Sky emperor, Mahsena emperor, Cutthroat emperor
Lethrinus mahsena, common names the sky emperor, mahsena emperor, and cutthroat emperor, is a species of emperor fish. It grows to 65 cm (26 in) in length, but is commonly found at between 35 and 45 cm (14 and 18 in). This fish may be yellow to greenish-blue or olive-grey, becoming paler toward the belly. It is a non-migratory, reef-associated fish that has a high commercial value.
Lethrinus mahsena has the specific name mahsena which is derived from the Arabic name for this fish in Saudi Arabia, Sjöûr mehseni.
Lethrinus mahsena has a body which may be yellow to greenish-blue or olive-grey, becoming paler toward the belly. It commonly has nine to ten vertical bars of colour that are yellow-green or brown and a horizontal yellow stripe lattice pattern. The base of the scales may be dark or even black. At the base of the pectoral fins, there is a red bar. It grows to a maximum length of 65 cm, but is commonly found at 35 to 45 cm.
The head is purplish-grey, occasionally with a red patch on the nape. It has a moderately short snout. The lips are a strong red colour. There is a red line running from the corner of the mouth toward the tail, and in some specimens there is a line of white or yellow colouration running forward from the eye through the nostrils.
The profile of the dorsal fin is almost straight to slightly concave.
The fins are generally reddish, especially toward the tips.
Lethrinus mahsena is known to live in the Red Sea, the waters of East Africa including the waters around Madagascar. It has also been recorded southern Japan, Polynesia, the Seychelles, Cebu, Philippines, the western Indian Ocean, and the waters of Sri Lanka.
Lethrinus mahsena is a non-migratory, reef-associated fish. It lives in waters ranging from 2 to 100 metres in depth. It is found in coral reefs and the adjacent sandy bottoms. It also lives in seagrass areas.
Lethrinus mahsena is known to feed on echinoderms (in particular, sea urchins), crustaceans, and otherfishes. It also eats molluscs, tunicates, sponges, polychaetes.
Lethrinus mahsena has according to the available data undergone a 60% population decline over three generation lengths, measured over the 45 years between 1973 and 2018. It is exploited as very high levels throughout the overwhelming majority of its distribution, and it is extrapolated that the limited available data indicates its global status and the IUCN has assessed this species as Endangered.
