Using unmanned aerial vehicle (UAV) surveys and image analysis in the study of large surface-associated marine species: a case study on reef sharks Carcharhinus melanopterus shoaling behaviour Articles uri icon

authors

  • RIEUCAU, GUILLAUME
  • KISZKA, JEREMY J.
  • CASTILLO MONTOYA, JOSE CARLOS
  • MOURIER, JOHANN
  • BOSWELL, KEVIN M.
  • HEITHAUS, MICHAEL R.

publication date

  • June 2018

start page

  • 119

end page

  • 127

issue

  • 1

volume

  • 93

International Standard Serial Number (ISSN)

  • 0022-1112

abstract

  • A novel image analysis-based technique applied to unmanned aerial vehicle (UAV) survey data is described to detect and locate individual free-ranging sharks within aggregations. The method allows rapid collection of data and quantification of fine-scale swimming and collective patterns of sharks. We demonstrate the usefulness of this technique in a small-scale case study exploring the shoaling tendencies of blacktip reef sharks Carcharhinus melanopterus in a large lagoon within Moorea, French Polynesia. Using our approach, we found that C. melanopterus displayed increased alignment with shoal companions when distributed over a sandflat where they are regularly fed for ecotourism purposes as compared with when they shoaled in a deeper adjacent channel. Our case study highlights the potential of a relatively low-cost method that combines UAV survey data and image analysis to detect differences in shoaling patterns of free-ranging sharks in shallow habitats. This approach offers an alternative to current techniques commonly used in controlled settings that require time-consuming post-processing effort.

keywords

  • blacktip reef shark; carcharhinus melanopterus; image analysis; shoaling behaviour; uav