Fishtraps were one of the more common monuments recorded along the survey area in the intertidal zone. Fishtrap sites have been recorded in English, Welsh and Irish estuaries and further research would aim to complement previously known sites.
The fishtraps recorded during the survey were found in the intertidal zone between Mean High Water Mark (MHWM) and Mean Low Water Mark (MLWM). They are concentrated in two locations; the Beauly Firth and the Cromarty Firth, situated on shallow gradient mud or sand flats. They were built during the 17th-19th centuries to catch fish, especially salmon that were abundant in the Inner Moray Firth. Seasonal runs of migratory salmon and sea trout swim through marine river channels that at low water often act as holding pools. The fish would then use the ebb or flood tide to progress further down or upstream. The traps were placed at right-angles or oblique to the channels so that the fish could be prevented from continuing their journey. Subsequently as the tides fall the fish would be forced into the angles of the traps where they would be unable to swim upstream or towards MHWM and could then be caught with hand nets or in static nets.
Three different types of fish trap have been identified from documentary evidence: yairs, stake nets and bag nets. Yairs are curvilinear stone or wooden structures that run perpendicular to the shoreline and curve, usually upstream, to form a bent arc. Wooden stakes interwoven with wattle have been recorded in some yairs, which show complex wattle and stake features at points along their length. Other yairs have been recorded with zigzag plans, designed to trap fish on both the ebb and the flood of the tide. Stake net traps comprise lines of stone mounds into which wooden stakes were driven and between which nets were strung. The third group of fish traps are bag nets, comprising single lines of nets with stakes at either end, usually at MLWM. Evidence of these traps were found as single mounds in the survey area.
Sixty two fish traps were recorded in the survey area, compared with over 70 sites marked on cartographic sources dating between 1817-1909. Although the variation is not necessarily significant because it does not define the time-depth of individual monuments, it does indicate that the survival of these monuments is dependent on environment and situation. The surviving sites are located in sheltered situations in the Beauly Firth, Munlochy Bay and the Cromarty Firth and there are remains found on the rocky shorelines in between these firths and bay. All of the sites recorded were found to be in poor condition, probably caused by the effects of coastal erosion and/or accretion.
It is recommended that all sites identified as fishtraps that are currently effected by active erosion should be surveyed as soon as possible. The final loss of these remains is imminent and they should be subjected to detailed analysis.