© 2020 The Abyss Project. All rights
reserved.
Sydney waterways have
serious biodiversity loss along with a delayed and
inconsistent ecosystem recovery following the mass
devastation caused by the series of record-breaking natural
disasters (drought, bushfires, floods) according to
researchers at the Abyss Project, a marine research team
based in Sydney. The research team has joined forces with
sovereign elders of The Gweagal/Bidjigal Tribal Elders
Council, the traditional custodians of Botany Bay to share
knowledge to complete the historical picture of the waters
they study. The La Perouse (Guriwal) Aboriginal community
are the longest functioning and only discreet community in
Sydney with unbroken ancestral ties to country.
Aunty
Yvonne Simms (Bidjigal Sovereign Elder) expressed her
concerns, saying “We can’t eat anything from the bay
anymore and we fear this event is much greater than just
seasonal storm damage. With the amount of industry
surrounding the bay, chemical pollutants and dredging, there
are already many animals gone and this extreme event may
just be the tipping point for others.”
“We are
concerned by the way our waterways are recovering. Following
the near-complete loss of life in many areas, some study
sites are yet to start regenerating 4 months later. In
contrast, other areas have early pioneering species
completely dominating the landscape with some invasive
species appearing to outcompete indigenous species which is
greatly altering community structures. We just don’t know
what the new normal will look like in the future.”, said
Carl Fallon, Founder and scientific diver at the Abyss
Project.
In March 2020 just before the COVID lockdown
was announced, the group discovered a ‘Mass Mortality
Event’ within Sydney waterways that devastated marine life
within inshore shallow areas 0-8 metres following the worst
storms in 20 years. The group have been studying and
collecting observational and photographic records of change
in the waters from the Hawkesbury to Port Hacking Rivers for
over 10 years. The group continued to investigate the area
throughout the COVID lockdown and have been recording their
findings. They now call for further investigation with
shared studies from other research groups in other, effected
coastal areas throughout NSW.
Most severely impacted
were shallow-water habitats with no adjacent deep-water
locations that could help flush and dilute the deadly
runoff. The lockdown stopped the release of the independent
report and the groups observations have not been included in
the Royal Commission into the
bushfires.
Carl Fallon, Co-Founding
Director and Scientific Diver at The Abyss Project, said,
“The whole ocean’s chemistry changed for that window of
time, creating mayhem underwater which kicked off a mass
mortality event. We will only know the full impacts in the
coming years that the bushfires had on the marine
environment through continuous scientific research. Any
species relying on these shallow regions for milestones in
their lifecycle, such as breeding or recruitment, will have
been affected in some capacity. Right now, no one knows the
extent of the impact. We will need to continue monitoring
the ecosystem’s recovery.”
Carl Fallon
said, “The ocean was black with ash and suspended debris,
combined with flood waters which changed the ocean chemistry
creating mayhem underwater that kicked off the mass
mortality event. We will only know the full impacts in the
coming years that the bushfires had on the marine
environment through continuous scientific
research.
Nathalie Simmonds Director and Head of
Marine Science at the Abyss Project who prepared the report
said “The unique and unprecedented sequence and scale of
the 3 natural disasters have resulted in ecosystem collapse
mirroring terrestrial images of the devastated firegrounds.
Shallow inshore coastal waters have been transformed. Our
initial observations following the mortality event have
shown; these events have caused a serious imbalance in the
ecosystem with inconsistent rates of regeneration between
sites. Our major concerns are the observations of some
individual species completely dominating entire habitats
while other species are failing to recruit where they
previously flourished. Opportunistic species which more
often than not are introduced, or invasive are exhibiting
monodominance, outcompeting slower growing native species.
This prevents the capability for various soft body ecosystem
engineering species such as tunicates, sponges and corals
from returning or thriving in a previously biodiverse and
balanced ecosystem.”
Several points have contributed
to the extent of devastation found in the waterways. They
include:
- The two-year drought that proceeded the
bushfires contributed to the hardened ground so that the
initial rain ran off the ground, carrying ash to Sydney
waterways. - The storms immediately following the
bushfires were the worst reported in 20 years. This
culminated in extremely hard ground with a sudden influx of
heavy rain. Ash from the unprecedented fires was washed away
by the stormwater and deposited into the surrounding
waterways.
David Booth, Fish Ecology Expert from
UTS. “Whilst there wasn’t devastation to the fish in the
areas the Abyss Project studied, we know there were
significant numbers who died closer to the water entry
points where ash concentration was highest.”
Gary
Hamer, renowned retired NSW Fisheries Researcher has
contributed scientific evidence of the Mass Mortality Event
to the Abyss Projects Report. This evidence shows inshore
shellfish species (Conch’s – Turban Snails) that were
devastated with reports of close to 90% mortalities
recorded, are now missing recruitment milestones which
points to a collapsed community.
Conch’s are a
culturally significant species to the Bidjigal People and
have been collected from the foreshore of Botany Bay for
millennia.
