Crab, Brown

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Crab, Brown

Image | Sarah McCartney, Copyright Cornwall Wildlife Trust

Description

Brown crabs, also known as edible crabs, or in Cornwall 'Pasty Crabs', are the nations favourite crustacean. The pasty shaped shell houses soft and flavoursome brown meat and the legs and claws are packed with the more delicate flavoured white meat. Crabs are at their best in the winter months but can be enjoyed all year round thanks to the sustainable nature of this fishery. There are loads of different ways to enjoy crab meat.. find recipes and more infomation here!


Sustainability Overview

Brown crab stocks are healthy in Cornish waters and the majority of brown crab landed to our ports are caught with crab pots, a selective and low impact fishing method. Always look for fresh local pot caught crab.  Best choice for brown crabs are those caught using pots in inshore waters (within Cornwall’s 6 mile limit) where minimum landing sizes are higher.

Brown crabs have a relatively low vulnerability to fishing as a female crab can produce up to 3 million eggs each winter, they grow relatively fast and use our shallow rocky intertidal areas (of which Cornwall has a huge area) as protected nursery grounds.

The main fishing method used for brown crab is potting – this is a selective fishing method, with very little impact on the seabed. Undersized and berried crabs can be returned safely to the sea unharmed, so there is no problem with killing undersized crabs (discards). 
As a result pot caught Brown crab is one of the most sustainable choices of seafood you can make, even in winter months.
 
Find local fish

When is best to eat?

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Gill Netting

outside 6 mile limit

Crabs caught thorough entanglement in gill nets are lower quality and outside the 6 mile limit there are smaller minimum landing sizes. Some issues with accidental by-catch with this method.

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Potting

Cornish waters inside 6 mile limit

Potting is a selective and low impact method and within the 6 mile limits Cornwall Inshore Fisheries and Conservation authority monitor and strictly regulate the fishery.

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Gill Netting

Inside Cornwall's 6 mile limit

Crabs caught thorough entanglement in gill nets are lower quality. There are some issues with accidental by-catch with this method.

Learn more
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Potting

Cornish Waters outside 6 mile limit

Potting is a selective and low impact method but outside the 6 mile limits there are smaller minimum landing sizes for brown crab.

Learn more
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Beam Trawling

Cornish waters outside 6 mile limit

Outside 6 mile limit. Beam trawls have considerable impact on the seabed and crabs caught in trawls are often more damaged than those caught in pots. There are also issues with unwanted by catch.

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How we rate fish

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Cornwall Good Seafood Guide rates fish on sustainability using a scale of 1 to 5.

1, 2 and 3 are recommended, Fish to avoid are rated 5.

We use the system devised by the Marine Conservation Society (MCS) so our scores are comparable with the scores produced by MCS for the UK and fisheries from all around the world. For more information on scoring click here.

Sustainability Overview

Brown crab stocks are healthy in Cornish waters and the majority of brown crab landed to our ports are caught with crab pots, a selective and low impact fishing method. Always look for fresh local pot caught crab.  Best choice for brown crabs are those caught using pots in inshore waters (within Cornwall’s 6 mile limit) where minimum landing sizes are higher.

Brown crabs have a relatively low vulnerability to fishing as a female crab can produce up to 3 million eggs each winter, they grow relatively fast and use our shallow rocky intertidal areas (of which Cornwall has a huge area) as protected nursery grounds.

The main fishing method used for brown crab is potting – this is a selective fishing method, with very little impact on the seabed. Undersized and berried crabs can be returned safely to the sea unharmed, so there is no problem with killing undersized crabs (discards). 
As a result pot caught Brown crab is one of the most sustainable choices of seafood you can make, even in winter months.
 
Crab, Brown

Biology

With their characteristic Cornish pasty-shaped shell, brown crabs are easily recognisable. They can live for up to 100 years and grow to a maximum size of 27.5 cm shell width and weigh up to 4 kilos! Although the average size adult crab is between 10 and 15 years old. An adult female brown crab lays between 250,000 and 3 million eggs during the winter months. In Cornwall it is illegal to land crabs carring eggs (known as berried crabs) so they are returend to the sea where they will be allowed to spawn. Rocky shores around Cornwall are teeming with juvenile edible crabs which can be found beneath rocks and seaweeds on low tides. As they get older they move to deeper water and the largest edible crabs are caught in deep water off the Lizard in Southern Cornwall. Like all crustaceans Brown crabs have to moult, shedding their shells as they grow. Juveniles moult several times per year but as they get larger the rate of moulting slows to once or less per year. After moulting the crab inflates every section of the shell with seawater and a chemical reaction takes place hardening the shell up. The new shell takes a few weeks to harden fully and it takes longer for the crabs muscles to grow to fill the shell. During this time the shell is pale and the crabs are not landed by fishermen as they are full of water.  In the winter months they are less likely to moult so the quality of brown crabs is best at this time of year although crabs are landed all through the year. Brown crabs use their massive powerful claws to crack the shells of mussels and other shellfish and even other crabs. They also scavenge for food and are attracted to fishermen’s pots by the scent of bait. Crabs are caught in largest numbers on and near hard rocky ground.  
 

