Impacts of anthropogenic noise on reproduction and survival

Noise-generating human activities, such as urbanisation, transportation and the exploitation of resources, have increased since the Industrial Revolution and have changed the acoustic landscape of terrestrial and aquatic ecosystems. Anthropogenic (man-made) noise is now recognised as a major component of environmental change and a pollutant of international concern; for example, it is included in the European Commission Marine Strategy Framework Directive (MSFD) and the US National Environment Policy Act, and as a permanent item on the environmental agenda of the International Maritime Organization.

Fish can use natural sounds for communication, orientation and habitat selection, but we know that anthropogenic noise can raise their stress levels and affect communication, foraging and movement. However, it is difficult to predict what this might mean for individual fitness (survival and reproduction), and thus for populations and communities. Our recent work has shown that short-term exposure to motorboat noise can affect fish anti-predator behaviour, causing a doubling in mortality when encountering natural predators, but as yet we don't know how longer-term noise exposure affects other key life-history processes.

The aim of this project is to use an established field-based study system (coral reef fish) to assess the impacts of a major source of anthropogenic noise (motorboats) on key life-history processes (reproduction, embryonic and larval survival) that have direct fitness and ecological implications. Driving boats around nests of the spiny chromis Acanthochromis polyacanthus and the Ambon damselfish Pomacentrus amboinensis, we will assess the impacts of the generated noise on reproduction and early-life survival. Subsequent experiments with captive-breeding populations will allow us to separate the relative effects of noise exposure on parents, embryos and larvae for offspring growth and mortality. Use of uniquely identifiable transponders, detailed field observations and experimental manipulations of egg predators will enable us to determine how boat noise affects the performance of parents tending eggs and guarding nests, and the consequences for reproductive output.

Focussing on coral reef fish is especially important in the 21st Century as the reefs upon which they depend are among the most globally threatened marine ecosystems, yet they provide habitat for 25% of all fish species, and support fisheries that feed 0.5 billion people and the livelihoods of 100s millions, often in the world's poorest countries. We will test impacts of noise generated by motorboats for two main reasons. First, because coastal regions are experiencing unprecedented human population growth, with a significant rise in coastal recreation and tourism, including boating (e.g. 12.5 million registered powerboats in the USA, 0.5 million boats predicted for the Great Barrier Reef by 2040). Second, because it is feasible to drive boats near to natural and manipulated habitats on coral reefs, we can conduct carefully controlled experiments that are logistically far more challenging with other sources of marine anthropogenic noise (e.g. pile-driving and shipping).

We will work in partnership with marine managers, boat-engine manufacturers, tourism and fishing operators, and conservation agencies to test whether modern four-stroke boat engines have less impact than traditional two-stroke engines, and determine the zone of impact for each engine type. Our research will directly inform future boat-engine design, and provide much-needed evidence for developing management plans for noise on the Great Barrier Reef and in European and US waters.

In addition to a wide range of academic beneficiaries, including coral reef ecologists, animal behaviourists, sensory ecologists, underwater bioacousticians and biologists addressing impacts of anthropogenic noise, our research will benefit a number of stakeholder groups beyond academia:

Industry

Following a workshop on Ecological Impacts of Anthropogenic Noise organised by Simpson and Radford in Bristol in 2012, they have fostered a valuable relationship with the IUCN delegation to the Marine Environment Protection Committee (MEPC) of the International Maritime Organization (UN-led global shipping agency). Simpson will communicate the findings of the proposed research at MEPC committee meetings, building trust with the shipping industry that could lead to the development of experiments that build on our studies of impacts of motorboat noise to assess impacts of ship noise on marine life.

Our work will provide much needed evidence on the ultimate consequences of acoustic disturbance by small vessels, providing valuable impetus for the development of low-noise boat engines. As the project matures, we will seek engagement with international outboard engine manufacturers (e.g. Suzuki, Yamaha, etc.) to develop partnerships where we will use our experimental approaches for Objective 4 to test for reductions in biological impacts of prototype electric and advanced four-stroke engines and modified propeller designs. We will also engage with the ecotourism and recreational fishing industries, as we anticipate emerging evidence of impacts of vessel noise on fish, including assessment of the spatial scale of impact, will encourage marine wildlife viewing operations and fishing companies to change the design of their approach vessels and to develop operational protocols that include acoustic buffer zones.

For the past seven years, Simpson has worked with French ecosystem restoration company Ecocean. Initially developing acoustic attractors for ranching fish and stocking marine protected areas in the Philippines, Simpson (with Radford) has recently completed a £146,000 contract with Ecocean and a global geoscience company (name withheld due to confidentiality agreement). The team built a mobile wetlab in southern France to test the impacts of various sources of anthropogenic noise (shipping, pile-driving and seismic surveys) on Mediterranean fish. Our proposed research will draw on our experience from the French project in aiding development of less impactful noise-generating technologies.

Policy

Following their £600,000 contract with Defra to assess impacts of anthropogenic noise on UK marine fish and invertebrates, as well as two contracts with Marine Scotland to consider impacts of noise on salmon, Simpson and Radford have strong links to the Defra Marine Noise Team, the European Commission Task Group Noise, and offshore renewable energy and marine noise teams at Marine Scotland, Environment Agency, Natural England, Scottish Natural Heritage and Natural Resources Wales. During strategic stakeholder workshops (details in Pathways to Impact), Simpson and Radford will deliver emerging findings from this proposed research, and develop future research and knowledge exchange (KE) programmes (e.g. Innovation Grants, Business Internships, KTPs) that utilise the new experimental approaches to develop policy for species of concern.

The proposed research has obvious relevance to the Australian and Queensland Governments, and to the Great Barrier Reef Marine Park Authority (GBRMPA). Through established links to the Australian Government (Simpson has worked with the governmental Australian Institute of Marine Science for 14 years) and associated contacts at GBRMPA, Simpson will develop a strategic programme of engagement to raise awareness about impacts of noise (not yet integrated in Australian Policy), and to co-develop future research ideas (see Pathways to Impact).