Use electric fencing to exclude fish-eating birds

Overall effectiveness category Likely to be beneficial
Number of studies: 2
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How is the evidence assessed?

Effectiveness

60%
Certainty

49%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Predation by birds at aquaculture facilities (e.g. fish ponds, raceways and shellfish farms) can cause significant commercial loss (Draulans 1987). With increasing protective wildlife legislation, demand for non-lethal, environmentally safe methods of bird exclusion and scaring have increased. Most fish farmers now rely primarily on non-lethal techniques to accomplish control (i.e. to reduce abundance or exclude fish-eating birds in and around the vicinity of fish farms). Control efforts may be optimized by compiling evidence relating to deterrent or exclusion device efficacy, taking into account costs, practicality of use and the possibility of developing integrated strategies (i.e. combining more than one deterrent method). Avian deterrents can be categorised as auditory, visual, chemical, exclusion, habitat modification and lethal (Bishop et al. 2003). Lethal deterrents are not considered here (except where, very rarely, used as part of an integrated approach).

Bishop, J., McKay, H., Parrott, D. & Allan, J. (2003) Review of international research literature regarding the effectiveness of auditory bird scaring techniques and potential alternatives. Department for Environment Food and Rural Affairs.

Draulans, D. (1987) The effectiveness of attempts to reduce predation by fish-eating birds: a review. Biological Conservation, 41, 219–232.

Study locations

Key messages

Two before-and-after studies from the USA found that electric fencing reduced the use of fish ponds by great blue herons Ardea herodias and great egrets Casmerodius albus.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

Before-and-after trials in Mississippi, USA (Mott & Flynt 1995), found that a two-strand electric fence reduced pond use by great blue herons Ardea herodias and great egrets Casmerodius albus by 91%. Five ponds (0.3-2.2 ha in area) containing channel catfish Ictalurus punctatus were tested.
Study and other actions tested
Referenced paper
Mott D.E. & Flynt R.D. (1995) Evaluation of an electric fence system for excluding wading birds at catfish ponds. The Progressive Fish-Culturist, 57, 88-90.
A before-and-after trial in August-November 1996 in Pennsylvania, USA (Tobin et al. 1997), found that electric fencing was fairly effective in deterring great blue herons Ardea herodias from raceways (long, 3-6 m wide fish ponds) at two trout hatcheries (declines from 6-14 birds/h/day and 76-159/h/day to <3 and <58 after electric fencing was erected). Fences comprised two strands of polyethylene tape (1.6 cm wide, 15-30 cm apart). Herons were counted (4 counts/week before and after installation; additional counts to 62 days after installation). Reductions in fish predation were not assessed.
Study and other actions tested
Referenced paper
Tobin M.E., Glahn J.F. & Rasmussen E.S. (1997) Electric fencing reduces heron predation at Northeastern trout hatcheries. Proceedings of the Eastern Wildlife Damage Management Conference, 8, 16-19.

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2020) Bird Conservation. Pages 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Bird Conservation

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Deter birds from landing on shellfish culture gear using spikes on oyster cages Action Link	Likely to be beneficial	1	Synopsis Link