Play predator calls to deter mammals from fishing gear

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

Effectiveness

0%
Certainty

20%
Harms

10%

Calculating overall effectiveness category

Background information and definitions

Playing predator calls may deter marine and freshwater mammals from fishing gear. This may reduce the risk of mammals becoming entangled or captured in gear, as well as human-wildlife conflict resulting from mammal predation on fish catches. Caution is required, as this intervention may cause stress to mammals and could have negative impacts on mammal behaviour and habitat use.

Study locations

Key messages

One study evaluated the effects of playing predator calls to deter mammals from fishing gear. The study was in the South Atlantic Ocean (Africa).

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (0 STUDIES)

BEHAVIOUR (0 STUDIES)

OTHER (1 STUDY)

Human-wildlife conflict (1 study): One study in the South Atlantic Ocean found that playing killer whale vocalisations did not deter Cape fur seals from feeding on fish catches in a purse-seine net or trawl net.

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 study in 1974 of pelagic sites in the South Atlantic Ocean, off the coast of southern Africa (Shaughnessy et al. 1981) reported that playing killer whale Orcinus orca vocalizations underwater did not deter Cape fur seals Arctocephalus pusillus from fishing nets. Results are not based on assessments of statistical significance. During two trials with a purse-seine net, all of 15–25 seals feeding in the net responded to killer whale vocalizations by diving. Some seals (48–100%) initially moved out of the net but all returned within 30 seconds. The authors report that floating two life-sized models of killer whale dorsal fins amongst the seals during one of the trials did not affect seal behaviour (no data provided). Results were similar during a trial at a trawl net (data not reported). Recordings of killer whale vocalizations (clicks, whistles, squeaks) were played back through an underwater loudspeaker. Two trials (each with 2–14 minutes of playback) were carried out by a purse-seine fishing vessel with the net pursed to a 10-m diameter. One trial was carried out by a side-trawler vessel with the ‘cod-end’ (containing fish) in the water. Observers on board the fishing vessels recorded seal behaviour during each of the three trials in 1974.
Study and other actions tested
Referenced paper
Shaughnessy P.D., Semmelink A., Cooper J. & Frost P.G.H. (1981) Attempts to develop acoustic methods of keeping cape fur seals Arctocephalus pusillus from fishing nets. Biological Conservation, 21, 141-158.

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

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Marine and Freshwater Mammal Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Use catch and hook protection devices on fishing gear Action Link	Likely to be beneficial	5	Synopsis Link
Use a smaller mesh size for fishing nets Action Link	No evidence found (no assessment)	0	Synopsis Link
Install exclusion and/or escape devices for mammals on fishing nets Action Link	Likely to be beneficial	7	Synopsis Link