An initiative of Earthwatch Institute

  1. Img_3760_c_gillies-cropped 50-200 cm in length by Chris Gillies
  2. Img_3775__c_gillies-cropped Cray weed washed onshore by Chris Gillies
  3. Phyllospora_hogani__g_edgar Cray weed underwater by Graham Edgar

Phyllospora comosa

Cray Weed


  • Brown seaweed (algae)
  • Central 'strap'
  • Sawtooth-edged leaves (blades)
  • Spindle-shaped floats (bladder) at the end of the short stalks
  • Size: 50-200 cm long, bladders are 2-4 cm long

What to Observe

Search area for 30 minutes and record under the following categories-

  • 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

ClimateWatch Science Advisor

As a result of climate change, warm tropical ocean currents are expected to strengthen and persist for longer periods in southern coastal area normally dominated by cooler waters. The consequent increases in water temperature are likely to result in unfavourable growing conditions for cool water algae species causing seaweed loss in some areas.

When To Look

Throughout the year

Where To Look

  • On exposed coasts with rough water and a hard substrate. It is found from the low tide mark to around 20 m water depth, and also in deep rock pools.
  • The south-east Australian coast, from Robe in South Australia, around Victoria and Tasmania, to Port Macquarie in New South Wales. It is also found at Norfolk Island.


Edgar GJ 1997. Australian Marine Life: the plants and animals of temperate waters. Reed Books, Kew.

Quinn GP, Wescott GC & Synnot RN 1992. Life on the Rocky Shores of South-Eastern Australia: an illustrated field guide. Victorian National Parks Association, Melbourne.

Womersley HBS 1967. A critical survey of the marine algae of southern Australia. II. Phaeophyta. Australian Journal of Botany 15, 189–270.

Womersley HBS 1987. The marine benthic flora of southern Australia. Part II. pp. 481, 169 figs, 1 table, 8 plates, 4 maps. Adelaide: South Australian Government Printing Division.


  1. Search Species

  1. What Else?

    Bristled crayweed (Seirococcus axillaris). Cray weed (P. comosa) can easily be distinguished from bristled crayweed by its saw toothed edged blades and by fishbone looking shape.

  1. Did You Know?

    Its scientific name is Latin for tufts of leaves or hairs.

    Baby crayfish often shelter in it.

    The bladders keep its fronds upright in the water so that they are more exposed to the sunlight.