Drivers and annual estimates of marine wildlife entanglement rates

A long-term case study with Australian fur seals

Rebecca R. McIntosh*, Roger Kirkwood, Duncan R. Sutherland, Peter Dann

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Citations (Scopus)


Methods of calculating wildlife entanglement rates are not standardised between studies and often ignore the influence of observer effort, confounding comparisons. From 1997-2013 we identified 359 entangled Australian fur seals at Seal Rocks, south-eastern Australia. Most entanglement materials originated from commercial fisheries; most frequently entangling pups and juveniles. Using Generalized Additive Mixed Models, which incorporated observer effort and survey frequency, we identified that entanglements were observed more frequently amongst pups from July to October as they approached weaning. Neither the decline in regional fishing intensity nor changing seal population size influenced the incidence of entanglements. Using the models, we estimated that 302 (95% CI. =. 182-510) entangled seals were at Seal Rocks each year, equivalent to 1.0% (CI. =. 0.6-1.7%) of the site population. This study highlights the influence of observer effort and the value of long-term datasets for determining the drivers of marine debris entanglements.

Original languageEnglish
Pages (from-to)716-725
Number of pages10
JournalMarine Pollution Bulletin
Issue number2
Publication statusPublished - 30 Dec 2015
Externally publishedYes


  • Arctocephalus pusillus doriferus
  • Fisheries interactions
  • Ghost nets
  • Marine debris
  • Otariid
  • Plastic

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