Onespot Snapper

Lutjanus monostigma, commonly known as the one-spot snapper, onespot seaperch, or Moses snapper, is a marine ray-finned fish species belonging to the family Lutjanidae. This species is prevalent throughout the Indo-Pacific region.

Originally described in 1828 by the French zoologist Georges Cuvier as Mesoprion monostigma, the type locality for Lutjanus monostigma was designated as the 🇸🇨 Seychelles. The specific epithet "monostigma" is derived from the Greek, with "mono" meaning "one" and "stigma" meaning "mark," in reference to the distinctive black spot located beneath the anterior dorsal fin rays. This characteristic is prominent in juvenile specimens, though it tends to fade in many adults.

Lutjanus monostigma is characterized by a relatively deep body, with a standard length that is 2.6 to 3.0 times its greatest body depth. It features a gently sloped forehead, and the preopercular incision and knob are only weakly developed. The vomerine teeth are arranged in a crescent-shaped patch without a central rearward extension, and the tongue lacks teeth. The dorsal fin contains 10 spines and 13 to 14 soft rays, while the anal fin has 3 spines and 8 to 9 soft rays. The posterior edges of both the dorsal and anal fins are rounded or angular in shape. The pectoral fins possess 15 to 17 rays, and the caudal fin is either truncate or weakly emarginate. This species can reach a maximum total length of 60 cm (24 inches), although lengths of around 50 cm (20 inches) are more prevalent. The coloration of Lutjanus monostigma varies from whitish to pink or grey, with yellow fins and a black spot located posteriorly on the body, which becomes more oblong as the fish matures.

The geographic distribution of Lutjanus monostigma extends from the eastern coast of Africa, including the 🌊 Red Sea and southward to Sodwana Bay in 🇿🇦 South Africa. It is also present in the 🌊 Persian Gulf and throughout the 🌊 Indian Ocean islands, southeastern 🇮🇳 India, 🇱🇰 Sri Lanka, Southeast Asia, and extends eastward to the Marquesas and Line Islands, northward to the Ryukyu Islands (🇯🇵 Japan) in southern 🇯🇵 Japan, and southward to 🇦🇺 Australia. Mature individuals inhabit coral reef environments, typically near caves and coral formations, at depths ranging from 1 to 60 meters.

Lutjanus monostigma is a nocturnal predator, primarily preying on fish and benthic crustaceans. While often encountered as solitary individuals, they occasionally form small schools. In the waters off Papua 🇵🇬 New Guinea, it is estimated that 50% of females reach sexual maturity at a length of 32 cm (13 inches) and approximately three years of age. This moderately sized snapper is believed to have a maximum lifespan of 13 years.

This species holds significant commercial value in many regions where it is found, particularly throughout Oceania. The catch is predominantly marketed as fresh fish, employing methods such as handlines, traps, and gillnets. It is noteworthy that Lutjanus monostigma is associated with ciguatoxicity, especially in regions like Tuvalu. Despite its broad distribution, the species appears to thrive in areas with minimal fishing pressure, maintaining robust populations. Consequently, the International Union for Conservation of Nature (IUCN) has classified it as Least Concern.