124 Mussel Beds ; their Productivity and Maintenance 



CARDIGAN BAY AND ITS ESTUARIES. 



The following account of Cardigan Bay and its more important 

 inlets is, in the main, abridged and otherwise modified from Mr C L. 

 Walton's description in the first Report on Investigations towards the Im- 

 provetneni of Fisheries in Cardirjan Bay and its Rivers, published in 1913 

 by the University College of Wales, Aberystwyth. 



Cardigan Bay occupies a considerable portion of the west coast of 

 Wales. It is bounded on the north by the southern shores of Carnarvon- 

 shire, and its central portion comprises the entire coastlines of Merioneth- 

 shire and Cardiganshire, while its southern limit is the North Pembroke- 

 shire coast. It may be said to lie eastward of a line drawn from 

 Braich-y-Pwll in Carnarvon to Strumble Head in Pembroke, which two 

 places are distant some fifty-five miles from each other. The total 

 length of the coastline between these two points is about 140 miles. 

 The whole area is relatively shallow, the thirty fathom limit lying just 

 westward of the line mentioned above. Several causeways or spits 

 (Welsh, Sam, a paved roadway) project out to sea in the northern half 

 of the Bav, often for several miles. Their landward ends are uncovered 

 at- low water. Such are Sarn Badrig, Sarn y Bwch, and Sarn Cynfelyn. 

 High and steep cliffs bound the shores of the Bay, except where they are 

 interrupted by the numerous river valleys, and the larger estuaries. 

 We shall omit any mention of the former, as they do not concern us in 

 this place, and confine ourselves to the Estuaries in which the mussel 

 beds are found, namely the Estuary of the Glaslyn and Dwyryd rivers 

 at Portmadoc, the Mawddach Estuary at Barmouth, and the Dovey (or 

 Dyfi) Estuary at Aberdovey. It is in these places that the sea mussel 

 finds the conditions suited to its habits. Patches of mussels occur at 

 various places on the coast, where freshwater influence is felt, but, as 

 the shellfish always remain stunted in growth, they are of no economic 

 value. They might be employed to replenish depleted beds, if necessary. 



The tidal sweep, assisted by the south-westerly winds on the west 

 coast, is very strong. Where it meets the rivers, large storm beaches 

 have accumulated, and, fronting the estuaries, sand bars (and sometimes 

 dunes, as at the seaward end of the Dovey Estuary). This tidal sweep 

 causes great alteration of the beaches from time to time, the stone and 

 shingle being transported in a northerly direction along the coastline. 

 C. L. Walton has shown how this factor has had an adverse effect on the 

 fauna in certain parts of Cardigan Bay^. 



^ "The Shore Fauna of Cardigan Bay," Journal of the Marine Biological Association 

 of the United Kingdom. Vol. x, No. 1, November, 1913. 



