Discovering How Human-caused Sounds Affect Marine Mammals

Marine mammals are an important component in the food-chain of the marine biotope. They rely largely on sound for their communication and organisation, but these mechanisms are not completely understood.

The proposed research strategy is of key importance because both marine mammals and many economically important sea-based activities are at risk because of a lack of information about the effects of anthropogenic sound on marine mammals.

Human activities produce a range of underwater sound frequencies that can interfere with marine mammal functions important for their survival.

Use of sound in the ocean has increased due to a growing number of scientific and military applications (e.g. seabed mapping, naval sonar) and many economic ocean-based activities such as oil exploitation and fisheries. This concern has triggered a number of investigations on the impacts of man-made sound on marine mammals, but to date, there has been no structured analysis of the full research challenge it presents.

“A scientific research strategy is clearly needed. First of all, interaction between anthropogenic sound and marine mammals is a complex problem, as the effects of anthropogenic sound on marine mammals depend on many aspects, such as intensity and frequency of sounds, marine mammal species and their age, environmental conditions, etc. In addition, the physiological effects of sound in the oceans are not clearly understood.” says Marine Board Chair Lars Horn.

In its global assessment of cetacean species, released in august 2008, the International Union for the Conservation of Nature (IUCN) concluded that ocean noise posed a significant threat. These concerns have reached the larger public through exposure in popular press and media.

In spite of growing attention, defining and implementing measures to reduce the impacts of man-made sound on marine mammals remain seriously hindered by a lack of knowledge.

“There is a need to rapidly improve the state of knowledge by new research focussed on specific questions of high priority. This requires concerted, coordinated action across many expert groups within the scientific community” says Expert Group Chair Ian Boyd.

A key message of the Marine Board Position Paper is that a risk assessment framework needs to be used to define where the research effort can be applied with greatest effect.

The Position Paper concludes that to construct a full risk assessment, it is necessary to be able to make all the linkages between issues from sound production, through behaviour change, effects on life function and the effects on populations. In particular, there is a need to improve knowledge of how effects on life function influence vital rates.

The analysis presented in the Position Paper is a first step towards defining a full research strategy and will need further review and modification as additional intellectual attention is applied to this field.

*The research strategy presented in Marine Board Position Paper 13 results from the activities and proceedings of an Expert Group on anthropogenic sound and marine mammals convened at the joint European Marine Board and National Science Foundation (US) Workshop at Tubney House on October 4-8 2005 in Oxford, with financial and logistical support of the Marine Board.

Position paper: The Effects of Anthropogenic Sound on Marine Mammals