Weever Fish

Weever fish are a poisonous species of fish from the Trachinidae family. While there are nine species of weever fish in total the only two found in UK waters are the lesser and greater weever. Weever fish are a rare example of a poisonous fish which inhabits British waters – both the lesser and the greater weever have spines on their backs and gill covers which secrete a potent venom. Lesser weever fish come into shallow water and are the species most likely to be encountered by both anglers and bathers in the summer months.

Lesser Weever

Lesser Weever Fish
  • Scientific name: Echiichthys vipera
  • Also known as: Sting Fish
  • Size: Up to 8ins/20cm, but commonly 8-12cm
  • UK minimum size: N/a
  • UK shore caught record: 3oz 4dr
  • IUCN Status: NE (Not Evaluated)
  • Distribution: Found all around the UK and Ireland over sandy and muddy seabeds.
  • Feeds on: Small and immature fish, fish fry, crustaceans and prawns.
  • Description: Small fish with thickset body. Colour is silver to white with brown to yellow mottled pattern. Upturned mouth is relatively large, and eyes are located at top of head. First dorsal fin is black in colour and made up of five spines which contain venom, as do additional spines located on the gill covers. Second dorsal fin runs the length of the rest of the body, as does the anal fin. Tail is small and usually has a black tip.

Despite the fact that the lesser weever is a small fish (the UK shore caught record is under four ounces) it is one of the most dangerous fish found in UK waters due to the potent venom it can deliver. Lesser weever fish are a constant hazard for anglers, bathers and tourists and commercial fishermen in the warm summer months when this species comes closest to the shore.

Weever Fish Size

The small size of a lesser weever fish can be seen in this picture. The tape measure is in centimeters.

Lesser weever fish are common all around the UK and Ireland over sandy, muddy and light shingle seabeds, and is also present in European waters such as the Mediterranean. In winter the lesser weever fish moves into deeper water, usually over one hundred metres deep or more. However, in summer time lesser weever fish come inshore and can be found in very shallow water. In these months lesser weever fish bury themselves under the sand with just their eyes and spines protruding. They are aggressive predators and will snap at any small fish, crustaceans or prawns which pass them. Once the sun has started to set lesser weever fish will emerge from the sand, sometimes forming in small loose shoals and swim freely, hunting for small fish. Weever fish are poor swimmers but have a surprising burst of speed over a few metres and use this to catch their prey.

It is during these summer months that weever fish come into contact with humans. Commercial fishermen are stung by weever fish that are caught in nets which are being hauled on board, and bathers sometimes step on weevers which have buried themselves in sand near to the shore. Anglers are most likely to come across the lesser weever when fishing for mackerel with daylights or feathers as weevers often go for these lures when they are hunting, although they will also take small baits such as ragworm, prawn and mackerel strip. Anglers who are unaware of the lesser weever and mistake it for a sprat may swing the fish into their hands to unhook it and receive a deeply unpleasant surprise if the spines of the weever fish spike their skin.

Effects of Weever Fish Venom

Once the spines of the weever fish have pierced skin the venom is discharged. At first the only pain will be from the wound to the flesh, but soon the poison kicks in causing pain which can be excruciating. For around two hours the part of the body which has been stung will become red, inflamed and swell up. There may also be extreme numbness and in extreme cases there can even be localised paralysis for a short period of time. Usually the pain begins to subside after a few hours, and should be gone within 12 to 24 hours. Further complications will emerge if the spines have broken off into the wound, as they may need to be removed before the pain will subside.

Weever fish caught by angler

Weever fish caught by angler.

If a healthy adult is stung by a lesser weever fish it is not usually necessary to see medical attention. The best course of action is to place the injured body part into very hot water (as hot as the victim can stand without scalding) as the poison is protein based it is destroyed by heat. If children, elderly people or those with underlying health issues are stung by a weever fish it is wise to seek immediate medical attention. On a busy beach life guards will be trained to deal with weever fish stings, or refer the victim on to more advanced medical care if this is necessary. The NHS website has further information on what to do in the event of a weever fish sting – read it here.

Greater Weever

Greater Weever

The other species of weever fish found around the UK is the greater weever (Trachinus draco). This fish is bigger than the lesser weever, reaching up to two feet in length and can weight up to four pounds, although typically it is half this size. It has the same venomous dorsal fin spines as its smaller relative. It is not as common as the lesser weever and prefers much deeper water of around one hundred metres, meaning it is rarely encountered by anglers or bathers. However, there is a British shore caught record for this species: a specimen of 1lb 9oz caught by P. Robinson off the coast of Cornwall in 2014.

Commercial Value and Origin of Name

Despite its venomous nature the greater weever fish is edible and is of minor commercial importance, with a limited market for the greater weever as a food fish existing in Scandinavia and Southern European countries. The weever fish is often mistakenly referred to as the ‘weaver fish’. The spelling weever comes from the Old French word ‘wivre’ which means dragon and was itself derived from the Latin word for viper.

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