Scale-dependent foraging ecology of a marine top predator modelled using passive acoustic data

Enrico Pirotta*, Paul M. Thompson, Peter I. Miller, Kate L. Brookes, Barbara Cheney, Tim R. Barton, Isla M. Graham, David Lusseau

*Corresponding author for this work

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

1Understanding which environmental factors drive foraging preferences is critical for the development of effective management measures, but resource use patterns may emerge from processes that occur at different spatial and temporal scales. Direct observations of foraging are also especially challenging in marine predators, but passive acoustic techniques provide opportunities to study the behaviour of echolocating species over a range of scales. We used an extensive passive acoustic data set to investigate the distribution and temporal dynamics of foraging in bottlenose dolphins using the Moray Firth (Scotland, UK). Echolocation buzzes were identified with a mixture model of detected echolocation inter-click intervals and used as a proxy of foraging activity. A robust modelling approach accounting for autocorrelation in the data was then used to evaluate which environmental factors were associated with the observed dynamics at two different spatial and temporal scales. At a broad scale, foraging varied seasonally and was also affected by seabed slope and shelf-sea fronts. At a finer scale, we identified variation in seasonal use and local interactions with tidal processes. Foraging was best predicted at a daily scale, accounting for site specificity in the shape of the estimated relationships. This study demonstrates how passive acoustic data can be used to understand foraging ecology in echolocating species and provides a robust analytical procedure for describing spatio-temporal patterns. Associations between foraging and environmental characteristics varied according to spatial and temporal scale, highlighting the need for a multi-scale approach. Our results indicate that dolphins respond to coarser scale temporal dynamics, but have a detailed understanding of finer-scale spatial distribution of resources.

Original languageEnglish
Pages (from-to)206-217
Number of pages12
JournalFunctional Ecology
Volume28
Issue number1
Early online date31 Jul 2013
DOIs
Publication statusPublished - Feb 2014

Keywords

  • echolocation
  • feeding buzz
  • GEEs
  • habitat preference
  • modelling
  • multi-scale
  • PODs
  • Tursiops
  • bottle-nosed dolphins
  • generalized estimating equations
  • habitat selection
  • echolocation behavior
  • tursiops-truncatus
  • harbor porpoises
  • elephant seals
  • T-pods
  • prey
  • hotspots

Cite this

Scale-dependent foraging ecology of a marine top predator modelled using passive acoustic data. / Pirotta, Enrico; Thompson, Paul M.; Miller, Peter I.; Brookes, Kate L.; Cheney, Barbara; Barton, Tim R.; Graham, Isla M.; Lusseau, David.

In: Functional Ecology, Vol. 28, No. 1, 02.2014, p. 206-217.

Research output: Contribution to journalArticle

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abstract = "1Understanding which environmental factors drive foraging preferences is critical for the development of effective management measures, but resource use patterns may emerge from processes that occur at different spatial and temporal scales. Direct observations of foraging are also especially challenging in marine predators, but passive acoustic techniques provide opportunities to study the behaviour of echolocating species over a range of scales. We used an extensive passive acoustic data set to investigate the distribution and temporal dynamics of foraging in bottlenose dolphins using the Moray Firth (Scotland, UK). Echolocation buzzes were identified with a mixture model of detected echolocation inter-click intervals and used as a proxy of foraging activity. A robust modelling approach accounting for autocorrelation in the data was then used to evaluate which environmental factors were associated with the observed dynamics at two different spatial and temporal scales. At a broad scale, foraging varied seasonally and was also affected by seabed slope and shelf-sea fronts. At a finer scale, we identified variation in seasonal use and local interactions with tidal processes. Foraging was best predicted at a daily scale, accounting for site specificity in the shape of the estimated relationships. This study demonstrates how passive acoustic data can be used to understand foraging ecology in echolocating species and provides a robust analytical procedure for describing spatio-temporal patterns. Associations between foraging and environmental characteristics varied according to spatial and temporal scale, highlighting the need for a multi-scale approach. Our results indicate that dolphins respond to coarser scale temporal dynamics, but have a detailed understanding of finer-scale spatial distribution of resources.",
keywords = "echolocation, feeding buzz, GEEs, habitat preference, modelling, multi-scale, PODs, Tursiops, bottle-nosed dolphins, generalized estimating equations, habitat selection, echolocation behavior, tursiops-truncatus, harbor porpoises, elephant seals, T-pods, prey, hotspots",
author = "Enrico Pirotta and Thompson, {Paul M.} and Miller, {Peter I.} and Brookes, {Kate L.} and Barbara Cheney and Barton, {Tim R.} and Graham, {Isla M.} and David Lusseau",
note = "This work received funding from the MASTS pooling initiative (the Marine Alliance for Science and Technology for Scotland), and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. Passive acoustic data were collected during a series of grants and contracts from Scottish Natural Heritage, Scottish Government, the European Union, Department of Energy & Climate Change, COWRIE, Oil & Gas UK and Talisman Energy (UK) Ltd. Satellite data were received and processed by the NERC Earth Observation Data Acquisition and Analysis Service (NEODAAS) at Dundee University and Plymouth Marine Laboratory (www.neodaas.ac.uk). POLPRED model for tidal information was kindly provided by NERC National Oceanography Centre (Liverpool, UK). The authors would also like to thank Dr. Helen Bailey and Ana Candido for their contribution to the collection of some of the data used in the present study. Thanks to Dr. Nick Tregenza for his advice on POD data processing, Dr. Beth Scott for suggesting the use of the tidal mixing parameter, Dr. Steve Palmer for his GIS help and Dr. Marianne Marcoux for invaluable discussions during the early phases of this work. Finally, we thank two anonymous reviewers for their helpful comments.",
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AU - Barton, Tim R.

