Coastal fish weirs at West Mersea, 570m south east of St Peter's Well


Heritage Category: Scheduled Monument

List Entry Number: 1019104

Date first listed: 06-Oct-2000


Ordnance survey map of Coastal fish weirs at West Mersea, 570m south east of St Peter's Well
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The building or site itself may lie within the boundary of more than one authority.

County: Essex

District: Colchester (District Authority)

Parish: West Mersea

National Grid Reference: TM 00995 11957


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

Coastal fish weirs are artificial barriers created within the inter-tidal zone, using stone walls, wattle or timber fencing to channel fish into traps. The most common form of weir (a term derived from `were' - an Anglo-Saxon word meaning fish trap) is a simple `V'-shaped arrangement of walls, frequently 100m or more in length. Baskets or nets would be placed at the point of the `V' which would normally be orientated seaward so as to draw in the fish with the receding tide. Weirs may also be rectangular or more linear in appearance with traps located either in corners or set within spurs attached to the main walls. Placed in gently shelving coastal or estuarine locations, the weirs would become sufficiently exposed at low water for the fish to be collected and, in some instances, for initial processing (gutting, filleting) to take place on site. Stationary fish traps are known to have been used since the Mesolithic period, although the earliest examples to leave strong visible traces around the coastline belong to a tradition dating from the early medieval or Anglo-Saxon period. Documentary evidence from the 10th century onwards suggests that fish weirs were largely the preserve of the upper echelons of medieval society, maintained either by larger manors or by religious houses. In addition to the obvious advantage of a constant food supply, the produce from the fish weirs provided economic benefit, indicated social status and could aid compliance with the religious dietary strictures of the period. Large fish weirs were still used in the Severn Estuary until the early 20th century, and their small-scale use persists here and in other parts of the British Isles to this day. In general, however, the practice reached its peak between the 12th and 14th centuries, hereafter declining in the face of growing commercial sea fishing. The remains of about 500 fish weirs are estimated to survive around England's coast. Those of medieval or earlier date which demonstrate a high degree of preservation, and particularly those which form groups or have demonstrable links with manorial or ecclesiastical estates, will normally be considered to be of national importance and worthy of protection.

The coastal fish weirs at West Mersea, 570m south east of St Peter's Well, are well preserved and may be an example of an unusual double weir should the two elements of the structure prove to be contemporary. Aerial reconnaissance shows the timbers as well-preserved, with large sections protruding out of the mud; this will facilitate further analysis including timber sampling for radiocarbon dating, should the site be exposed in future seasons. The weir may well be one of three fisheries mentioned as existing at Mersea Island in the Domesday Book. It is certainly considered to be early medieval in origin, similar to several other fish weirs which have been identified through recent archaeological studies of the Blackwater Estuary. Elsewhere, the age of timbers has been established by radiocarbon dating, and in some cases shown to be as early as the seventh century AD. It is quite possible that fish processing remains are preserved within the monument, most probably in and around their elongated traps or pounds. Similar fish traps at other Blackwater Estuary weirs have been found to contain extensive fishbone deposits which may have a direct bearing on the range of activities originally carried out on site. The West Mersea weir is clearly capable of similar investigation, and further comparative study between this site and others in the estuary is expected to provide significant insights into the overall date range, development and relevance of these weirs to the social structure and economy of the early medieval period.


Legacy Record - This information may be included in the List Entry Details.


The monument includes two V-shaped timber weirs, one constructed inside the other, located near the northern shore of the Blackwater Estuary to the south of the town of West Mersea, some 300m beyond the main sea wall. The complex was first recorded from the air in 1993, during a period of very low tides. The outer weir has walls with a width of 85m (north west-south east) and 110m (north east-south west). The inner weir has walls with a width of 100m (north west-south east) and 110m (north east-south west). The outer weir has two further short lines of timbers on the outside of and running parallel to its south western side; the inner weir has three short lines of timbers running parallel to its main wall. These additional timber alignments probably represent successive modifications to the design. The two weirs both have very elongated trap areas at their easternmost points; these would have housed the nets, and fish remains and processing deposits are expected to survive in and around them. The site is situated just below Mean Low Water and is now largely sub-tidal.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 10 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number: 32402

Legacy System: RSM


Books and journals
Rumble, A , Domesday Book, 32 Essex, (1983)
Strachan, D, C14 dating of some inter-tidal fish-weirs in Essex, (1997), 6
Strachan, D, TM01SW 1:10000 plot, (1996)
Three black-and-white frames, Bruce, K, KBC10,11 and 17, (1993)
Two black-and-white frames, Rogers, P, SWBW 14-5,6; SWBW 15-11,12, (1993)
Two colour prints, Strachan, D, CP/97/5/8,9, (1997)

End of official listing