Sunday, January 24, 2010

Sea Anemones at Avalon Beach Tidal Pools


All of the local ocean beaches I've featured on this blog have rock/tidal pools at 
both ends, where the sand gives way to the rocky headland. I took the following 
photos at Avalon beach, which was Beach #3 (see here) in series "Ten Beaches, 
Ten Images".  They are of Australian Waratah Sea Anemone (Actinia tenebrosa), 
which gets its name from the waratah flower:


The following is from Victorian Government's Bayside City Council's website:

Rockpools, Platforms and Reefs

Rockpools, platforms and reefs provide habitat to an amazing diversity of plants and animals. Rock platforms are covered 
twice a day by high tide, thus creating two worlds for many plants and animals living on them.

When the tide is out, large predatory fish are excluded from the rock platform, allowing animals to move around freely and 
exposing plants to open air and sun. The two living worlds created by roockpools provide opportunities not available in the 
open ocean and the sandy shore.

The rocks give many species of barnacles a solid base on which to fix themselves, and the incoming tides wash nutrient-
rich waters over their appendages. Similarly tube worms emerge from their impenetrable limy fortresses as the waves cover 
them and retreat as the waves subside.

Living in rockpools requires specialised adaptations and the Waratah Sea Anemone is an example of a hardy rockpool 
creature.  Looking like a red jelly mass out of water it is able to withstand the heat of the sun for several hours per day, 
survive the beatings of the surf as the tide comes in and take its food and oxygen from water without being able about from 
place to place.

For a long time small marine animals were collected from rockpools for making soups and stews, for use as bait and even 
school field work. The result has been the decimation of populations in the most popular collecting areas. Conserving 
rockpool flora and fauna is now part of all school marine biology programs, reinforced by severe penalties in most states for 
unauthorised collection of animals.

David Hawkes
Untitled, 1997
Oil on board, 15 x 15 cm
Esa Jaske Collection

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