Forum member Seiche is official partner for ocean cleanup
Hearing Tests on Wild Whales
Scientists published the first hearing tests on a wild population of healthy marine mammals. The tests on beluga whales in Bristol Bay, AK, revealed that the whales have sensitive hearing abilities and the number of animals that experienced extensive hearing losses was far less than what scientists had anticipated.
The latter findings contrasted with expectations from previous studies of humans and bottlenose dolphins, which showed more hearing loss as they aged, says Aran Mooney, a biologist at Woods Hole Oceanographic Institution (WHOI) and lead author of two new studies on beluga whales. “But unlike the wild beluga population, the dolphins that were studied lived in a very noisy environment, as most humans do.”
At a time when noise in the ocean is increasing from human activities, such as oil and gas exploration and ship traffic, understanding the natural hearing abilities of whales and other endangered marine mammals is crucial to assessing potential noise impacts on animals and to management efforts to mitigate sound-induced hearing loss.
In the two related studies, WHOI researchers and their colleagues measured the hearing sensitivity of 26 wild belugas and then compared the audiograms to acoustic measurements made within their summer habitat in Bristol Bay to study how natural soundscapes—all sounds within their environment—may influence hearing sensitivity. The soundscape also reveals sound clues that the belugas may use to navigate. The first study was published May 8, 2018, in the Journal of Experimental Biology. Results from the soundscape study were published June 20, 2018, in the Journal of Ecoacoustics.
Integrated modelling of Atlantic mackerel distribution patterns and movements: A template for dynamic impact assessments
Modelling is important for impact assessments of anthropogenic pressures on wildlife. Models are particularly useful when dealing with complex dynamic systems (as pelagic ecosystems) where data are limited and if various ‘what if’ scenarios should be tested. The aim of this study was to produce and implement an integrated modelling approach, linking high resolution hydrodynamic models (HDM) of the marine environment with correlative species distribution models (SDM) and agent-based models (ABM), for describing the spatio-temporal distribution and movements of Atlantic mackerel (Scomber scombrus) in the Norwegian Sea. The SDM was fitted with scientific mackerel trawl data as response variables (collected in July and August 2006–2014) and temperature (from the HDM), water depth and time period as predictors of spatial distributions. The SDM was able to produce dynamic predictions of a similar order of magnitude as observed catch per unit effort (CPUE) as well as realistic large-scale distribution patterns, when tested on independent data (not included in the modelling). The ABM was calibrated, with normalized SDM predictions (habitat suitability as a proxy for food availability) and hydrodynamics as input and simulated on a single year (2013) for the period May–October, when the migratory mackerel is present in the study area. A pattern-oriented modelling (POM) approach was used to verify if the model reproduced multiple observed real-world patterns. The ABM produced similar patterns as observed regarding migration timing, growth and large scale geographic distribution. Fine scaled information on mackerel movement and behaviour is limited, which is also reflected in the results. More data and knowledge are therefore required to improve the patterns emerging from fine scaled processes. The potential of the model for assessing an impact of a single seismic survey (mimicking a real survey) was finally evaluated. The exercise allowed estimating the number of affected fish (within 50 km from the sound source) and potential changes in local migrations, with the specific assumed minimum sound pressure thresholds (resulting in a fleeing reaction by the mackerel) set to 165 dB re 1 μPa. The model framework was shown to be useful by allowing simulations of impact scenarios in a realistic and dynamic environment. The model can be further updated when data on fine scale movements of mackerel and most importantly when improved data on response behaviour to impacts of sound become available.
Underwater noise abatement: Economic factors and policy options
Nathan D. Merchant
Underwater noise pollution is becoming globally recognised as a significant threat to aquatic ecosystems and the resources they provide. The effects of noise pollution extend from blue whales to zooplankton, impacting threatened species and affecting key industries including fisheries and ecotourism. In response, policymakers in some jurisdictions have made substantive high-level commitments to address noise pollution, however the implementation of noise reduction measures (noise abatement) remains limited. To support the development of effective noise management policies, this paper explores the economic and policy context to noise abatement in three major noise-generating industries: shipping, offshore windfarm construction, and seismic surveying for oil and gas. In each case, tractable policy options are identified which make considered use of command-and-control and incentive-based measures in light of the available noise abatement methods. Drawing on instructive examples from terrestrial noise management and other sectors, it is concluded that such measures offer the most promising long-term solution to deliver existing and future policy commitments to manage cumulative levels of underwater noise pollution.
Navy efforts to protect whales have limited effect
Naval efforts to protect endangered whales by gradually increasing the noise levels of soner have limited benefit, researchers at the University of St Andrews have found. The process of slowly raising the noise level of sonar, known as 'ramp up' was adopted by several European navies, and geophysical explorers who use airguns to search for oil and gas reserves, as a method to reduce the harmful impact of very loud sounds produced by humans in the sea.
Paul J. Wensveen et al. Lack of behavioural responses of humpback whales (Megaptera novaeangliae) indicate limited effectiveness of sonar mitigation, The Journal of Experimental Biology (2017). DOI: 10.1242/jeb.161232
The International Quiet Ocean Experiment (IQOE)
The IQOE have now launched their re-designed website (www.iqoe.org). The site features all the content as before, with more modern graphics and better integration of the Aquatic Acoustic Library and the database of observing systems.
Lloyd's Register announces new underwater noise notation
Lloyd's Register has released a new underwater noise notation and ShipRight procedure on underwater radiated noise with the intention of helping shipowners minimise underwater noise emmisions when operating in sensitive environments. Increased focus is being placed on underwater noise emissions from vessels and this is creating the need fr a means of controlling underwater noise radiation. New international standards and regulations are anticipated, which will restrict acess to environmentally sensitive areas and limit the types of vessels callign at ports to only those complying with stringent noise level standards.
The importance of particle motion to fishes and invertebrates
Arthur N Popper and Anthony D Hawkins
This paper considers the importance of particle motion to fishes and invertebrates and the steps that need to be taken to improve knowledge of its effects. It is aimed at scientists investigating the impact of sounds on fishes and invertebrates but it is also relevant to regulators, those preparing environmental impact assessments, and to industries creating underwater sound. The overall aim of this paper is to ensure that proper attention is paid to particle motion as a stimulus when evaluating the effects of sound upon aquatic life.
(c) 2018 Acoustical Society of America https://doi.org/10.1121/1.5021594
Marine Scotland is to be involved in the EU-funded Joint Monitoring Programme for Ambient Noise North Sea (JOMOPANS)
The aim of this project is to develop a framework for a fully operational joint monitoring programme for ambient noise in the North Sea. Output will be the tools necessary for managers, planners and other stakeholders to incorporate the effects of ambient noise in theirassessment of the environmental status of the North Sea, and to evaluate measures to improve the environment. Jomopans is in its initial phases and will officially start the 1st of January 2018.
Marine Noise Budgets in Practice
Merchant, N. D., Faulkner, R. F., Martinez, R.