Speckled Snapper

Lutjanus rivulatus, commonly referred to as the blubberlip snapper or Maori snapper, is a marine ray-finned fish that belongs to the Lutjanidae family. This species is indigenous to the 🌊 Indian Ocean and extends into the 🌊 Pacific Ocean. It was first described in 1828 by French zoologist Georges Cuvier as Diacope rivulata, with the type locality identified as Puducherry and Malabar in 🇮🇳 India, Java in 🇮🇩 Indonesia, and the 🌊 Red Sea. The specific epithet "rivulatus" signifies "marked by irregular streaks" or "scribbled," which aptly describes the fish's numerous wavy blue lines on its head.

Lutjanus rivulatus is characterized by a notably deep body, with a standard length marginally more than twice its depth at the deepest point. It features a steeply sloped forehead, moderately developed knob, and incision in the preopercle. The vomerine teeth are crescent-shaped, lacking rearward extensions, and the smooth tongue is devoid of teeth, complemented by thickened lips. The dorsal fin comprises 10 spines and 15-16 soft rays, while the anal fin consists of 3 spines and 8 soft rays. The dorsal fin exhibits a rounded rear profile, contrasting with the anal fin's sharply pointed shape. The pectoral fins contain 17 rays, and the caudal fin is typically truncate or weakly emarginate. This species can reach a maximum total length of 80 cm (31 in), with a more common length being 60 cm (24 in), and a recorded maximum weight of 11 kg (24 lb). The fish displays an overall brown hue with a reddish tint and prominent yellow coloring on the outer dorsal, anal, and caudal fins. The head showcases a pattern of blue lines, while finer blue dashes and dots adorn the body, along with a blurred dark bar over the base of the pectoral fin, which diminishes in visibility as the fish matures. Juveniles exhibit this bar along with 3-8 dark vertical bars and a white spot on the flanks.

Lutjanus rivulatus possesses a broad Indo-Pacific distribution, spanning from the eastern African coastline between the southern 🌊 Red Sea and 🇿🇦 South Africa to the 🌊 Pacific Ocean, reaching as far east as Tahiti and the Austral Islands (🇵🇫 French Polynesia), north to 🇯🇵 Japan, and south to 🇦🇺 Australia. In 🇦🇺 Australian waters, it is present from Port Hedland and offshore reefs in Western Australia, the Ashmore Reef in the Timor Sea, extending east and south to northern New South Wales, and is also found in the Coral Sea and at Christmas Island. The species inhabits depths ranging from 3 to 100 meters (4 ft 11 in to 328 ft 1 in) and is primarily associated with reefs. Adult specimens are typically found on deep coastal slopes, while juveniles inhabit flats with algal growths, often near freshwater discharges.

Lutjanus rivulatus can be found either as solitary individuals or in small groups consisting of 15-20 fish. Similar to other snappers, this species is predatory, feeding on fish, cephalopods, and benthic crustaceans. Sexual maturity is generally reached at approximately 50 cm (20 in) in length, although instances of maturity have been recorded at 37 cm (15 in). The species is known to form spawning aggregations. Despite its large size, it remains a wary fish.

Lutjanus rivulatus is highly regarded for its edible qualities, although its consumption has been associated with Ciguatera fish poisoning. It represents a significant species for artisanal fisheries across its range, typically captured using handlines, traps, and gillnets, though it is rarely trawled. Additionally, this species is included in the 🇭🇰 Hong Kong live fish trade and is cultivated in aquaculture within Southeast Asia.