5/17/2023 0 Comments Scallop dredgeThe number of dredges towed by UK vessels depends on local regulations and vessel size. There are usually between 2 and 22 dredges attached per side to a towing bar with rubber wheels on each end designed to roll along the seabed. The teeth can flex backwards, allowing them to pass over harder ground without snagging and breaking, and improving catch efficiency. This is normally a “Newhaven” type dredge, fitted with a spring-loaded tooth bar. The main method of capture of the king scallop in the UK is by dredge. Scallops are the third most valuable species landed by UK vessels, worth £74.1 million in first sale value in 2016, £74.5 million in 2017, £71.3 million in 2018, and £58.6 million in 2019. King scallops are an important national marine resource to the United Kingdom. A report on this research is expected to be available in late 2022. All sampling is being conducted in collaboration with the commercial scallop divers across D&S IFCA’s District. The project uses weekly samples of twenty scallops per area, all of which are being measured and assessed in the laboratory. Therefore, D&S IFCA is undertaking a project with the University of Plymouth to study spawning timing and how it varies across a range of areas: Lyme Bay, Torbay, and Start Bay. Spawning usually takes place during the spring and summer however, the timing can vary between areas, and more evidence is required on spawning times in South Devon. During spawning either the sperm or eggs are released first into the water column where the fertilisation takes place. The king scallop is a simultaneous hermaphrodite with the gonad containing a creamy-coloured testis and an orange-coloured ovary. The distribution within scallop beds has been described as patchy, with densities rarely found at one scallop per m² and are more typically 0.1-0.01 scallops per m² on good fishing grounds. Settlement is on sediment, usually made up of fine sand or gravel and sometimes mud. The distribution range for king scallops is from Norway to the Atlantic coast of Spain, at depths of up to 200m. It has several predators including large crabs, cephalopods, and a range of starfish. The scallop has a number of eyes around the shell margin, each of which can process images. The scallop recesses into the sediment and orientates to the water current which is thought to help them feed more efficiently and imposes rhythms of feeding and digestion, phased with the tidal cycle. The king scallop is a filter feeder, pumping water through a filter in the gill chamber to remove particulate organic matter and phytoplankton. They reach reproductive maturity at a minimum size of 60mm and are fully mature at 3-5 years, living up to 20 years. Maximum shell size varies with most being <150mm at the widest part of the shell. Sessile invertebrates, such as barnacles and tube worms often grow on the shells. Both are marked with up to 17 distinct radiating ribs. The lower (right) valve of the king scallop is convex and off-white in colour and the upper (left) valve is flat and reddish-brown. D&S IFCA Byelaw Book and Minimum Conservation Reference Size List.South Devon IPA - Trawling & Crabbing Chart.Current Permit Byelaws & Permit Conditions.Devon and Severn IFCA Enforcement & Compliance Strategy.
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