Hook-nosed sea snake, Common sea snake, Valakadyn sea snake, Valakadeyan sea snake
Enhydrina schistosa, commonly known as the beaked sea snake, hook-nosed sea snake, common sea snake, or the Valakadeyan sea snake, is a highly venomous species of sea snake common throughout the tropical Indo-Pacific. This species is implicated in more than 50% of all bites caused by sea snakes, as well as the majority of envenomings and fatalities.
The Beaked sea snake is a highly venomous species of sea snake common throughout the tropical Indo-Pacific. It is usually uniformly dark grey above; sides and lower parts are whitish. Young specimens are olive or grey with black transverse bands, broadest in the middle.
Beaked sea snakes are found in the Arabian Sea and Persian Gulf (off Oman), south of the Seychelles and Madagascar, the seas off South Asia (Pakistan, India, and Bangladesh), Southeast Asia (Myanmar (formerly Burma), Thailand, Vietnam). These snakes are generally found in shallow waters with muddy or sandy bottoms, estuaries, river mouths, and coastal lagoons and islands.
Beaked sea snakes are active both during the day and at night. They are able to dive up to 100 m and stay underwater for a maximum of five hours before resurfacing. Sea snakes are equipped with glands to eliminate excess salt. They are venomous and notably aggressive, with some herpetologists describing them as "cantankerous and savage". About 1.5 milligrams of their venom is estimated to be lethal.
The venom of this species is made up of highly potent neurotoxins and myotoxins. This widespread species is responsible for the vast majority of deaths from sea snake bites (up to 90% of all sea snake bites). The LD50 value is 0.1125 mg/kg based on toxicology studies. The average venom yield per bite is approximately 7.9–9.0 mg, while the lethal human dose is estimated to be 1.5 mg.
Beaked sea snakes are carnivores (piscivores) and feed exclusively on fish.
Beaked sea snakes give birth to a large number of live young that can reach 30 or even more. Young snakes usually spend 6-12 months in the shallow water before they are ready to leave out to sea. Reproductive maturity is reached at around 18 months of age and females usually give birth to the first clutch of young when they are around 24 months old.
The main threats to Beaked sea snakes include pollution, entanglement in fishing nets, and collection for their venom and skins.
According to IUCN, the Beaked sea snake is common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
