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What role do seagrasses play in the Lake’s
They may not always be aesthetically
pleasing, but seagrasess are a vital component of Lake
I am often asked why seagrasses are so important to
the Lake’s health and this week I will address
this common question.
In areas where seagrasses are lost, marine life is
lost too. Seagrass meadows form the foundations of the
Lake’s food chain and are the nursery grounds
for many of Lake Macquarie’s fish and crustacean
species as they provide food and protection from predators.
A number of epiphytes attach themselves to the leaves
of seagrasses such as small worms called spirorbide
and minute colonial animals known as bryzoans. These
epiphytes are a vital food source for small fish and
other marine life that live in the Lake.
Seagrass meadows also act as a natural filter in the
water. The strap-like leaves of seagrass plants slow
the movement of the water above, allowing any sediment
that is suspended in the water to fall down into the
seagrass meadow where is can be contained. This natural
process helps to protect the Lake’s water quality.
Typically, seagrass beds fringe the shorelines of the
Lake and the roots assist in reducing sand erosion in
When seagrass leaves break off and wash up on the shoreline
it is known as seagrass wrack. It often accumulates
on shorelines to the dismay of some locals. Although
the seagrass wrack may not be visually pleasing to everyone,
an important part of the Lake’s food chain is
destroyed when seagrass wrack is removed from shorelines.
Seagrass wrack is a source of nutrients for marine
life and salt marsh areas and is an essential part the
food chain for the Lake’s ecosystem, whether it
is in or out of the water.
Local Council staff will occasionally remove seagrass
wrack from public reserve areas when it is absolutely
necessary if excessive amounts cover the shoreline.
Removal of seagrass wrack is controlled and regulated
by New South Wales Fisheries.
The Lake is a dynamic and living thing that is constantly
changing. People often comment that some areas of the
Lake previously had sandy bottoms, but are now covered
in seagrass. The size and location of seagrass beds
constantly changes over time and is in fact a positive
sign for the health of the Lake. This change reflects
the evolving nature of the living Lake.
Through working together and protecting the Lake’s
natural processes, the future of Lake Macquarie will