Deter birds from landing on shellfish culture gear by suspending oyster bags under water

Overall effectiveness category Likely to be beneficial
Number of studies: 1
Share Tweet Email

View assessment score

How is the evidence assessed?

Effectiveness

55%
Certainty

43%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Oyster bags are mesh bags, attached to floats and anchored on the seabed into which young ‘seed’ oysters are placed. They then grow and are harvested when large enough. Oyster cages are similar, but are made of rigid wire mesh.

Study locations

Key messages

A replicated and controlled study from Canada found that significantly fewer birds roosted on oyster bags suspended 6 cm below the water, compared with non-submerged bags. Birds roosted on bags suspended 3 cm below the water as frequently as control bags.

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

A replicated and controlled experiment in summer and autumn 2006 and 2007 in oyster Crassostrea virginica farms off the coast of New Brunswick, Canada (Comeau et al. 2009), found that suspending oyster bags 6 cm under the water significantly reduced the number of birds roosting on them (1 bird/100 bags on submerged bags vs. 37 on controls). However, suspending bags 3 cm below the water did not significantly reduce the number of birds roosting (15 birds roosting/100 bags).
Study and other actions tested
Referenced paper
Comeau L.A., St Onge P., Pernet F. & Lanteigne L. (2009) Deterring coastal birds from roosting on oyster culture gear in eastern New Brunswick, Canada. Aquacultural Engineering, 40, 87-94.

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

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bird Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Provide refuges for fish within ponds Action Link	Likely to be beneficial	1	Synopsis Link
Increase water turbidity to reduce fish predation by birds Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link
Disturb birds using foot patrols Action Link	Unlikely to be beneficial	2	Synopsis Link