Crab sheltering devices in south-western England

Collection of peeler and soft shell crabs has been undertaken for many years by recreational anglers and collectors supplying the retail bait trade. Crabs undergoing these vulnerable moulting stages are thought to release pheromones making them particularly highly valued as bait for certain fish species, including bass. Collection has traditionally been undertaken by searching underneath boulders on rocky shores, where moulting crabs usually hide from predators. The damaging effects of boulder turning on rocky shore communities has been described by Bell et al. 1984, Cryer et al. 1987, Liddiard et al. 1989, and others.

A relatively recent development has been the extension of crab collection to sediment shores, particularly in sheltered inlets where tiles, pipes and guttering may be laid on the shore to act as crab shelters. This activity started in the south-west of England, where the warm climate results in a long moulting and harvesting season, and has recently expanded greatly, causing management problems in several estuaries. These crabs are a very valuable product, being worth some 40-50p each in summer and 80p to 1 in winter when supplies are very low and demand at its highest. Because the activity has only intensified within the last few years, there are very few studies available on its extent and impact. There does not yet appear to be any overall pattern to the management of the activity, because patterns of land ownership and management vary considerably from site to site.

An undergraduate project (Godden 1995) investigated the trapping of shore crabs Carcinus maenus using guttering and tiles in the south Devon estuaries, primarily around Plymouth. He found that numbers had grown in recent years from none to 8,750 traps at Plymouth, and had increased 10-fold in the Exe and Teign estuaries. It was hard to identify any depletion in crab numbers, due to recolonisation by larval stages of crab. Shellfish farmers have not reportedly noticed any reduction in crab numbers on their oyster and mussel beds in estuaries where crab collection is taking place on a large scale (P. Gibbon pers. comm.). Godden also noted that the shelters also provided habitat for other marine plants and algae, and sources of food for fish and birds.

The Tamar Estuaries Bait Collection Working Group was set up when bait collection (particularly the level and impact of crab trapping and worm digging and the abuse of access and property rights) was identified as an issue of concern by the Tamar Estuaries Management Plan Consultative Document. The Group is comprised of recreational and commercial collectors and recreational marine fishery bodies. Only a few years after Godden’s report, the Tamar Estuaries Bait Collection Working Group (1998) reported that there were some 20,000 crab traps in the Tamar Estuaries, of which some 8,000 are commercially used. Commercial traps yield some 90,000 crabs, some 30% of which supply local angling shops and 70% is sold to other parts of the UK. Recreational anglers (who are less active and effective collectors) take some 20,000 annually. The result has been widespread concern over the visual impacts of these tiles, their potential impact on wildlife (crab populations, sediment communities and birds), navigation and moorings, and beach recreation, and future pollution caused by the breakdown of car tyres, where used. Finally, issues of trespass and installation of shelters on private land have caused problems, with landowners removing large numbers of shelters from private foreshore and nature reserves and having to dispose of these.

The Group recommends a voluntary management approach involving all key players, in harmony with the Tamar Estuaries Management Plan. Specifically, the development and implementation of a Bait Collectors’ Code specifically for the estuary and an angler/bait collector education programme was proposed. Additionally, the Group suggests that an up to date survey of crab tile numbers and locations and worm digging locations alongside an impact study would allow rational decisions to be made on the need for zoning, controls or permitted growth areas. It recommends using horizontal tiles, rather than shelters embedded at an angle in the shore, and appropriate materials and colours to minimise their visual impacts. Finally, collectors are reminded to use public rights of way to access the foreshore, seek landowners’ permission elsewhere, and to consult landowners for permission to place shelters on the shore. Dialogue between collectors and property owners should be encouraged to minimise conflict.

