An accurate and adaptable photogrammetric approach for estimating the mass and body condition of pinnipeds using an unmanned aerial system

Details

• Journal Title:
  PLOS ONE
• Personal Author:
  Krause, Douglas J. ; Hinke, Jefferson T. ; Perryman, Wayne L. ; Goebel, Michael E. ; LeRoi, Donald J.
• NOAA Program & Office:
  NMFS (National Marine Fisheries Service) ; SWFSC (Southwest Fisheries Science Center) ; OPR (Office of Protected Resources)
• Description:
  Measurements of body size and mass are fundamental to pinniped population management and research. Manual measurements tend to be accurate but are invasive and logistically challenging to obtain. Ground-based photogrammetric techniques are less invasive, but inherent limitations make them impractical for many field applications. The recent proliferation of unmanned aerial systems (UAS) in wildlife monitoring has provided a promising new platform for the photogrammetry of free-ranging pinnipeds. Leopard seals (Hydrurga leptonyx) are an apex predator in coastal Antarctica whose body condition could be a valuable indicator of ecosystem health. We aerially surveyed leopard seals of known body size and mass to test the precision and accuracy of photogrammetry from a small UAS. Flights were conducted in January and February of 2013 and 2014 and 50 photogrammetric samples were obtained from 15 unrestrained seals. UAS-derived measurements of standard length were accurate to within 2.01 +/- 1.06%, and paired comparisons with ground measurements were statistically indistinguishable. An allometric linear mixed effects model predicted leopard seal mass within 19.40 kg (4.4% error for a 440 kg seal). Photogrammetric measurements from a single, vertical image obtained using UAS provide a noninvasive approach for estimating the mass and body condition of pinnipeds that may be widely applicable.
• Source:
  PLOS ONE
• DOI:
  https://doi.org/10.1371/journal.pone.0187465
• Pubmed Central ID:
  PMC5706667
• Document Type:
  Journal Article
• Place as Subject:
  United States ; Prydz Bay (Antarctica)
• Rights Information:
  CC BY
• Compliance:
  PMC
• Download URL:
  https://repository.library.noaa.gov/view/noaa/24566/noaa_24566_DS1.pdf
• File Type:
  [PDF - 16.54 MB]
• Collection(s):
  National Marine Fisheries Service (NMFS)
• Main Document Checksum:
  urn:sha-512:d687187356a63dec9d0909f89d3b62bef1637ff6cced0b0523e31bfa58851e7406614edf70990097c6ef37acde1387de59a8f7d6be1a63ae39e04f64efe58141