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The Vessels and Burrunan dolphin project is one of eight projects that has been funded to help protect the wildlife of the Gippsland Lakes.

With only 63 resident endangered Burrunan dolphins living in the Gippsland Lakes, there is a need to manage the impact that humans have on the dolphins.

In order to do that, we need to understand what those effects are, and how often and under what circumstances, interactions between the dolphins and humans occur.

Dolphins shifting habitat

In summer there is a significant drop in sightings of the Burrunan dolphins from Lake King to Lakes Entrance, compared to winter – 16% to 92%. This could be the result of increased human activities in the area in warmer months, especially increased boat traffic between Lakes Entrance and Metung.

In 2014, the area had twice as many visitors in the summer months, December to March (50,268), as it did in the winter months, July to October (23,297).

Other potential drivers for shift in habitat include:

  • Fluctuations in ocean currents and fronts.
  • Predator pressure.
  • Prey availability and the effects of anthropogenic (human induced) sources, such as boat traffic.

The project

This project will look into potential reasons for seasonal distribution of the Gippsland Lakes’ resident Burrunan dolphins and determine if their observed movements are driven by human or environmental factors.

The primary objective of this project, delivered by the Marine Mammal Foundation (MMF), is to:

  • Work out the frequency and level of marine vessel interactions with dolphins.
  • Assess boat and jet ski compliance with the regulations and approach distances as set out in the Wildlife (Marine Mammal) Regulations 2009.
  • Assess what impact the interactions between dolphins and boats and jet skis and noise is having. The project will be looking specifically at dolphin behaviour and core biological activities such as feeding, resting, mating and social, and therefore on the condition of the dolphins.

The project will also investigate potential environmental drivers behind the Burrunan dolphin’s seasonal shift in habitat use in the Gippsland Lakes, exploring factors such as prey availability and preferred habitat.

The MMF will incorporate the Combined Biotope Classification Scheme (CBiCS), for classifying all marine habitats. Once classified, environmental/habitat characteristics can be correlated with high dolphin usage areas to explore possible environmental drivers in greater detail.

Research=better understanding

To properly manage the effects of human activities on the small and isolated Gippsland Lakes dolphin population, the rate at which the animals encounter potential stressors must be measured.

Currently there is no research on the actual impact of boats and jet skis on the Burrunan dolphin’s behaviour or core activity. It is crucial to investigate the number of interactions between boats/jet skis and dolphins to assess the actual impact they are having on the vulnerable Burrunan dolphin population.

  • Vessel impact has been hypothesised as a main driver for the Burrunan dolphins shift in seasonal movement patterns, and could create displacement, causing sensitive dolphins to move from high impact areas to low impact areas, affecting behaviour and condition.
  • As dolphins rely heavily on sound production to navigate, communicate, find prey and in social behaviour. Boating noise can disrupt those core biological activities, affect prey, mask acoustics cues and may cause dolphins to adjust call rates and shift their whistle frequencies.
  • This shift in distribution could also relate to seasonal fish distribution, and it is important to determine if areas with fish nursery grounds, seagrass habitat or sandy substrate are important to the dolphin’s distribution.

Habitat mapping carried out as part of this project will classify and document different habitats across the Lakes and determine which areas are significant for the dolphins and require greater protection.

What you can do

  • A team of dedicated citizen scientists will be enlisted to assist with land-based observations.
  • There will be opportunities throughout the year to assist MMF research observations from key vantage locations.

These opportunities will offer a unique opportunity for community members to collect information on the dolphins, while not adding to the number of vessels on the water. MMF will also encourage sightings to be reported throughout the year (whenever sighted), to help with their knowledge and understanding of Burrunan dolphin movement patterns.

 

This project is funded by the Victorian State Government for the Gippsland Lakes.

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