Synanceia

Synanceia is a genus of ray-finned fish belonging to the subfamily Synanceiinae, commonly known as the stonefish, which is classified within the family Scorpaenidae, the scorpionfish and close relatives. Stonefish are the most venomous fish known; stings can be fatal to humans. They are found in the coastal regions of the Indo-Pacific. They are sometimes confused with the freshwater lionfish.

Taxonomy Synanceia was first described as a genus in 1801 by the German naturalists Marcus Elieser Bloch and Johann Gottlob Theaenus Schneider with Scorpaena horrida, which had been described by Carl Linnaeus in 1766 from Ambon Island (Indonesia), as its type species. The genus Synanceia is classified within the tribe Synanceiini which is one of three tribes in the subfamily Synanceeinae within the family Scorpaenidae. Despite this, other authorities regard Synanceiidae as a valid family and the Synanceiini as the subfamily Synanceiinae. The genus name Synanceia is made up of syn 'with' and angeíon 'cavity', an allusion to the large, cavernous heads of the species considered to be in the genus.

Species

Synanceia contains the following species: Image Scientific name Common name Distribution Synanceia alula (Eschmeyer & Rama Rao, 1973) Midget stonefish northern Indian Ocean to the Solomon Islands Synanceia horrida (Linnaeus, 1766)Estuarine stonefish India to China, the Philippines, Papua New Guinea and Australia, and is also recorded in Vanuatu Synanceia nana (Eschmeyer & Rama Rao, 1973) Red Sea stonefish Red Sea and Persian Gulf Synanceia platyrhyncha (Bleeker, 1874) Indonesia Synanceia verrucosa (Bloch and J. G. Schneider, 1801)Reef stonefish Red Sea and Indo-Pacific Synanceia quinque Matsunuma, Manjaji‑Matsumoto & Motomura, 2021 Indonesia

Habitat and characteristics Synanceia are primarily marine, and although some species are known to live in rivers, most live in coral reefs near the tropical Pacific and Indian oceans. The species has potent neurotoxins secreted from glands at the base of their needle-like dorsal fin spines which stick up when disturbed or threatened. The vernacular name of the species, the stonefish, derives from its grey and mottled camouflage similar to the color of a stone.Pocock, C.A. "Romancing the Reef: history, heritage and the hyper-real." James Cook University Ph.D. Thesis. 2003. Accessed 2009-06-14. Swimmers may not notice them and inadvertently step on them, triggering a sting. When the stonefish is disturbed, it may inject an amount of venom proportional to the amount of pressure applied to it. Stonefish have the ability to extend sharp, specialized spines (lachrymal saber) as an additional defense mechanism.

Venom The venom of Synanceia consists of a proteinaceous toxin called verrucotoxin (VTX), which modulates Ca2+ channel activity through the β-adrenoceptor-cAMP-PKA pathway. In humans, stings can cause intense pain, respiratory weakness, damage to the cardiovascular system, convulsions and paralysis; sometimes they can lead to death. The exact mechanism is not yet fully understood.

Treatment of envenomation

Stonefish stings are injuries which may include envenomation and mechanical trauma. They are extremely painful and potentially lethal.Rebecca, Sarah. "The Most Excruciating Pain Known To Man." Scienceray. (29 Dec 2010): 1. Print. . There are a number of species of venomous fish including the stonefish. The two most recommended treatments are the application of heat to the affected area and antivenom. Hot water (at a temperature of at least ) applied to the injured area has been found to denature stonefish venom, and causes minimal discomfort to the victim. Antivenom is used in more extreme cases. Vinegar is found on some Australian beaches as it is said to lessen the pain.

Stonefish stings in Australia The stonefish is the most venomous known fish in the worldStonefish Envenomation, adventure medicine and stings can cause death if not treated.Marine Envenomation, Hornbeak, Kirsten B., and Paul S. Auerbach. Emergency Medicine Clinics 35.2 (2017): 321–337. Most stonefish stings occur as a result of stepping on the creature which forces venom into the foot, while it is less common for the fish to sting when it is picked up. Stonefish stings can occur on the beach, not just in the water, since stonefish can survive out of the water for up to 24 hours. They are not easily seen as they look similar to rocks or coral. Stonefish antivenom is the second-most administered in Australia.Stone Fish slk320

Some Aboriginal Australians have corroborees which involve reenacting the death of someone who trod on the fish. The aboriginal people of Northern Australia and the Great Barrier Reef have ways of preparing the fish for eating to avoid poisoning.The Poisonous Stone Fish Dreaded Denizen of the North The Argus 14 March 1936

After stonefish envenomation, the amount of anti-venom given depends on the number of puncture wounds from the stonefish spines.Stonefish antivenom product information

Number of incidents

There were 25 cases of the use of antivenom for stonefish reported to Commonwealth Serum Laboratories for a one-year period between July 1989 and June 1990, with most from Queensland and four from the Northern Territory.Marine Bites and Stings Dr Mark Little There were 14 calls to the Queensland Poisons Information System in 2008 regarding stonefish poison.annual report 2008, Queensland Poisons Information Centre

Fatal incidents NameAgeDateLocationJoseph Leathom Wassell417 April 1915Thursday Island, AustraliaMarine Bites and Stings Dr Mark Little name not given586 August 2010Nago, Okinawa, Japan

As food Synanceia are edible to humans if properly prepared. The protein-based venom breaks down quickly when heated, and raw stonefish served as part of sashimi is rendered harmless simply by removing the dorsal fins, which are the main source of venom. The fish are considered a delicacy in many parts of Asia, including south Japan, south Fujian, Guangdong in China, Hong Kong and some parts of Vietnam. In the Hokkien-speaking area, they are considered delicacies and good for health. The meat of Synanceia is white, dense and sweet and the skin is edible. They are usually cooked with ginger into a clear soup and sometimes served raw as sashimi.

References

Synanceia

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