Monotaxis grandoculis, the Humpnose big-eye bream, is a species of emperor native to the Indian Ocean and the Pacific Ocean to the Hawaiian Islands. Small juveniles are whitish silver on the lower half of the body with three prominent black saddles with white in between on the upper half. A vertical black line crosses the eye from above. The small juveniles have yellow stripes on the tail. As the juveniles grow so the body rounds out as can be seen below and the yellow on the tail disappears.
Adult humpnose Big-eye Bream are bluish-grey above and silvery on the sides. The fins are reddish-orange and the area around the eye is often yellow. Adults are usually seen without any markings, but can quickly assume four broad blackish bars or saddles on the body. Juveniles have three black saddles separated by white bars on the upper half of the body. They have a prominent black bar through the eye. Juvenile colouration can be seen in individuals up to 30 cm in length. The species grows to 60 cm in length.
Humpnose big-eye bream's facts
Did you know?
It is currently the only known member of its genus (monotaxis).
Humpnose big-eye bream's Behavior & Ecology
As adults this fish often forms large aggregations of up to 50 individuals, but solitary fish have been observed. Juveniles are usually solitary.
Colour changes from no stripes to stripes when disturbed.
The fish inhabits areas with sand or rubble adjacent to coral reefs at depths from 1 to 100 meters but can mostly be found between 5 to 30 meters.
Humpnose big-eye bream's Feeding
The Humpnose Big-eye Bream is a nocturnal feeder. Food items include molluscs, brittle stars, sea urchins, crabs, polychaetes, sea squirts and sea cucumbers.
Humpnose big-eye bream's Reproduction
The exact method of reproduction of the humpnose big eye bream is not known. It is thought that the males initiate the females to drop their eggs into the water table from a shallow depth and that they then release sperm into the water, fertilizing the eggs.
Humpnose big-eye bream's Conservation
It is currently categorized as ‘Least Concern’ by IUCN.
Humpnose big-eye bream's Relationship with Humans
This species is commercially important as a food fish.
Humpnose big-eye bream habitat
Monotaxis grandoculis is usually found on coral reefs, often on the sandy periphery or in sand and rubble areas. Solitary individuals are often encountered, but large adults frequently form aggregations of up to about 50 individuals. The depths range of this species is between 3 and 60 m, although it appears to be most common between about 5 to 30 m. This species consumes mainly gastropod molluscs, ophiuroids and echinoids as well as pagurid and brachyuran crabs, polychaetes, tunicates and holothurians. It reaches a maximum size of 60 cm total length (TL); however, it is commonly seen to 40 cm TL (Carpenter 2001).
Humpnose big-eye bream threats
This species is fished throughout its range, but this does not currently appear to be a major threat at the global level.