Effects of noise and by-catch on a Danish harbour porpoise population

Summary Changes in natural patterns of animal behaviour and physiology resulting from anthropogenic disturbance may alter the conservation status of a population if they affect the ability of individuals to survive, breed or grow. However, information to forecast population‐level consequences of such changes is often lacking. We developed an interim framework to assess the population consequences of disturbance when empirical information is sparse. We show how daily effects of disturbance, which are often straightforward to estimate, can be scaled to the disturbance duration and to multiple sources of disturbance. We used expert elicitation to estimate parameters that define how changes in individual behaviour or physiology affect vital rates and incorporated them into a stochastic population model. Model outputs can be used to evaluate cumulative impacts of disturbance over space and time. As an example, we forecast the potential effects of disturbance from offshore wind farm construction on the North Sea harbour porpoise (Phocoena phocoena) population. Synthesis and applications. The interim framework can be used to forecast the effects of disturbances from human activities on animal populations, to assess the effectiveness of mitigation measures and to identify priority areas for research that reduces uncertainty in population forecasts. The last two applications are likely to be important in situations where there is a risk of unacceptable change in a species' conservation status. The framework should, however, be augmented with empirical data as soon as these are available.

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“…; Nabe‐Nielsen et al . ) have developed similar approaches, but these are location and/or species specific.…”

Section: Discussionmentioning

confidence: 99%

An interim framework for assessing the population consequences of disturbance

King

Schick

Donovan³

et al. 2015

Methods Ecol Evol

121

119

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“…Nevertheless, the observed response of the 4 species, coupled with what we know about their ecology and their spatial and temporal distribution in broader Irish waters, suggest that there were no long-term population effects as a result of construction-related activity or vessel traffic. However, a lack of empirical data often makes it difficult to quantify population consequences of disturbance, as a detailed knowledge of the spatial and temporal use of the area by the target species as well as a comprehensive understanding of the location, timing and potential impacts associated with disturbances, are required (Thompson et al 2013b, Nabe-Nielsen et al 2014, King et al 2015. Even if these data are available, expert judgement is still often required to link disturbances to proxies for individual fitness, which then feed into population models (Thompson et al 2013b, King et al 2015.…”

Section: Discussionmentioning

confidence: 99%

Effect of construction-related activities and vessel traffic on marine mammals

Culloch¹,

Anderwald²,

Brandecker³

et al. 2016

Mar. Ecol. Prog. Ser.

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During the construction of a gas pipeline from an offshore gas field in northwest Ireland, a year-round shore-based marine mammal monitoring programme was undertaken. Using 6 yr of data, generalised estimating equations-generalised additive models (GEE-GAMs) were used to investigate if construction-related activity and vessel traffic influenced the occurrence of common dolphin, minke whale, harbour porpoise and grey seal within the area where the pipeline made landfall. Construction-related activity reduced harbour porpoise and minke whale presence, whilst an increase in vessel numbers (independent of construction-related activity) reduced common dolphin presence. All species showed some degree of annual and seasonal variation in occurrence. For common dolphins and harbour porpoises, we found similar seasonal patterns to those reported in broader Irish waters, which tentatively suggests that seasonal patterns persisted irrespective of construction-related activity or vessel traffic, indicating that any impact might have been only short-term. Multiple construction-related activities occurred simultaneously in different areas, and the inter-annual variation may, in part, be an indication of variation in species' response to particular activities, their intensity and their location. However, the precise location of the activities was not regularly recorded, limiting our ability to investigate the fine-scale spatio−temporal impact of the diverse range of construction-related activities. Improved communication and coordination between developers, regulators and scientists will help ensure that monitoring programmes are effective and efficient, to better inform our understanding of potential impacts and to mitigate effectively against them for future developments.

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“…Porpoise occurrence and activity is typically characterized by large seasonal and diel variability [19,31,32], as also reflected in our results (figure 2). Further studies are now required to explore the environmental conditions that drive this variation, and develop energetic models to assess whether this scale of disturbance has long-term consequences for individual energy budgets [33].…”

Section: Discussionmentioning

confidence: 99%

Variation in harbour porpoise activity in response to seismic survey noise

et al. 2014

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Animals exposed to anthropogenic disturbance make trade-offs between perceived risk and the cost of leaving disturbed areas. Impact assessments tend to focus on overt behavioural responses leading to displacement, but tradeoffs may also impact individual energy budgets through reduced foraging performance. Previous studies found no evidence for broad-scale displacement of harbour porpoises exposed to impulse noise from a 10 day two-dimensional seismic survey. Here, we used an array of passive acoustic loggers coupled with calibrated noise measurements to test whether the seismic survey influenced the activity patterns of porpoises remaining in the area. We showed that the probability of recording a buzz declined by 15% in the ensonified area and was positively related to distance from the source vessel. We also estimated received levels at the hydrophones and characterized the noise response curve. Our results demonstrate how environmental impact assessments can be developed to assess more subtle effects of noise disturbance on activity patterns and foraging efficiency.

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Effects of noise and by-catch on a Danish harbour porpoise population

Cited by 77 publications

References 48 publications

An interim framework for assessing the population consequences of disturbance

An interim framework for assessing the population consequences of disturbance

Effect of construction-related activities and vessel traffic on marine mammals

Variation in harbour porpoise activity in response to seismic survey noise

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