AU - Graham, Isla M.

AU - Lusseau, David

N1 - This work received funding from the MASTS pooling initiative (the Marine Alliance for Science and Technology for Scotland), and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. Passive acoustic data were collected during a series of grants and contracts from Scottish Natural Heritage, Scottish Government, the European Union, Department of Energy & Climate Change, COWRIE, Oil & Gas UK and Talisman Energy (UK) Ltd. Satellite data were received and processed by the NERC Earth Observation Data Acquisition and Analysis Service (NEODAAS) at Dundee University and Plymouth Marine Laboratory (www.neodaas.ac.uk). POLPRED model for tidal information was kindly provided by NERC National Oceanography Centre (Liverpool, UK). The authors would also like to thank Dr. Helen Bailey and Ana Candido for their contribution to the collection of some of the data used in the present study. Thanks to Dr. Nick Tregenza for his advice on POD data processing, Dr. Beth Scott for suggesting the use of the tidal mixing parameter, Dr. Steve Palmer for his GIS help and Dr. Marianne Marcoux for invaluable discussions during the early phases of this work. Finally, we thank two anonymous reviewers for their helpful comments.

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N2 - 1Understanding which environmental factors drive foraging preferences is critical for the development of effective management measures, but resource use patterns may emerge from processes that occur at different spatial and temporal scales. Direct observations of foraging are also especially challenging in marine predators, but passive acoustic techniques provide opportunities to study the behaviour of echolocating species over a range of scales. We used an extensive passive acoustic data set to investigate the distribution and temporal dynamics of foraging in bottlenose dolphins using the Moray Firth (Scotland, UK). Echolocation buzzes were identified with a mixture model of detected echolocation inter-click intervals and used as a proxy of foraging activity. A robust modelling approach accounting for autocorrelation in the data was then used to evaluate which environmental factors were associated with the observed dynamics at two different spatial and temporal scales. At a broad scale, foraging varied seasonally and was also affected by seabed slope and shelf-sea fronts. At a finer scale, we identified variation in seasonal use and local interactions with tidal processes. Foraging was best predicted at a daily scale, accounting for site specificity in the shape of the estimated relationships. This study demonstrates how passive acoustic data can be used to understand foraging ecology in echolocating species and provides a robust analytical procedure for describing spatio-temporal patterns. Associations between foraging and environmental characteristics varied according to spatial and temporal scale, highlighting the need for a multi-scale approach. Our results indicate that dolphins respond to coarser scale temporal dynamics, but have a detailed understanding of finer-scale spatial distribution of resources.

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KW - echolocation

KW - feeding buzz

KW - GEEs

KW - habitat preference

KW - modelling

KW - multi-scale

KW - PODs

KW - Tursiops

KW - bottle-nosed dolphins

KW - generalized estimating equations

KW - habitat selection

KW - echolocation behavior

KW - tursiops-truncatus

KW - harbor porpoises

KW - elephant seals

KW - T-pods

KW - prey

KW - hotspots

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JO - Functional Ecology

JF - Functional Ecology

SN - 0269-8463

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