Yellowlined Fusilier

Caesio varilineata, commonly known as the variable-lined fusilier or thin-lined fusilier, is a pelagic marine ray-finned fish belonging to the family Caesionidae. This species is predominantly found in the Indo-Pacific region, inhabiting depths ranging from 2 to 25 meters.

The species was formally described in 1987 by American ichthyologist Kent E. Carpenter, with its type locality identified as the 🌊 Persian Gulf. Carpenter assigned it to the subgenus Caesio. The specific name, "varilineata," is derived from the Latin terms "vari-" meaning "various," and "lineata," meaning "lined." This nomenclature refers to the species' distinctive variable number of horizontal golden stripes on its sides.

Caesio varilineata is a small to medium-sized fish, capable of reaching a maximum total length of 40 cm (16 inches). It is characterized by large eyes, a small terminal mouth that is capable of being extended for feeding, and a fusiform, or spindle-shaped, body. The caudal fin is deeply forked. The dorsal fin comprises 10 spines and 14-16 soft rays, while the anal fin contains 3 spines and 11-13 soft rays. The body displays a silver green-blue coloration accented by 2 to 6 yellow longitudinal lines of variable intensity and width. A distinctive black line marks the external part of the lobes of the caudal fin.

Geographically, C. varilineata is confined to the 🌊 Indian Ocean, extending from western 🇮🇩 Indonesia to the eastern coast of Africa, including the 🌊 Red Sea and 🌊 Persian Gulf. It resides in open water adjacent to reefs. Recent reports have documented its presence in the Mediterranean Sea near Alexandria, 🇪🇬 Egypt, suggesting a probable migration through the Suez Canal (🇪🇬 Egypt). In the absence of coral reefs in the Mediterranean, these fusiliers have likely adapted to rock reefs covered with Anthozoa.

The diet of C. varilineata primarily consists of zooplankton, which it consumes in aggregations within the water column. It often forms mixed-species schools with other fusilier species. This species is oviparous, producing a large number of small pelagic eggs.

In terms of economic significance, C. varilineata holds moderate importance for some coastal fisheries within its distribution range and only minor importance in others. It is typically captured using gillnets, handlines, and traps, and is sold fresh in fish markets, particularly in East Africa and 🇱🇰 Sri Lanka. In contrast, it is less frequently reported from markets in 🇴🇲 Oman, possibly as bycatch. In regions like the 🇲🇻 Maldives and Laccadive Islands (🇮🇳 India), juvenile specimens are collected for bait in the tuna fishery. However, the species is susceptible to overexploitation and is considered overfished in the 🌊 Persian Gulf. Notably, records from the Mediterranean were sourced from fish markets in Alexandria.