Tag Archives: crustacean

South Australia’s Fleurieu Peninsula underwater

2 Dec

Dear Reader:

 I am snorkelling along the edge of the reef just off Aldinga Beach. The water is shallow and warm with just a light breeze ruffling the surface. Below me the terrain changes from seagrass to sand with a little outcrop of rocky reef in between and I am intent on photographing the variety of marine organisms that inhabit these different habitats.

 

A patch of reef near the seagrass beds

 

The reef has numerous invertebrates clinging to, and encrusting its wide variety of niches and a biscuit star is my first sighting. This pentagonal little seastar can be found on reefs and rocky surfaces and has a number of colour variations between light orange to reddish. It has quite large overlapping plates on its surface and has an arm radius up to 7cms.

 

Biscuit star alongside sea snail on reef

 

Leaving the little patch of reef behind I start to scour the seagrass bed where it meets the sand patches. My choice of location pays dividends as I disturb a blue swimmer crab that has been hunting in the seagrass.

 

Blue swimmer crab does not want to be photographed

 

Blue swimmer crabs have large pincers on their two front legs and paddles on the rear pair. They can be seen moving along the bottom in weedy and sandy areas but often bury themselves in the soft sand and mud. These large crabs can be quite aggressive when approached and feed on live animals as well as scavenging. They are migratory appearing from September to April in SA waters. Taking female Blue Swimmer Crabs with eggs and animals under 11 cms is illegal and there is a personal bag limit of 20 crabs per day. These restrictions help preserve the numbers of this commercially and recreationally valuable species.

These invertebrates are just two of my many encounters on the reef and the bushland around the Fleurieu Peninsula and I shall continue this story in my next post.

Cheers

Baz

Notes:

Over the next few months I will be writing a book about the wildlife of the Fleurieu Peninsula. My posts will reflect the research I am doing and provide more detailed information about each animal that I encounter.

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