Cockle, cockles

Cerastoderma edule

Method of production — Caught at sea
Capture method — Hydraulic dredge
Capture area — North East Atlantic (FAO 27)
Stock area — UK
Stock detail — All Areas
Picture of Cockle, cockles

Sustainability rating three info

Sustainability overview

Hydraulic dredging removes undersized animals from the fishery, along with other invertebrates such as worms, which form a vital part of the ecosystem, being prey species for many fish and crustacea. This method of fishing is prohibited by local byelaws in some coastal areas in England, e.g. in Cornwall. Choose cockles harvested by more sustainable methods such as licensed hand gathering. Avoid eating them during breeding season from March to July. Burry Inlet cockles and cockles from the Dee Estuary are both MSC certified and provide the most sustainable options in the UK.

Biology

The common cockle is a bivalve mollusc found buried in mud and sand in estuaries and on beaches. Cockles have distinctive rounded shells that are slightly heart shaped. It is a bivalve (two identical shells) belonging to the family Cardidae meaning 'heart-shaped' . An organ called a siphon allows the animal to feed and breathe whilst buried in the sand. They can jump by bending and straightening the foot - the end bit- which is often coloured red and called the 'red nose'. The shell size is up to 5cm long, although average sizes tend to be around 3-4cm. Maturity occurs at a shell length of around 2cm. Cockles spawn from March to August, although exact times will vary from region to region.

Stock information

Stock Area

UK

Stock information

Species widely distributed on coastlines throughout North Atlantic region. Cockle stocks are potentially vulnerable to local over-exploitation and depletion. Cockles breed from around Easter to end of summer.

Management

Cockle beds are managed in inshore waters in England through local byelaws enforced by Inshore Fishery Conservation Authorities (IFCAs). Byelaws may prohibit landing of cockles below a minimum landing size (MLS) and/or impose restrictions on the amount collected and/or the method by which they are collected. For example, in the Southern IFCA District fishing for cockles is only permitted by hand, dredge or pump scoop dredge. There are also prohibitions on using or carrying a Shellfish Dredge, Scoop or Handrake in Certain Areas of Poole Harbour or in Bird Sensitive Areas of Newton Bay, Ower Bay, Wych Lake and Middlebere Lake, Arne Bay and Keysworth.

Capture Information

Hydraulic dredges use jets of water (or air) to liquidise the sediment, which is then lifted through a pipe to be sorted onboard the fishing vessel. This type of dredge removes undersized animals from the fishery along with other invertabrates, such as worms, which form a vital part of the ecosystem, being a prey species for many fish and crustacea. Mechanical harvesting, e.g. by tractor, can remove cockles in large quantities thus reducing their numbers and overall size. The method also disturbs seabed, beach or estuary depending on distribution, and can remove very large quantities of cockles which are a prey species for birds and other marine life. This method of fishing is prohibited by local bylaws in some coastal areas in England, e.g. Cornwall.