Brown crab

There is concern for the stock level and concern for the fishing level of brown crab in the Central North Sea.Stock assessments for brown crab in England have been carried out approximately every 2-3 years by CEFAS since 2012. The most recent assessment was published in 2024, using data up to 2023. Brown crab is widely distributed in coastal waters of the Mediterranean, Atlantic, English Channel and North Sea. CEFAS defines five Crab Fishery Units (CFU’s) for England: Central North Sea, Southern North Sea, Eastern English Channel, Western English Channel and Celtic Sea.The brown crab stock assessment uses 35% of virgin Spawner per Recruit (SpR, the ratio of spawning biomass produced by a length class if 35% of the population is fished compared to an unfished population) as the Maximum Sustainable Yield (MSY) level proxy. This is commonly used around the world to estimate the fishing rate likely to deliver MSY. A limit reference point has also been calculated and having fisheries operating beyond this level is considered to carry higher risk to the production of further generations. This value is defined as 15% of virgin SpR.In 2023, biomass is between the limit and MSY target reference points for females, and at the limit reference point for males. Both sexes have been in decline since 2019.Fishing mortality is between the target and limit reference point for males and females. Females have shown an increase in fishing mortality over the last decade.Cefas reports that a recent expansion in fishing activity in both pot numbers and distribution may be partially responsible for a large increase in landings seen in 2018 -2019 which the biomass model interpreted as an increase in spawning stock. Therefore, the spawning stock data must be treated with caution.Some technology creep is likely to have occurred as either vessels or hauling equipment have been upgraded, improving efficiency. There has also been some transition to higher capacity vessels able to handle a larger number of pots. The inshore fishery has seen an increase in pots hauled and pots set across the North Eastern IFCA range.In autumn 2021, a mass crustacean mortality event occurred inshore near the River Tees south to Scarborough, the cause of which remains uncertain. It is unknown if this has had an impact on the fishery.

This assessment is for the brown crab fishery beyond 6nm in the Central North Sea. Some national management measures are in place, however, they are not effective in managing the stock.In the offshore fishery, there are some management measures in place, but there are no catch limits in place to prevent overexploitation. There is no limit on creel numbers, no spatial controls and no Total Allowable Catch (TAC) for either the fishery as a whole, or individual vessels. There are also no tools available to implement a harvest control rule to provide a quick management response to adverse trends in stock indicators.All vessels registered in the UK must have a domestic fishing vessel license to fish within the UK EEZ for sea fish that will be sold. No new licenses are being issued. All commercial vessels under 10m, with a shellfish license, are required to complete Monthly Shellfish Activity Return (MSAR) forms for the Marine Management Organisation (MMO). These must include the catch and retained weight each day along with the date, name of vessel, vessel registration number, gear type, area and port of landing. All vessels over 10m do not need to complete MSAR forms as they will be completing a logbook of catches. For all vessels, effort is reported as days fished, and not as pots fished.National legislation in England and Wales also prohibits the landing of berried and soft crabs. In addition, when using pots or creels, a maximum of 1% by weight of the total catch of brown crabs landed may consist of detached claws. For all other gear types, a maximum of 75kg of detached claws may be landed. In many areas, market preference can also have influence on the crabs which are landed, as those having an 'unclean' appearance, due to disease or discolouration, or those missing both claws, can be seen as unmarketable.In England, the minimum conservation reference size (MCRS) varies between 115mm and 160mm carapace width, depending on the area.The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras is one of the most cost-effective tools for providing reliable fisheries data and aiding informed management decisions. Fully monitored fisheries enhance collaboration, data accuracy, stock recovery, and reduce impacts on marine wildlife and habitats. However, the full potential of REM may only be achieved when it tracks fishing location and documents catch and bycatch, particularly where vulnerable species and habitats are at risk. As of January 2024, the EU is introducing a Remote Electronic Monitoring (REM) mandate for EU vessels, including CCTV cameras on vessels 18m or more that pose a potential risk of non-compliance, within the next 4 years. Across the UK, different approaches to REM are being taken and legislation is expected to be in place across all 4 countries within the next few years.The Fisheries Act (2020) requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) in the UK. 43 FMPs have been proposed and are at various stages of development and implementation, these should all be published by the end of 2028. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. It is also essential the UK governments define and adopt a standardised approach or model across the four nations to a universally defined FMP design, to ensure the consistence, quality and coherence of all the proposal FMPs.The Marine Conservation Society is keen to see publicly available Fishery Management Plans for all commercially exploited stocks, especially where stocks are depleted, that include:An overview of the fishery including current stock status, spatial coverage, current fishing methods and impactsTargets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best scientific evidenceTimeframes for stock recoveryImproved data collection, transparency, and accountability, supported by technologies such as Remote Electronic Monitoring (REM)Consideration of wider environmental impacts of the fishery, including habitat impacts and minimising bycatchStakeholder engagementA crab and lobster FMP for English waters has been proposed, coordinated by Defra, in partnership with Seafish that incorporates this stock. At the time of writing, it is too soon to know whether proposed management measures will be effective in managing the stock. For more information about this FMP and expected progress and timelines, see https://www.gov.uk/government/publications/crab-and-lobster-fisheries-management-plan-fmp-for-english-waters.

Pot fishing is generally considered very low impact as it is selective for larger individuals and has minimal impact on the surrounding environment.In the UK, brown crab and European lobster are fished together in a mixed fishery with seasonal and regional variation of target species taking place. The key fishing season for brown crab in the UK takes place from May to December. Crabs are caught in pots, also known as creels, and can be fished individually or as part of a fleet of up of hundreds of pots, depending on the size of the boat and crew. Pots are portable traps made of wood or steel wire and plastic. The crab is baited into the initial part (the chamber) and moves into the secondary part (the parlour) where it becomes trapped.In brown crab fisheries, there is no legislation or regulation to standardise the type of pot used. They tend to be highly selective as undersized animals can be returned to the sea alive and survival rates for non-target organisms are thought to be high. More than half of the bycatch caught are predicted to survive, although there is little available research to prove this. Measures to further reduce bycatch include the use of escape panels to allow undersize animals and bycatch to escape pots.Habitat impacts from potting are low but can occur during deployment, soak time or hauling of the pot, impacting the benthic habitat and associated species through contact with the pot or end weight, or by scouring from ropes. Research that has taken place suggests that while some damage does occur, it is unlikely to be significant unless potting intensity is high (defined as approximately 30 pots per 500 square metres). Most damage occurs where traps are set in rocky habitats that are home to corals, sponges, sea whips and other large emergent species. These habitats and species provide nursery areas, refuges from predators and habitat for the settlement of invertebrate spat.In some circumstances, there can be instances of ghost fishing, when lost fishing gear continues to fish and can entangle a variety of species, but this can be minimised by using appropriate gear and release devices.The type of bait used in crab and lobster fishing is dependent on the area and availability of suitable products. Common bait species include mackerel and herring. However, there is concern that a significant amount of unreported bycatch from net fisheries are also being used as bait. This can include wrasse, conger eel, and low value species such as dogfish. Bycatch taken in creels, such as cephalopods, are also known to be used as bait. The environmental impact of this is unknown.

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