Brown crab

This stock is data limited. There is concern for the biomass due to a decline in the abundance index, and concern for fishing pressure as F is above FMSY in all areas where data is available (for either males, females, or both).Brown crab is the most important crab species caught in Scotland, in terms of weight and value and it is found all around the Scottish coast. For assessment purposes, the Scottish creel fishing grounds are divided into 12 assessment areas. The principal fishing areas for brown crab in Scotland are the Hebrides, Orkney, Sule, East Coast, Papa and South Minch.The most recent stock assessment (2019) indicated that in the Hebrides, North Coast, South Minch and Sule areas, fishing mortality (F) was above FMSY. In the Clyde and Ullapool, fishing mortality for females was at FMSY while males were fished above FMSY. Therefore, there is concern for fishing pressure. Brown crab has a low vulnerability to fishing pressure.The abundance index estimated in the west coast dredge survey increased gradually from 2008 to 2016 and declined from 2016 to 2020. Therefore, there is concern for the biomass.The estimated recruitment index for the West coast displays a steady trend between 2008 and 2013. Recruitment then rose to a peak in 2015 at near 30 crabs per km2 before declining to just below 10 crabs per km2 in 2019.

Management requires considerable improvement and effort controls are needed to improve the stock.There are some management measures in place for this stock, 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.In Scotland (excluding Shetland), the minimum conservation reference size is 150 mm carapace length. Since May 2025, it is now illegal to land a berried (egg-bearing) brown crab in Scotland, in line with the rest of the UK.In Scotland, vessels fishing commercially for brown, velvet, spider, or green crab, lobster or crawfish must have a license with shellfish entitlement. Owners of vessels that are 10m and under with a shellfish entitlement are required to complete the FISH1 form for all landings of crabs and lobsters and submit it on a weekly basis to the Fishery Office at which the vessel is administered. For vessels that are over 10m in length, data on fishing activity by trip must be recorded in an EU logbook and submitted to the Fishery Office within 48 hours of landing. Licensed fishing vessels that do not hold a shellfish entitlement can land a maximum of 5 lobsters and 25 crabs per day. Regulations effective from April 2017, restrict the numbers of certain shellfish species that can be taken by unlicensed fishing boats. The restrictions are set daily per vessel as 1 lobster and 5 crabs (of any species). There is currently a restrictive licensing system, whereby no new licenses and entitlements are being granted.The Western Waters effort regime limits the number of days at sea that UK vessels over 15 metres fishing for crabs and scallop in ICES Area 7 can have, to keep the fishery within EU effort limits. The number of allowed days are detailed in each vessel's fishing license, and are not transferrable between vessels or years. Uptake is monitored monthly by the Marine Management Organisation and enforced by local fisheries management authorities. In 2021, there was a 44% uptake of the allowance for the crab sector (fishing for Edible/Brown Crab (Cancer Pagurus) and spider crab (Maja Squinado)). However, this is a lower percentage than usual (for example, in 2019, it was 92%), possibly due to supply chain issues caused by the coronavirus pandemic.In the West coast region, a voluntary pot limit is being trialled for a 3 year period, run by fishermen, with the aim to reverse declining catch per unit effort rates. In the Outer Hebrides, the pot limit ranges from 800 - 1,800 pots, depending on the vessel size. In the Firth of Clyde, the limit is 650 pots. The outcome of this trial is not yet known.The UK Fisheries Act came into force in January 2021 and requires the development of Fisheries Management Plans (FMPs). There are no details yet on how and when these will be developed. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. MCS is keen to see FMPs for all commercially exploited stocks, especially where stocks are depleted, that include:Targets for fishing pressure and biomass, and additional management when those targets are not being metTimeframes for stock recoveryTechnologies such as Remote Electronic Monitoring (REM) to support data collection and improve transparency and accountabilityConsideration of wider environmental impacts of the fishery

Entanglement rates in creel fisheries on the west coast are possibly contributing to the decline or preventing the recovery of minke whales.Brown crab and European lobster are fished together in a mixed fishery with seasonal and regional variation in target species taking place. The key fishing season for European lobster in the UK takes place from May to December. Lobsters are caught in pots, also known as creels, and can be fished individually or as part of a fleet of up to 100 pots, depending on the size of the boat and crew. Pots are portable traps made of wood or steel wire and plastic. The lobster 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. North Sea cod may be caught as bycatch in this fishery, and they will generally be undersized. There is a legal obligation to release undersized cod.In creel fisheries, there is potential for entanglement of endangered, threatened or protected (ETP) species from the ropes attached to the pots. A report in 2010 estimated that around 7.5km of creel lines would be in Scottish waters throughout most of the year. These creels are targeting crab, lobster and Norway lobster. Whales entanglements usually occur in the groundlines between creels. Whales become entangled in groundline because the rope used is buoyant and floats in loops between pots, rather than lying on the seabed.The main species at risk are minke and humpback whales and basking sharks. A 2022 study has estimated that on the west coast of Scotland, 189 minke whales and 29 humpback whales have been entangled from 2009-2019 (Out of a total of 302 minke whales and 64 humpback in Scotland overall). In the west coast, there is a high level of overlap between minke whales and creels, with observed densities for minke whales being much higher than those for humpback whales. Observed densities for minke whales are much higher than those for humpbacks and estimated numbers of entanglements are also higher. Minke whales entanglements are likely to be acutely fatal, with 84% of entangled minke whales found by fishers being already dead. In the area covering the west coast of Scotland, inside of the Outer Hebrides, it is estimated that there are 16 fatal entanglements per year. Potential biological removal (PBR) is used to assess the conservation implications of bycatch. In this area, the PBR for minke whales would be 4.6 individuals per year, this is less than a third of the estimated annual number of fatal entangelements. This suggests a risk of localised depletion for minke whales.Marine mammal bycatch reporting requirements were only introduced in the UK in November 2021, so monitoring to date has been poor. From 2021, new conditions introduced for fishing licenses require all bycatch of marine mammals to be reported within 48 hours of the end of the fishing trip. However, whale entanglements will still be underreported if whales break free or animals are caught in abandoned, lost or otherwise discarded fishing gear.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.

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