Ziggy Otto1, Phil Coates2, Bill Sanderson1, Andy Woolmer2 & Clare Eno1

1. Countryside Council for Wales (CCW), Maes-Y-Ffynnon, Bangor,Gwynedd, LL57  2DN, Wales, UK.
2.  South Wales Sea Fisheries Committee (SWSFC), Queens Buildings, Cambrian Place, Swansea, SA1 1TW, Wales, UK.

The Countryside Council for Wales (CCW), as statutory advisor to the Welsh Assembly Government, and the South Wales Sea Fisheries Committee (SWSFC), as regulatory fisheries body, are currently working closely together to ensure the sustainable management of these fisheries, within the constraints of the legislative framework currently in place.

Figure 1.  Map of the Carmarthen Bay & Estuaries Special Area of Conservation, the Burry Inlet Special Protection Area, and their cockle fisheries.  

The Burry Inlet cockle fishery

Since 1965 the fishery has been managed by the South Wales Sea Fisheries Committee (SWSFC) under a Regulating Order made under the Sea Fisheries (Shellfish) Act 1967, which allows the issue of a restricted number of licences.  Throughout the history of the fishery, only hand raking has been allowed, although access is now allowed by vehicle rather than restricted to horse and cart or donkey.  Fishery effort is tightly controlled by the SWSFC via the issue of cockle licences and daily quota.

A limited number of licences (ca. 50) are issued each year for the hand raking of cockles only.  Gathering takes place all week except on Sundays to an individual daily quota of 300 kg - 600 kg (0.3 - 0.6 tonnes) per person per day.  Minimum cockle sizes (17.5mm or 19mm square gauge) are determined via hand riddle size to allow the survival of sufficient spawning stock.  Scientific assessment of the cockle biomass takes place at least once per year by scientists from SWSFC and/or CEFAS (Centre for Environment, Fisheries and Aquaculture Science).  From these surveys the level of fishable stock is set at around 33 % of the total fishable biomass.  The number of cockle licences (full time or temporary) and daily cockle quota is then broadly set to give rise to the desired fishing effort.  As a rule of thumb, the taking of a third of the biomass of adult standing stock each year has proved its worth in the Burry Inlet as a stock conservation rule, and is now being applied to other fisheries, i.e. 33 % to the fishermen, 33 % for bird food, and the remaining 33 % to act as brood stock in order to sustain the fishery.

The Burry Inlet cockle fishery has been recognised by a Marine Stewardship Council (MSC) accreditation, the only molluscan fishery in the world so far to receive such an accolade (MSC, 2006).  Independent certifiers have found that its management gives rise to a sustainable fishery in both fishery and ecological terms which reflects social good practices. 

Three Rivers Estuary cockle fishery 
Cockle stocks in the neighbouring Three Rivers Estuary are naturally more variable than in the Burry Inlet thereby setting management challenges.  The level of harvestable cockle here is via the standard minimum size, gathering by hand only, and no night fishing along with seasonal opening and closure of specified beds.  Furthermore, a permit scheme is now in place which is the means by which catch returns are collected from named individuals.  Permits are available to everyone upon request, free of charge, reflecting the limit of current Sea Fishery Committee powers under byelaw.  This contrasts to the Regulating Order powers in the Burry Inlet under a separate statutory power, which allows the SWSFC Committee to restrict access by means of a chargeable licence and to recover, in full, the costs of management.

In 2005, and following an unprecedented settlement of cockles in 2004, up to 2,000 cockle gatherers fished the Three Rivers Estuary in August 2005.  8200 tonnes of cockles were removed under SWSFC permit and a gathering regime that allocated different gathering areas for each tide / day and left an area to lie closed (Figure 2).  The fishery was closed again in December 2005 under byelaw 24 which allows for ‘Temporary Closure’ for the protection of shellfish purposes.  Surveys in early April established there to be over approximately 1000 tonnes of cockles in the Three Rivers Estuary, however, these suffered a 50% mortality over the subsequent 3 months during a mass mortality event (see below).

In consultation with CCW and Carmarthenshire County Council, the SWSFC was to again open a more limited fishery in 2006 mainly based within the area left closed during 2005.  However, the cockle mortality event gave rise to temporary public health closure, following the lifting of which it was decided that these remaining cockles should be protected in order that they act as a ‘broodstock’ for the population and to provide a valuable food source for migratory birds this winter.

Figure 2.  Permitted Cockle gatherers at Llanstephan in the Three Rivers Estuary in August 2005.

