What it looks like: This largest of marine mammals can grow to 30 m long. It is a mottled blue-grey, and has a very small fin towards the end of its back. It filters food from the water through numerous long grooves on its throat. Difficult to see, Blue Whales spend most of their time below the surface of the water.

Blue Whale - Balaenoptera musculus

Photo: © Patty Geary & ACS


Where it lives: Blue Whales live in all major oceans, annually migrating from tropical breeding grounds to summer feeding grounds. Blue Whales breed every 2-3 years, having one calf at a time. They feed in areas of coldwater upwellings, and spend summer in the Southern Ocean, feeding on krill and squid. Most sighting are of solitary animals or of a female with her calf. The only Northern Territory records are of Blue Whales washed up on beaches.

Importance as an indicator: Blue Whale records in Northern Territory waters are a testament to the resilience of a species once hunted to near-extinction, but now recovering. Threats remain from ship collisions, entanglement in nets, noise from offshore construction and excessive tourist attention. Depletion of krill stocks from over-fishing or climate change are significant concern. Pressure to resume commercial whaling is mounting.

Look after Blue Whale by minimising your contribution to climate change. If whale-watching, do not interfere with or distress the animals. Avoid activities that contribute to marine pollution, including noise pollution. Commercial fisheries should use nets that do not ensnare whales. Southern fisheries should be managed to prevent overfishing of krill.

Best Practice Management for Blue Whale

* Manage fisheries sustainably * Adapt longline equipment to reduce seabird bycatch * Reduce bycatch * Prevent marine pollution * Minimise tourist impact * Minimise your contribution to climate change * More information is needed about this species

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