Menai Strait / Traeth Lafan

January 2004

The Menai Strait is the site of the largest on-bottom, commercial cultivation of mussels in the UK. At the eastern end of the Strait lies Traeth Lafan, an area of intertidal sandflats designated as a Special Protection Area because of its large population of overwintering oystercatchers.

Issues

Is it possible to identify new mussel-management practices that can reduce losses of mussels to oystercatchers, thereby increasing commercial profitability. What would the effect of such management be on the oystercatcher population.

Modelling

A model was developed incorporating the quantity, quality and tidal availability of mussels on naturally occurring mussel beds and commercial mussel lays. The model also incorporated the commercial shellfish gathering activities, and the oystercatcher population.

Results

The model accurately predicted the losses of mussels to oystercatchers on the commercial lays. This equated to one fifth of the value of the current commercial landings. Losses of harvestable mussels to oystercatchers can be substantially reduced by altering the shore-level and extent of the commercial lays. If younger mussels are sacrificed, reduced losses of large, harvestable mussels need not increase the oystercatchers’ mortality rate.

Funding and Collaboration

Natural Environment Research Council, University of Wales, Bangor, Myti Mussels Ltd., Deep Dock Ltd.

Related Paper:

Caldow, R. W. G., Beadman, H. A., McGrorty, S., Stillman, R. A., Goss-Custard, J. D., Durell, S. E. A. le V. dit, West, A. D., Kaiser, M. J., Mould, K. & Wilson, A. (2004) A behavior-based modeling approach to reducing shorebird-shellfish conflicts. Ecological Applications, 14, 1411-1427.