Further regulation of cockle fishing effort is now being sought via a Regulating Order, akin to the one already in place for the Burry Inlet.  The requirements include the Competent Authority, in this case the Welsh Assembly Government, to undertake an Appropriate Assessment (AA) in accordance with the provisions of Regulation 48 of the Conservation (Natural Habitats, &c.) Regulations 1994.  Regulation 48 requires the Competent Authority to ascertain that this activity will not adversely affect the integrity of the EMS concerned, and if so, the AA will furthermore establish at what extent and intensity the activity can be reconciled with the Conservation Objectives for the site.  As the measure will result in better control of effort, greater accountability and therefore improved fishery and environmental management, the AA is expected to give positive results.     

Mass mortality of cockles in the Burry Inlet and the Three Rivers Estuary
In 2006, mass mortality of cockles occurred for the 4th consecutive year in both the Burry Inlet and areas of the Three Rivers Estuary, thus threatening fisheries and nature conservation interests.  The cause is not yet known, but it seems likely that it is multi-factorial with factors such as higher than usual cockle recruitment and subsequent high stocking densities, pathogens, climate change, changes in discharges and inputs all implicated.  Certainly a factor or a combination of them appears to be stressing the animals to the point of mass mortality.  Finding the cause(s) for the mass mortality is central to the management of the cockle stocks within both a fisheries and nature conservation context.

CCW and the SWSFC over the last two years have synchronised cockle and mussel stock assessment in the Burry Inlet SPA (Figures 3 & 4) and the adjacent Three Rivers Estuary where wading birds are likely to migrate. 

Figure 3.  Distribution and density of cockles (>2mm) in the Burry Inlet, with a square root transformation.  Maximum density (the largest dot) was 2501 cockles/0.1m2.  From Moore (2004).

Figure 4.  Locations and extents of surveyed mussel beds in the Burry Inlet.  From Moore (2004).

Further assessments are planned this year including low tide bird surveys to assess the distribution and behaviour of waders.  These data are essential prerequisites for developing a more holistic management of birds and their food (see below) and informing Appropriate Assessment of fishery management decisions as now required following the ECJ Waddensea Judgement (C-127/02); but there is an apparent wider research need when the mass mortalities are considered.

The CEH birdfood model
The Centre for Ecology and Hydrology (CEH), with CCW support, have developed a behaviour-based model to predict the food requirements of wintering oystercatcher and knot on the Burry Inlet SPA.  The model allows the impacts on bird survival and condition to be explored under different potential management scenarios.

Figure 5.  Maximum oystercatcher and knot populations supported by shellfish stocks on the Burry Inlet in 2004 (a) using 2001 ash-free dry mass-length relationship (b) using 2004 AFDM-length relationship. Hatched yellow bars - oystercatchers supported by cockles and mussels, yellow bars - oystercatchers supported by cockles alone; black bars - oystercatchers supported by mussels alone, pale yellow bars – knot supported by cockle spat.  Dashed line shows the most recent WeBS 5-year average count for each species.  Solid lines show SPA citation numbers.  Supplementary food was present in the form of terrestrial invertebrates in fields adjacent to the estuary.  From West et al. (2005).

Bird foraging choices can be predicted based on previous bird behaviour studies, cockle and mussel stock surveys and low-tide bird surveys.  Bird distribution changes significantly in response to poor cockle stocks: birds may switch to feed on mussels and other food sources in the Burry Inlet, or move to cockles elsewhere including the Three Rivers Estuaries.

Future modelling work will allow us to predict (and test the predictions) whether there is enough food for waders with certain stock size, meat contents and distributions.  This would help fisheries and conservation managers explore different management scenarios and their outcomes and may lead to agreed management 'rules' that ultimately cut-down on protracted interagency discussions and uncertainty.  This would move aspects of management away from a reactive approach to a more efficient pro-active approach. 

References
Judgement of the Court (07/09/2004) Case C-127/02 Landeliijke Vereniging  tot Behoud van de Waddenzee and Nederlandse Vereniging tot Bescherming van Vogels v Staatssecretaris van Landbouw, Natuurbeheer en Visserij

Marine Stewardship Council 2006.  Burry Inlet Cockle Fishery.  http://www.msc.org/html/content_486.htm

Moore, J.J. 2004. Surveys of cockle and mussel stocks in the Dee, Traeth Lafan and Burry Inlet. A report to the Countryside Council for Wales from Coastal Assessment, Liaison & Monitoring.  CCW Marine Monitoring Report No: 16, 29pp.

West, A.D., McGrorty, S., Goss-Custard, J.D., Sanderson, W.G., & Gray. C. 2005. Modelling shorebirds and their food on the Dee Estuary, Traeth Lafan and Burry Inlet SPAs to inform target setting and site management – phase 2.  A report to the Countryside Council for Wales from the Centre for Ecology and Hydrology.  CCW Marine Monitoring Report No: 19, 151pp.

The views expressed in this poster are not necessarily those of the Countryside Council for Wales or those of the South Wales Sea Fisheries Committee.

For further information please contact the authors