Pobblebonk – Animals of the Maribyrnong River Estuary

To explore the microscopic (very small) fauna of the estuary we employed an environmental research company, Ecowise Consultants, to carry out a study of the animals who live in the mud. This layer contains many species that live on the bacteria and algae and other even smaller creatures that live in their thousands, even millions, here and in water bodies fresh and salty. Most of the microinvertebrates here are roughly about the size of a pinhead. All the animals you see here were basically scooped up in a bucket of mud.

The people pictured in this panel are Denise and Katherine from Ecowise Consultants collecting mud to be analysed in the laboratory.

Animals

SULPHUR-CRESTED COCKATOO

Ngaryuk (BW)

SEALS

Seals and dolphins have been found on several occasions over the last few years in the Maribyrnong River Estuary because of improvements in the water quality of the river. This seal was photographed by Warwick Somerville, of Maribyrnong River Cruises a tour boat operator.

WELCOME SWALLOW

There are a number of types of worms that are found in the estuary of the Maribyrnong River.

Some live under rocks and others in the mud and sand on the bottom. One species, Galeolaria caespitosa, makes a white calcareous tube.

CRABS

Crabs can be found all along the muddy edges of the Maribyrnong Estuary feeding mostly on animal and vegetable material. The most common species is the shore crab which grows to about 45 mm.
Wordel (B)

CRUSTACEANS

When we think of crustaceans we think of crabs and crayfish but crustaceans include a wide range of species, many of them part of the microscopic world which is such an important part of the food webs of the river and the wetlands.

BARNACLES

Barnacles are crustaceans that have adapted to a life attached to hard surfaces like rocks and wood. The shell is made up of a number of plates and they feed by sifting the water with feathery feet.

PROTOZOA

Protozoa are small to microscopic single celled animals, usually less than 0.5 mm in length and colourless or translucent, which feed on small particles of decomposing organic matter, bacteria, small algae and other protozoa.

ROTIFERS

Rotifers are also minute animals, comparable in size to Protozoa, but are made up of many cells and possess internal and complicated organs. They are amongst the most abundant of freshwater animals.

COPEPODS

Copepods are the largest group of microcrustacea. They range from marine to freshwater habitats and eat plants & animals. Copepods are a major part of many aquatic animal diets and are the primary link between planktonic algae and animals higher in the food chain.

COROPHIUM

Corophium amphipods, often called mud shrimps, live in U-shaped burrows, preferably in anaerobic sediment of salt marshes and estuaries.

POLYCHAETES

Polychaetes are segmented worms with the ability to regenerate appendages. Polychaetes can be free-moving or sedentary. The sedentary forms construct and live in stabilized burrows or complex tubes. The image taken of this polychaete was taken using an electron microscope by Joan Clark of the Zoology Department at Melbourne University.