Use methods to dampen underwater noise emissions (e.g. bubble curtains, screens)

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

50%
Certainty

30%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Activities that produce large amounts of underwater noise, such as seismic airgun surveys, pile driving, dredging, explosives and sonar, may disturb or cause auditory injury to marine and freshwater mammals (Gordon et al. 2003, Bailey et al. 2010). Various methods may be used to dampen underwater noise emissions. This may involve surrounding the sound source with devices to absorb energy, such as screens or physical barriers, bubble curtains (a ‘curtain’ of air bubbles), hydro-sound dampeners (nets with gas-filled balloons and foam attached), cofferdams (insulated sleeves) or a combination of these measures (Verfuss 2014).

Bailey H., Senior B., Simmons D., Rusin J., Picken G. & Thompson P.M. (2010) Assessing underwater noise levels during pile-driving at an offshore windfarm and its potential effects on marine mammals. Marine Pollution Bulletin, 60, 888–897.

Gordon J., Gillespie D., Potter J., Frantzis A., Simmonds M.P., Swift R. & Thompson D. (2003) A review of the effects of seismic surveys on marine mammals. Marine Technology Society Journal, 37, 16–34.

Verfuss T. (2014) Noise mitigation systems and low-noise installation technologies. Pages 181–191 in: Federal Maritime and Hydrographic Agency, Federal Ministry for the Environment, Nature Conservation & Nuclear Safety (eds.) Ecological Research at the Offshore Windfarm alpha ventus: Challenges, Results and Perspectives. Springer, Wiesbaden.

Study locations

Key messages

One study evaluated the effects on marine mammals of using bubble curtains or screens to dampen underwater noise emissions. The study was in the North Sea (Germany).

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (0 STUDIES)

BEHAVIOUR (1 STUDY)

Behaviour change (1 study): One before-and-after, site comparison study in the North Sea found that using bubble curtains or screens during pile driving resulted in harbour porpoise detections within 15 km decreasing less compared to before pile driving than at sites without bubble curtains or screens.

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 before-and-after, site comparison study in 2010–2013 at seven wind farm construction sites in the North Sea, Germany (Brandt et al. 2018) found that using bubble curtains or screens resulted in harbour porpoise Phocoena phocoena detections within 15 km decreasing less compared to before pile driving than at sites without bubble curtains or screens. Compared to 24–48 h before pile driving, porpoise detections at distances of 0–15 km from piling sites decreased less during pile driving with bubble curtains and screens (0–5 km: 63%; 5–10 km: 23%; 10–15 km: 17%) than during pile driving without curtains or screens (0–5 km: 80%; 5–10 km: 55%; 10–15 km: 50%). In 2010–2013, pile driving was carried out at seven wind farm sites with or without bubble curtains (air bubbles released from a hose on the sea floor) or screens (double-wall screen filled with air). One site constructed all of 30 foundations with screens. Five sites constructed most foundations with bubble curtains (30–79 with; 1–11 without), and one site constructed most without (1 with; 80 without). All seven sites also used acoustic deterrents (pingers and seal scarers) prior to pile driving and ‘soft-start’ procedures. Acoustic data loggers attached to moorings recorded porpoise echolocation clicks at multiple locations at all seven sites 24–48 h before and during each of 581 pile driving events.
Study and other actions tested
Referenced paper
Brandt M.J., Dragon A.C., Diederichs A., Bellmann M.A., Wahl V., Piper W., Nabe-Nielsen J. & Nehls G. (2018) Disturbance of harbour porpoises during construction of the first seven offshore wind farms in Germany. Marine Ecology Progress Series, 596, 213-232.

Please cite as:

Berthinussen, A., Smith, R.K. and Sutherland, W.J. (2021) Marine and Freshwater Mammal Conservation: Global Evidence for the Effects of Interventions. Conservation Evidence Series Synopses. University of Cambridge, 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:

Marine and Freshwater Mammal Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Delay or cease operations if marine and freshwater mammals are detected within a specified zone Action Link	No evidence found (no assessment)	0	Synopsis Link
Limit, cease or prohibit the use of sonars Action Link	No evidence found (no assessment)	0	Synopsis Link
Use methods to dampen underwater noise emissions (e.g. bubble curtains, screens) Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link