Use ‘mussel socks’ to prevent birds from attacking shellfish

Overall effectiveness category Likely to be beneficial
Number of studies: 1
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How is the evidence assessed?

Effectiveness

50%
Certainty

41%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

‘Mussel socks’ are protective netting materials designed to reduce predation by birds on shellfish. The socks are made from polypropylene material with a biodegradable layer sown around it. The second layer (which has smaller mesh openings) prevents mussels from migrating towards the outside of the sock in order to filter feed and so reduces the threat from predation. The mussels are buffered between these layers over winter until the following spring when the protective layer decomposes and allows mussel growth to continue unhindered.

Key messages

A randomised, replicated controlled experiment in Canada found that fewer medium-sized mussels were taken from mussel socks with a protective ‘sleeve’, compared to un-sleeved socks. There were no differences for small or large mussels.

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 randomised, replicated controlled experiment in October 2002 in three bays on Prince Edward Island, Canada (Dionne et al. 2006), found that mussel socks with a ‘sleeve’ of a biodegradable cotton-polyester mesh lost fewer medium-sized (20 mm) mussels to greater scaup Aythya marila predation than un-sleeved socks. Losses were similar for small (14 mm) and large (26 mm) mussels, but more small mussels migrated through sleeved socks (thus more vulnerable to predation).
Study and other actions tested
Referenced paper
Barbeau M.A., Hamilton D.J., Lauzon-Guay J. & Dionne M. (2006) Protective socking material for cultivated mussels: a potential non-disruptive deterrent to reduce losses to diving ducks. Aquaculture International, 14, 595-613.

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
Disturb birds using foot patrols Action Link	Unlikely to be beneficial	2	Synopsis Link
Use netting to exclude fish-eating birds Action Link	Likely to be beneficial	6	Synopsis Link
Use ‘mussel socks’ to prevent birds from attacking shellfish Action Link	Likely to be beneficial	1	Synopsis Link