A killer whale social network is vulnerable to targeted removals

Rob Williams, David Lusseau

Research output: Contribution to journalArticle

102 Citations (Scopus)

Abstract

Individuals play various roles in maintaining social integrity of mammalian populations. However, many models developed for managing wildlife resources assume that all individuals are equal. Killer whales are social animals that rely on relationships within and among family groups for survival. In the northeastern Pacific, fish-eating, 'resident' killer whale populations are composed of matrilines from which offspring do not disperse. We analysed the influence of various individuals' age, sex and matrilineal affiliation on their position in a social network. Here, we show that some matrilines appeared to play more central roles than others in the network. Furthermore, juvenile whales, especially females, appeared to play a central role in maintaining network cohesion. These two key findings were supported subsequently by simulating removal of different individuals. The network was robust to random removals; however, simulations that mimicked historic live-captures from the northeastern Pacific were likely to break the network graph into isolated groups. This finding raises concern regarding targeted takes, such as live-capture or drive fisheries, of matrilineal cetaceans.

Original languageEnglish
Pages (from-to)497-500
Number of pages4
JournalBiology Letters
Volume2
DOIs
Publication statusPublished - 2006

Keywords

  • social network
  • anthropogenic impact
  • sociality
  • live capture
  • by-catch
  • matriline
  • BRITISH-COLUMBIA
  • ORCINUS-ORCA

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