Assessing the social network structure of the Burrunan dolphin in the Gippsland Lakes

Assessing the social network structure of the Burrunan dolphin in the Gippsland Lakes

In contrast to the PPB population, resident Burrunan dolphins in the Gippsland lakes have a unique social system, influenced by an atpyical winter breeding season.

Overview

Social interactions are key to the success and survival of many group-living animals. Social groups actively maintain close proximity due to their being a direct benefit in doing so. Despite benefits such as protection from predators and enhanced foraging efficiency, the stability of social relationships is constantly challenged and altered by the environment, making social networks extremely dynamic and complex. Despite being in relatively close proximity to Port Phillip Bay, these populations are isolated with minimal migration occurring between them, based on genetic structure and diversity (Charlton-Robb et al. 2015). Preliminary social analyses suggests these populations exhibit markedly different social network structures, which could be driven by a number of ecological, social and demographic factors unique to each population. Unlike the PPB population where both males and females remain within their natal range in adulthood, the GL population is maternal-based, meaning the majority of the population are females except during their unique winter breeding season (most Tursiops spp. have summer breeding seasons) when an influx of males entering the lakes from the south-eastern coast of Tasmania in austral winter. There are numerous differences between the population, which provide an exciting opportunity to explore the GL social structure and compare with the PPB population, determining drivers of social cohesion within the population and in doing so, provide an explanation of potential fitness benefits, thus evolutionary adaptations of the populations.

Using robust and established methods to quantify and assess social structure based on photographic fin-identification, we aim to investigate associations among individually identifiable Burrunan dolphins to;

  1. Determine social network structure of Gippsland Lakes population
  2. Investigate changes to social network structure over space and time
  3. Identify the possible drivers of social network structure, thus the evolutionary adaptations of the population

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