, 1997).

Scarus trispinosus reproduce sexually with external fertilization. Breeding occurs throughout the year, with most activity in the mornings. Their breeding system is characterized as harem polygyny: one male mates with multiple females. The supermale in the group is in a terminal phase, where he is brightly colored. The supermale spawns with an individual female by first swimming in circles around the females and then as they increase their speed and tighten their circles the female joins the supermale. At this time the gametes are released into the water (Clavijo, 1983). Other males spawn with females in groups (Smith, 1997). S. trispinosus have both an egg and a larval stage and a primary and a terminal phase where they change colors (Lowe-McConnell, 1987).

Scarus trispinosus are mostly found in small schools of 3 - 4 females and a supermale. They are not strong swimmers so they scull themselves along with their pectoral fins (Lythgoe, 1992). S. trispinosus are only active during the day. During the night they find a crevice to sleep in and then they secrete a mucous envelope around themselves for protection (Wheeler, 1975).

Scarus trispinosus are active diurnal herbivores. They scrape algae, preferably turf algae, that is on flat surfaces and coral from coral reefs with their unique beak (Bruggemann, 1994). S. trispinosus crushes the coral and algae mixture finely in the pharyngeal mill, and the indigestible sand is excreted (Wheeler, 1975). It has also been found that S. trispinosus feeds on sponges (Dunlap, 1998).

Scarus trispinosus are a large contributor to the production of sand through their digestion of corals. They are also believed to be a major reef attraction (Wheeler, 1975).

Scarus trispinosus have become one of the most important biological factors in the erosion of coral reefs. They also effect the distribution and abundance of Caribbean sponges by feeding on them (Dunlap, 1998). The decrease of coral reefs and sponges have caused a decrease in the tourist industry's revenues (Wheeler, 1975).

Scarus trispinosus are not endangered.