(water splashing)
- Sydney's waters are only years
away from becoming tropical.
Yep, The Great Barrier
Reef is moving to Sydney.
But don't get excited,
it's not such a good thing.
Well our tropical corrals
have started to show up,
Several others not that much corral to see
but other impacts could be enormous.
So what's going on?
If you watched Finding
Nemo you might remember
Nemo's dad Marlin and
a blue tang fish, Dory
they travel to Sydney on a turtle and
their on a current called the EAC.
The East Australian Current.
Well that's kind of right, the EAC does
start near here out from Sydney.
And it brings warn northern waters down
along the eastern coastline.
The EAC waters are warming and twice as
fast as any other area.
Sydney's waters are
temperate, not tropical.
Here underwater kelp
forests should dominate our
Rocky Four Shores.
And kelp forests are
nutrient rich environments.
They provide food and shelter for hundreds
of different species.
They support the fishery worth
more than 10 billion dollars a year.
But temperate reefs need
relatively cool water
so this warmer water it stresses the kelp
and when stressed it's
more prime to disease.
And also to weakening of the structures
that support them to the reef.
The warmer tropical waters
carry less nutrients
so the animals that live in the
kelp forests are also effected.
Not only is the kelp
impacted by the warm waters,
but the animals that live
in the kelp forest to.
The whole ecosystem is impacted.
Recently West Australian kelp forests
were wiped out by an
extreme breed eat wave
that lasted only a couple of weeks.
This isn't just happening here.
It's happening in other
temperate regions as well.
Kelp forests are declining worldwide.
38 percent of the worlds kelp forests
have gone largely due to warming oceans.
But it's not all due to heat stress.
Other factors often to do with
our behavior are also playing a part.
Kelp forests in South Australia
have disappeared because of the nutrient
rich polluted waste waters.
While in Eastern Tasmania 95 percent
of kelp forests are gone.
This is because kelp eating sea urchins
are out of control.
Sea urchins graze on the kelp forest
faster than it can reproduce.
Lobsters usually eat the urchins and
keep their numbers under control.
But overfishing of the
lobsters has upset the balance.
But species can move so all is not lost.
Our kelp may be able to move further south
but not those in Tasmania.
They'll eventually be driven off
the edge of the Australian continent.
Beyond that, there's nowhere to go.
Climate change increases
the magnitude and rate
of species movement globally.
Some species will adapt better than others
to those rapidly changing conditions.
Tropical fish like Nemo and Dory
have started to appear here
in New South Wales already.
But this can cause other problems.
Species that have never
coexisted, now have to.
Those lovely tropical
fish, surgeonfish like Dory
that have just turned up off of Sydney,
they graze really heavily.
This increase in grazing
has a further impact
on our already stressed kelp forest.
Dory, go home.
Does it matter that
temperate areas like the
waters here of Sydney
are becoming tropical?
Well yeah.
Our temperate areas are
extremely biologically
rich and support important fisheries.
Tropicalization of our
temperate marine kelp forests
will have serious economic consequences.
For wealthier countries,
these challenges may be
less devastating than for others.
And hey in some areas
the movement of marine
species will create a
better economic situation.
This is happening right
now in Northern India.
Where sardines have shifted northwards an
enormous wind for the Indian
Coast or fishing communities.
For us closer to home Skipjack Tuna
may be less abundant
in the Western Pacific.
Many countries in our
region depend on this
fishery for food security
and economic development.
So there will be winners
and losers in this
marine species reshuffle.
Although we don't know the
outcomes of tropicalization
on our temperate reef
systems, we soon will.
And it's happening right now.
(water splashing)