Stock Info

From MMO landings data and discussion with fishermen it is clear that although there are now more fishermen than ever fishing for crabs around Cornwalls coast this low impact and selective method, combined with appropriate minimum sizes has continally yeilded good returns of crabs and is proving itself to be a steady and sustainable fishery.
 
According to government scientists the status of the stock of brown crab in Cornish waters is good. In the Western English Channel (off cornwalls south coast it is around the level required to produce maximum sustainable yeild (CEFAS 2014). In the Celtic sea (off Cornwalls North Coast) the stocks of Edible crab are approaching the level associated with Maximum Sustainable Yield (CEFAS (2014). In both Celtic Seas and Western channel the fishing levels are sustainable - slightly above maximum sustainable yeild in Celtic sea and around maximum sustianable yeild in the Western Channel. This infomation was also backed up by summaries made by Project inshore in 2013 who state that although fishing levels are higher than optimal levels, landings are increasing despite falling fishing effort in the Celtic sea and that the situation is even better in the Western Channel area.
 
 
A report by Cornwall Inshore Fisheries and Conservation Authority in 2006 showed that at that time CPUE (catch per unit effort) is increasing slightly and that landings are remaining constant in Cornish inshore pot fishery. This is a good sign for the sustainabiltiy of this stock.
 
 
 

Management

The number of vessels fishing is restricted by a Potting licence system. Actual numbers of pots being used are not restricted. 
Cornwall Inshore Fisheries and Conservation Authority has a permit system for crab potting and a larger minimum size than elsewhere in EU waters. Only a maximum of 75kg of brown crab can be caught as by-catch by netters per day.
There is no restriction on the quantity of brown crab being caught as they are not a quota species.  There is an ICES working group on Crab and CEFAS carry out stock assessment work on this species but management could be improved according to the Shellfish Association of Great Britain who strongly argue that pot numbers should be capped. (Bannister 2009) (Nautilus consultants 2009).
 
Cefas stock assessment and ICES working group on Crab show that this stock is being monitored for future management.
The CIFCA shellfish licence requires all fishermen to report their catches in detail each month so that the fishery can be monitored. 
No more than 30kg of detached brown crab or spider crab claws can be retained on board any vessel or landed at any one time. This prevents the practice of breaking of the claws when unpicking crabs from nets and then throwing back the crabs with no claws. 
Minimum landing sizes within Cornwall IFCA district (within the 6 mile limit) are larger than outside, females 150cm and males. It is also illegal to land berried female brown crabs within the CIFCA district. Boats operating outide Cornwalls  6 mile limit that are over 15m in length are restricted by DEFRA effort regulations (KW/hours). Also known as days at sea regulations.

Capture Info

The majority of crabs landed to Cornwall are caught in baited crab or lobster pots. This is a low impact, selective fishing method. Any undersized or recently moulted crabs can be returned, unharmed, to the sea to be caught another day. The gear has little physical impact on the seabed (in Cornwall our rocky reefs are hard so aren’t eroded by pots landing on them- unlike chalk reefs in the English Channel). Brown crab are also caught in significant numbers as by-catch in net and trawl fisheries. Crabs tangled up in gill nets are difficult to un-pick and sometimes as a result the claws are removed to disentangle them, and qality of the catch can be reduced. Netters have a limit of 30kg of unattached crab claws per day in Cornish waters. Nets have issues with accidental by catch of other species such as skates, sharks, seabirds and cetaceans. Trawls have a greater impact on the seabed than pots and undersized crabs that are caught in nets or trawls are often much more damaged than those returned from crab pots and less likely to survive. Boats operating outside Cornwalls 6 mile limit that are over 15m in length are restricted by effort restrictions (KW/hours) which restrict fishing effort. Many will adhere to the minimum size limits set within Cornwalls fsihing district but by law eu minimum landing sizes apply which are smaller than those within Cornwalls 6 mile limit.

References

Report 2012 ICES Crab Working Group. www.ices.dk 
Nautilus consultants 2009 Brown crab management report 
Eno N.C. et al, 2001, Effects of Crustacean traps on Benthic fauna, ICES journal of Marine Science
Bannister. R. C. A 2009 On the Management of Brown Crab Fisheries, Shellfish Association of Great Britain
Project inshore pre assessment database   http://msc.solidproject.co.uk/msc-project-inshore.aspx?a=CW&s=
 

Recipes for Crab, Brown, Edible

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