Greater weever
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| Greater weever | ||||||||||||||
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| Trachinus draco Linnaeus, 1758 |
The greater weever, Trachinus draco, is a weever fish of the family Trachinidae. It is less common than the lesser weever.
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[edit] Description
The color of its body is a greenish yellow or lime, to dark green and brown, on the head and back, with pale sides, and with yellowish to bluish-brown oblique lines.
The greater weever's body is elongate, tapered, laterally compressed, with a large head, and length up to six times its height. The upper rim of the eye has two to three small open spines, in front of each eye.
Its pectoral fin is rounded with a notch. On the first dorsal fin, both of the spines, and that of the gill covers, have venom glands attached to them. The spines are grooved, and when pressed, toxin is driven up the grooves. Care is needed due to the poison causing localized discomfort and swelling, which can occasionally cause death. The wound should be allowed to bleed freely, to help expel toxin, and then may be treated with potassium permanganate solution, or very hot water. Medical help should be sought.
The mouth is huge and is set obliquely. The eyes are placed toward the top of the head. The dorsal fin is blackish. The second dorsal fin, and anal fins, have a yellow stripe running their length.
[edit] Habitat
It is found in the Eastern Atlantic, Norway to Morocco, Madeira and the Canary Islands, including the Mediterranean and the Black Sea. It is found in all waters of the United Kingdom. Climate is temperate and geographically it is found within 66° N - 27° N, 19° W - 42° E.
The greater weever, like the lesser weever, is found on muddy, sandy or gravelly bottoms, from a few m to about 150 m. It usually rests on the bottom, with eyes closed often, and the tip of the first dorsal fin exposed. At night, they swim around wanderously, even pelagically, feeding on crustaceans,shrimps and crabs, as well as smaller fish.
Along the scales are dark markings. The anterior dorsal fin and contains various venomous spines.
[edit] Importance to humans
The greater weever has minor commercial importance, and is a gamefish. It can be found in aquariums, mainly those that are public. This weever has medium resilience. The minimum population (that is doubling) time 1.4 to 4.4 years (assuming tm=2-4).
To be utilized it can be fresh or frozen, can be fried, broiled, boiled and baked.
[edit] Reproduction
Spawning begins place in June and August, pelagic eggs are 1 mm. The greater weever breeds from June to August.
[edit] As sport
A male unsexed fish's average size is 53 cm TL. It weighs about 1.86 kg. The UK Record Weights from rod/line Shore stands as 1lb-07oz-15dr, and on boat 2lb-00oz-13dr.
[edit] The Greater Weever bite
The interaction of these two muscles (flexors and Expander) attached to the plate opercularis increases the exposed portion of the spine in order to facilitate the injection of venom. These two muscles are antagonistic, the contraction of one stands spine, and thus increases the exposed it that the membrane surrounding the spine is not elastic, while the contraction of the other reduces the size the exposed. The length of the exposed part of the spine depends on the angle of the opening of the cover.
The outer membrane of the spine presses on with venom gland during the contraction of the muscle flexeur, this pressure can bring out the venom gland outwards through the spine.
The toxin in the venom is thermo-sensible which is deteriorating from 40 ° C, in the event of being bitten by the greater weever, put hot water at the site of the sting and move as quickly to the hospital for treatment.
[edit] References
- Greater Weever. Retrieved on 2006-09-22.
- Auerbach, Campbell, P.S., Dr.. Greater Weever Species Summary. Retrieved on 2006-09-22.
