Summaries of reviewed publications – references 11 – 15.

Details are limited to information relevant to the UK marine habitats and species listed in the Habitats Directive and the Birds Directive.

[pr] indicates that the paper is from a peer reviewed journal or report


Natura 2000 Habitats & Species

Fishing Technique




REF: 11

Shallow inlets and bays


(Area of coarse sand, gravel and broken shell)

Beam trawling

Experimental 4m commercial pattern beam trawl fitted with chain matrix and 8cm diamond mesh cod-end. Towing speed 2m s-1. Initially trawl lines fished 3-4x in succession repeated after 2 hours.

Species and community effects - Gurnards and whiting aggregate over beam tracks to feed on animals damaged by the beam trawl or on other scavengers that are attracted to the trawled area. There was a particularly clear increase in the proportion of the amphipod Ampelisca spinipes in their diets and some mobile invertebrate scavengers such as Pandalus spp. only occurred in diets after the area was fished. Number of prey items eaten by gurnards and whiting increased after trawling. Dogfish did not increase their intake after trawling but did take Pandalus spp. and Crangon spp. only after the area had been trawled.

Results suggest that fish rapidly migrate into the area to feed. Additional resources such as those made available by trawling, may favour certain species that exhibit opportunistic feeding patterns such as gurnards and whiting.

Off east coast of Anglesey

Kaiser M.J. & Spenser B.E. (1994). Fish scavenging behaviour in recently trawled areas. Marine Ecology Progress Series. 112: 41-49


REF: 12


Shallow inlets and bays

Scallop dredging

Oyster dredging

Pilot survey of reefs subject to bottom trawling/dredging on a variety of seabed types; flint shards; sand, broken shell and dead maerl; sand, gravel, broken shell and dead maerl overlain with cobbles and small rocks; reef of mudstone ledges.

Clear differences in epifaunal communities between areas considered to be worked by mobile fishing gear and those not, however different sediment types in these areas is another influence. Reefs highly vulnerable to removal of epifauna and erosion caused by the action of the gear. Reefs with large boulders or severe topography which prohibits the use of fishing gear considered to be self protecting. Complex areas of sandy pockets, cobbles and boulders the size of which do not prohibit the use of rock hopper or spring loaded dredges, which support slow growing and numerous hydroids, anemones and corals, bryozoans, tunicates and echinoderms particularly vulnerable to highly mobile fishing gear. Recolonisation and recovery likely to be slow. Potential loss of productivity, habitat, and food caused by highly mobile fishing gear, may lead to the direct mortality of commerciality exploitable reef dwelling species.

Lyme Bay

Devon Wildlife Trust (1993). Lyme Bay: A report on the nature conservation importance of the inshore reefs and the effects of mobile fishing gear. Survey report carried out by the Devon Wildlife Trust.

REF: 13


Mudflats and sandflats

Inlets and bays



Changes in the balance of the benthos, particularly the loss of Sabellaria reefs and oyster beds attributed to over-fishing and trawl damage. Comparable shifts in dominance with certain polychaete species commonly favoured over more vulnerable groups such as echinoderms anticipated at regularly fished sites, and is, in principal, reversible. Recent trend towards the deployment of larger, heavier demersal fishing gear enhances the possibility of benthic changes in intensively fished areas. Shrimp fishery in Wadden Sea observed a long term decline in the number of by-catch species notably Carcinus and Pomatoschistus spp. Biomass of by-catch remained constant with compensating increase in dab, sprat and cod.

North Sea

Rees H.L. and Eleftheriou A. (1989). North Sea benthos: A review of field investigations into the biological effects of man’s activities. J. Cons. Int. Explor. Mer. 54(3): 284-305


REF: 14


Shallow inlets and bays


Experimental study on the effects of Nephrops creels and lobster and crab pots on benthic habitats and communities in a number of locations/habitats. Quantitative effects of one month’s fishing using crab and lobster pots.

Species and community effects - Sites in Scotland - Descending creels build up a small pressure wave which caused the sea pens Pennatula phosphorea, Virgularia mirabilis and Funiculina quadrangularis to bend before the creel made contact. This removed the tip of the sea pen from damage through impact. After smothering or uprooting all three species reinserted and uprighted themselves when in contact with muddy substrate. No lasting effects on muddy substrates. Devon/Wales - Rocky substrate habitats and communities at a depth no deeper than 23m below chart datum subjected to lobster and crab potting relatively unaffected by fishing activity. Experimental and control plots 30mx12m in Devon and 50mx20m in Wales. Pentapora foliacea found broken after hauling although unclear whether this was due to fishing. Eunicella verucosa bend under the weight of pots and then return to an upright position afterwards. Slow growing and long lived Eunicella verucosa previously considered highly vulnerable to damage. One month’s active fishing using crab and lobster pots caused no difference in abundance of species between control and experimental study plots. Abundance of some species increased after potting in comparison with their abundance before potting. Potting did not have a detrimental effect on the abundance of species studied.

Experimental simulation of 12 lost parlour pots revealed that they may actively fish for up to 270 days and remain baited for between 8 and 27 days. Catch rates highest during first month. Brown crab catches showed slight temporary decrease after bait depleted and subsequently fairly constant. Spider crab catch declined steadily. In time condition of the catch deteriorate, wrasse showed skin damage and limb loss increased markedly the longer crustaceans remained in the pot. Incidental observations in the vicinity of the pots shows several had moved over and broken Pentapora colonies. Pots moved down the gently sloping seabed until constrained by mainline tightening.

Loch Broom, Bardentarbot Bay, Lyme Bay, Skomer, Pembrokeshire coast.

Eno N.C., MacDonald D.S. & Amos S.C. (1996). A study on the effects of fish (crustacea/mollusc) traps on benthic habitats and species. Report to the European Commission.

REF: 15


Mudflats and sandflats

Mechanical cockle dredging

Experimental investigation on the effects of cockle dredging on spat settlement using a 71cm mechanical dredge with revolving riddle.

Species and community effects - A single pass of the dredge reduced both fishable and juvenile stocks of cockles substantially. Adult cockles more damaged by dredge than juveniles. No subsequent difference in cockle mortality between dredged and undredged plots. New spat settlement not affected.

Burry Inlet

Walker P. Cotter A.J.R & Bannister R.C.A. (1995) A preliminary account of the effects of tractor dredging on cockles in Burry Inlet, South Wales.


Next Section