SUSTAINABILITY AND THE ENVIRONMENT: LIVING SEAS
The world is our oyster
Overfishing, disease, pollution, poor water quality and dredging have
changed the marine environment within our coastal waters, bringing
some marine species close to extinction. The researchers’ ally in
turning around this perilous situation is Europe’s humble native oyster.
Oysters are no ordinary
molluscs. They’ve been
around for over 500 million
years. They were flourishing
eons before early humans discovered them
as a food source, then as a deity and today
as a seafood delicacy – and they retain a
special place in our folklore and culture.
But it is not the myth of Aphrodite,
the goddess who emerged from the sea
on a (very large) oyster shell, or Giacomo
Casanova’s boundless passions, for which
he credited his oyster diet, that make
oysters special.
Oysters are the ocean’s kidneys
A single oyster filters up to 200 litres of
seawater a day, removing pollutants and
keeping the surrounding water clean
for other sea life to thrive. And oysters
would have been even more productive in
prehistoric times when they were much
larger – up to one metre in diameter.
This filtration role has been crucial to the
health of coastal marine life by providing
clear water that allows sunlight to reach
important habitats such as seagrasses.
Beyond this, oyster reefs create habitats
able to nurture a much higher level of
biodiversity than a flat seabed. This includes
PHOTO: JOANNE PRESTON
Oyster restoration
In addition to repopulating with caged
oysters (see next page), The Solent Oyster
Restoration project has put 20,000 oysters
on the seabed in a large estuary-wide
experiment in the River Hamble ahead of a
large-scale national restoration plan.
Research is also helping to discover
how the commercially and ecologically
devastating disease bonamiosis is spread
is between oysters, and to find out if
there is a genetic basis for resistance
to this disease. "We are also working
to understand other challenges that
the native oyster faces, such as invasive
species like the American slipper limpet
(Crepidula fornicata) and Pacific oyster
(Crassostrea gigas),”
Dr Joanne Preston says. “These are
widespread in the Solent and affecting the
recovery of the native oyster.”
Other research involves mapping
and calculating the value of the services
that marine habitats provide for humans
– known as natural capital valuation.
Habitats such as seagrasses, saltmarshes
and oysters reefs are important in
controlling water quality and carbon
storage, and Dr Preston’s team is
estimating their monetary value.
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ISSUE 1 / 2020