In the Fowey estuary, the Harbour Commissioners discovered that about 300 car tyres had been placed illegally in one area, and 900 plastic drains in another. These were a potential danger in navigational areas and anchorages, and had to be removed. The code of conduct produced by the National and Cornish Federations of Sea Anglers was circulated widely, and articles run in local newspapers. In November 1998 the Fowey Harbour Commissioners put out a public notice concerning the ‘laying of or placing hazards to navigation traps and other obstructions foreshore and fundus’. This stated that any objects laid on the foreshore or fundus will be removed forthwith. As owners of the foreshore and fundus in the estuary, the Harbour Commissioners ‘advise persons wishing to establish fishing traps and other fish farming methods that a license needs to be obtained to carry out such operations. Such licences will only be issued having due regard to the environment of the estuary and after consultation with other users and statutory authorities. The licenses to be issued by the Harbour Commissioners will be able to take account of physical carrying capacity, specify the type of structure, and require details of catches to be returned’ (M.J. Sutherland pers. comm.). Areas licensed for crab shelters may be marked on charts, and on the ground with beacons, if necessary (this has been undertaken for shellfish farms). The Fowey Estuary Management Plan (progress report November 1998) noted that communication would be sought between the fishermen and the Harbour Office and other interested parties to establish a Voluntary Code of Practice for the Estuary, as achieved on the Tamar.

Crab shelters have recently been installed in large numbers (about 12,500 tiles were counted in March 1999, Russell 1999) in the Teign Estuary, where they are installed at an angle in very soft mud and are highly visible from vantage points. In addition to the aesthetic effect, this activity also caused conflicts with individuals wishing to access their moorings or launch craft, and shellfish farmers visiting their farm sites. Teignbridge District Council has led a voluntary approach to regulation in this estuary. A User Group (River Teign Bait Collectors Association, predominantly of commercial and hobby collectors) has been set up with an agreement to adhere to the Draft Code of Conduct (below), including a moratorium on the introduction of new tiles. The great majority of crab collectors are members of this group,though reportedly a few are not. Overall, the estuary management plan is seen as having been extremely effective at addressing this issue. However, agreement may have been aided by the existence of legal powers of landowners to remove shelters (The Crown Estate own the whole foreshore, but lease areas to TDC, the Harbour Commission and Devon Wildfowlers Association), and fisheries legislation that is potentially able to regulate the fishery if required.

Draft code of conduct

Crab pots, River Teign

This is a voluntary code of conduct agreed between Teignbridge District Council and the River Teign Bait Collectors Association who regulate the use of crab pots on the River Teign.

  1. No further crab pots shall be placed on the bed of the River Teign other than in the same location, and as replacements for, those in position on the 1st April 1998.
  2. All those crab pots sited in the vicinity of public slipways which are in such a position as to cause difficulties to those landing and retrieving boats from those slipways shall be removed.
  3. All those crab pots sited within the swinging arc of existing licensed moorings shall be removed. Provided that if the swinging arc is increased either by the use of a longer mooring or as a result of placing a larger boat on the mooring, then there shall be no obligation to remove the crab pots placed within this increased arc.
  4. In the even that mooring positions are reorganised so that a number of boats are moved to a single trot, the provisions in 3 above shall apply to the siting and removal of crab pots in the vicinity of the new mooring positions. Before any such reorganisation of moorings which would require the removal of crab tiles the Council will consult the River Teign Bait Collectors Association.
  5. No crab pots shall be placed within X metres of oyster beds or mussel beds and there shall be left a means of access on foot from each oyster bed and mussel bed within a width of at least Y metres to the shore.
  6. All crab pots must be correctly positioned, that is to say that they must be placed at such a low angle so as to ensure that they do not cause difficulties for other river users and in any event no crab pots shall be more than 20 cm in height.
  7. No crab pots shall be of a material which could affect the quality of the water to the detriment of fish in the river.

As crab shelters have been removed and numbers reduced in each estuary where controls have been implemented, there has been a tendency for the collectors to move further east along the coasts of Cornwall and Devon. Additionally, anglers and commercial collectors are beginning to express an interest in commencing this activity further afield (for example in Milford Haven and on the Lancashire coast). The success of future voluntary controls will very much depend on the ability of regulators to identify a local group of collectors, and this group being strong enough to deal with activities by ‘outsiders’, particularly those individuals viewed as a ‘rogue element’ moving along the coast from estuary to estuary.

Acknowledgements: David Rowe, National Federation of Sea Anglers; Colin Davies, South West Federation of Sea Anglers; Tim Robbins, Devon Sea Fisheries Committee; Natasha Barker, Teignbridge District Council; Mike Sutherland, Chief Executive and Harbour Master, Fowey Harbour Commissioners; Jo Crix, English Nature; and Philip Gibbon.

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