Burry Inlet UK – Oystercatcher and Knot

July 2010

The Burry Inlet is a large embayment in South Wales, bordered on its south side by the Gower peninsula. More than ten thousand oystercatchers migrate from their breeding grounds to the Inlet every autumn and spend the winter there feeding mainly on cockles and mussels. The cockle beds are also exploited by shellfishermen who fish all year round using traditional hand-gathering techniques. This can lead to potential conflicts between the interests of birds and shellfisheries, most famously in the 1970’s, when thousands of oystercatchers were culled on the Burry in an attempt to reduce their impact on the cockle fishery.

Issues

There have been mussel beds in the Burry Inlet for many years, but recently mussel beds began to form on top of one of the main cockle beds. This prevents shellfishing by traditional hand-raking techniques and may also smother and kill the underlying cockles. Removing these new mussel beds, known locally as ‘mussel crumble’, would benefit cockle fishermen but might be bad for the oystercatchers, which feed on mussels as well as cockles. At the request of the Countryside Council for Wales, we developed a model of oystercatchers, cockles and mussels in the Burry Inlet and used it to determine how important the mussel crumble was for the birds.

Modelling

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Results

The model showed that the mussel crumble could be removed without affecting the oystercatchers when cockle stocks in the Inlet were high. If cockle stocks were lower than at present, the mussel crumble was more important to the birds and removing it would mean some birds would have to leave the Inlet during the winter months or face starvation.

Funding and Collaboration

Countryside Council for Wales

Related Paper:

Stillman, R. A., Moore, J. J., Woolmer, A. P., Murphy, M. D, Walker, P., Vanstaen, K. R., Palmer, D. & Sanderson, W. G. (2010) Assessing waterbird conservation objectives: an example for the Burry Inlet, UK. Biological Conservation, 143, 2617-2630.