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

Dataset

Description

1. Understanding 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 behavior of echolocating species over a range of scales.

2. We used an extensive passive acoustic dataset 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.

3. At a broad scale, foraging varied seasonally, and was also affected by sea-bed 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.

4. 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.

Data type

Hourly occurrence of bottlenose dolphins' foraging buzzes in POD data from the Moray Firth, Scotland: The data were collected using T-PODs and C-PODs (www.chelonia.co.uk). The foraging buzzes were identified in the echolocation time series using a Gaussian mixture model. For each hourly record, if a buzz was present the value for "pres.buzzes" is equal to 1. For each record, the values of the available covariates are also provided. The column "id.gees" indicates the blocking factor used for GEEs.
Hourly_data.csv

Daily occurrence of bottlenose dolphins' foraging buzzes in POD data from the Moray Firth, Scotland: The data were collected using T-PODs and C-PODs (www.chelonia.co.uk). The foraging buzzes were identified in the echolocation time series using a Gaussian mixture model. For each daily record, if a buzz was present the value for "presdaily.buzzes" is equal to 1. For each record, the values of the available covariates are also provided. The column "id.gees" indicates the blocking factor used for GEEs.
Daily_data.csv

Copyright and Open Data Licencing

This work is licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license.
Date made available18 Jun 2013
PublisherDryad Digital Repository
Geographical coverageScotland, Moray Firth

Keywords

  • Echolocation
  • Feeding buzz
  • Generalized Estimating Equations
  • habitat preference
  • modelling
  • Multi-scale
  • Odontoceta
  • PODs
  • Tursiops
  • Tursiops truncatus

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