126 Mussel Beds; their Productivity and Maintenance 



The Dovey Estuary (see Map). 



It is necessary to give here a brief description of the Dovey Estuary, 

 and of its mussel beds. 



The estuary is a large inlet (some five miles in length), which divides 

 the counties of Merionethshire and Cardiganshire. Its area is approxi- 

 mately five and a half square miles. The north shore is rocky and 

 steep, but, on the south, it is bounded by that low-lying tract which 

 we may term the Dovey Flats. A large sand bar lies across the entry 

 of the estuary, and restricts it to a relatively narrow channel or neck. 

 Such an estuary is termed a "bottle-neck." Within, its condition may 

 best be described as sand-logged, and, consequently, with the exception 

 of the actual channel (or channels) of the river, it is very shallow. 

 Through the great stretches of sand, the river pursues a meandering 

 course to its outlet. Its channel is subject to considerable alteration 

 from time to time, through the agency of the banks of shifting sand. 

 The stable sandbanks are populated by an abundance of cockles and their 

 associates. 



Although relatively shallow, it is yet obvious that a very large 

 volume of water is contained in the estuary at high tide. This, having 

 to ebb and flow through one comparatively narrow outlet, is apparently 

 never wholly changed ; for instance, within the estuary, the tide will 

 have risen appreciably before it is able to check the outgoing current. 

 Therefore matters constituting a possible source of contamination to 

 the mussels may remain in the channel for a long time. 



The river impinges at several points on the north shore, including 

 nearly the whole of that portion fronting the town of Aberdovey and its 

 neighbourhood, and westwards to the Wharf. The current formerly 

 ran along the shore from Trefri to Penhelig Point (east of Aberdovey), 

 but, at the present time, only a shallow gutter marks this old channel. 

 For the most part, these places have been cleared of sand, and they are 

 either rocky, or else covered with stony beaches. This portion of the 

 foreshore shelves moderately gently to low-w^ater mark of spring tides, 

 and then very abruptly to the bed of the river. It is upon such rocky 

 andstony areas (from aboutlow- water mark of ordinary tides downwards), 

 here of limited extent, that the mussel beds are situated. The sea 

 mussel needs hard ground on which to anchor itself; but, where the 

 current is not very swift, and there is a muddy bottom (as at Portmadoc), 

 they are able to maintain themselves by becoming embedded in the 

 mud, or by clinging to each other in clusters. 



