Understanding the effects of underwater noise on marine animals

Project leader

Professor M J Downie, Professor M Bentley, Dr R Perez-Dominguez, Professor A D Hawkins, Dr J Nedwell

Dates

October 2009 to August 2013

Sponsors

DEFRA

Partners

Institute of Estuarine and Coastal Studies, University of Hull, Loughine Ltd, Subacoustech Environmental Limited

Description

Underwater sound is an important feature for marine animals. Several species use sound to communicate for reproduction. They use sound for feeding and navigation over a wide range of frequencies.

Human activities add sounds to the aquatic environment. These activities include recreational and commercial navigation, off-shore exploration and developments and fisheries.

Much of the technology contributing to ocean noise is new. The sounds generated are very different to natural sounds. Both in their amplitudes and characteristics.

The SoundWaves Research Consortium aims to tackle this challenge. It concentrates recognised UK expertise on the impact of man made underwater noise into a single team.

The consortium aims to understand how individuals and populations respond to changing environments. In relation to increasing anthropogenic noise levels.

What is the problem?

UK’s marine environment provides habitat for a rich marine community.  We have the obligation to ensure its conservation and uses.  Underwater noise in the sea is increasing. 

These and other activities are leading to higher levels of ambient noise:

• Shipping
• Offshore construction
• Dredging
• Seismic surveying for gas and oil

The effects of this additional noise upon marine life are poorly understood.  At one extreme, the high level impulsive sounds from pile driving may kill or injure animals.  Other sounds may result in animals leaving a preferred area. Sustained noise may affect the ability of animals to detect their own calls, or the sounds of predators or prey. 

We need to protect and ensure the continuing presence of a rich diversity of fauna in our territorial seas.

But to do this requires research on adverse effects of underwater sound upon marine fauna. This project will address this need. It will help ensure that the ecological status of our seas is not impaired by our noisy activities.

What are the aims of this project?

The overarching aim of this project is to provide an evidence-based tool. This tool forecasts effects of anthropogenic noise on marine animals. It uses state-of-the-the-art methods and a range of expertise within a multidisciplinary framework. The project intends to achieve this aim by meeting the following five objectives:

• To review marine sound pollution with specific references to noise levels in connection with known effects on marine biota and especially fish and crustaceans.
• To develop ways of describing more precisely the characteristics of a range of noise polluting activities.
• To apply underwater observation methods to produce experimental evidence on the response of wild, naive fish to noise exposure sources under natural conditions in the sea.
• To define those exposure levels which lead to significant biological responses (injury, avoidance behaviour, startle responses).
• To produce evidence on any significant impacts of underwater noise and how these might be reduced or eliminated.

Which policy areas will the research inform?

The Marine Strategy Framework Directive member states must develop strategies. Strategies to achieve good environmental status of marine waters. 

This research will assist the UK in developing such a strategy. It ensures that the pressure of noise-making activities is within a certain threshold. It keeps them within levels compatible with the achievement of good environmental status. 

The research will also assist in supporting Marine Planning. Informing licensing applications in the UK’s territorial seas and estuaries.

What are the results from the project and how will they be used?

The research proposed in this study addresses shortcomings in present knowledge. It allows DEFRA to make informed decisions in the field of underwater acoustics. Also decisions in the effects on marine biota and ecosystems. The outputs of this programme will generate the experimental data.

These data are necessary to forecasting direct effects on important UK fish species.

These species include:

• Herring (Clupea harengus)
• Bib (Trisopterus luscus)
• Dab (Limanda limanda)
• Crustaceans including the edible crab (Cancer pagurus)
• European lobster (Homarus gammarus)

The project investigates the sensitivity of the European lobster to anthropogenic underwater noise. It is the subject of current preliminary investigation.

Activities conducted as part of this project include:

• Produce a technical review of marine sound pollution. With specific reference to noise levels and their known effects on marine biota at the onset of the program.
• Develop the most appropriate acoustic metrics to summarise a range of noise polluting activities.
• Undertake a modelling exercise. The exercise links the actual hearing abilities of model species with the noise signature of various noise polluting activities. This identifies and scores those activities posing greatest risks; estimating potential thresholds leading to responses and impacts.
• Develop underwater observation techniques (UWTV, sonar tracking). These produce experimental evidence of the responses of fish and crustaceans. It exposes wild animals to controlled noise exposure under real field conditions.
• Define those exposure levels leading to significant responses. Define thresholds for those responses:
• injury
• avoidance behaviour
• startle responses (expressed in appropriate acoustic metrics)
• Forecast effects on fish and shellfish populations
• Provide an ecological quality assessment of the impact of noise on marine fish and crustaceans.
• Produce a technical review. Summarising any loss of ecosystem functionality and integrity following exposure to underwater noise.

These deliverables will ensure the integration of concern over the impact of underwater noise upon marine life.

This includes the different policies, agreements and legislative measures. These moderate the effects of our activities upon the marine environment. Observing the impact of sounds on pelagic fish in the sea by means of sonar.

We have developed techniques for observing the behaviour of schools of fish in mid water. We do this with echo sounders and side-scan sonar. 

We developed methods for presenting sounds to the schools, monitoring the sound levels and observing the effects.

Observations were on daily and seasonal changes in the behaviour of the schools. Experiments have begun to examine the effects of sound presentation upon the schools. 

Responses of the fish schools to sounds have been variable.  We observed strong responses to pile driving in one instance. Such as fish diving and spreading out and the school breaking up. In other instances there has been no response. The reasons for these differences are being investigated.