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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 Goddens 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- No crab pots shall be of a material which
could affect the quality of the water to
the detriment of fish in the river.
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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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References
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