Bull Kelp Kristina Hoeppner

Bull Kelp

Durvillaea potatorum

Did You Know?

  • Plants can reach 200 kg in weight
  • Lives up to 14 years and grows 10 – 14 cm a day
  • Found along the coasts of Chile and New Zealand
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A very large brown seaweed (algae). It has dark brown leathery, strap-like branches (thallus).

It attaches to the substrate by a large disc or conical-shaped holdfast. Usually there is a single leathery frond (stalk) from the holdfast, which divides into long segments or fronds.

Its strong holdfast often pulls off pieces of granite during storms which can remain attached to the kelp when washed up on shore.

Size

Up to 8 m long, holdfast up to 25 cm across.

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What to Observe

Search area for 30 minutes and record the following:

  • Abundant: found easily with little searching

  • Frequent: found with minimal searching

  • Rare: only 1 or 2 individuals found with intensive searching

  • Not found: not present during search

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When and Where

When To Look

  • Throughout the year

Where To Look

  • Southern Australia from Robe in South Australia along the Victorian coastline to Bermagui in NSW, including the west, south and east coasts of Tasmania and King Island in Bass Strait
  • Around the low tide mark on exposed coastlines, particularly where there is rough water or considerable wave action
  • Seen at depths of up to 30 m but usually seen clinging to rocks
  • Washed up on beaches after storm events
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What Else?

Similar Species

Durvillaea antarctica, the dominant species in shallow waters around Macquarie Island, may occasionally be found washed ashore in southern parts of Tasmania.