Assessing disturbance on Australian fur seals

Group of seals ©MMF

Assessing disturbance on Australian fur seals

Overview

The ecology and social dynamics of the Port Phillip Bay fur seals is largely unknown due to a lack of research into the non-breeding aggregation in this region. Much of the research on Australian fur seals to date has focused on the breeding colonies located throughout the Bass Strait, with most breeding occurring at Seal Rocks, Lady Julia Percy Island and The Skerries.

However, these non-breeding aggregations are not given the same protections as breeding colonies, leaving them open to disturbance, particularly in high traffic areas such as PPB. While breeding colonies cannot be approached within 300m (50-100m for permitted vessels depending on season), seals on land can be approached to 30m, and seals on man-made structures, such as the haul-out sites within PPB, can be approached to 5m.

In partnership with Parks Victoria and Zoos Victoria, we will be using camera traps at known haul-out sites throughout Port Phillip Bay to assess levels of environmental and anthropogenic disturbance on fur seals. Elevated levels of disturbance have been shown to have both short- and long-term effects on pinnipeds (seals, sea lions and fur seals) including reduced fitness and changes in foraging strategies. As such, it is important to understand how these animals are responding to disturbance events.

We will also attempt to estimate site usage numbers and aggregation numbers, providing valuable information to Parks Victoria as to the adequacy of current structures or the necessity of future improvements. The impacts of environmental disturbances at these structures may also highlight management ideas for the Bay.

The study will also provide a minimally-invasive method of identifying entanglements and injuries that may otherwise go unreported, allowing for assessment by Zoos Victoria’s Marine Response Unit (MRU).

The project will endeavour to:

  • Assess the levels of environmental and anthropogenic disturbance impacting the fur seals across PPB;
  • Estimate aggregation size, age class, and site usage across PPB;
  • Identify entanglements and injuries MRU assessment.

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