Importance of Natural Resources

Ask an Expert: Why Are Oysters Important for the Chesapeake Bay

Hi everyone, my name is Allison
Colden and I’m the Maryland Fisheries Scientist for the Chesapeake
Bay Foundation. I’m out here this afternoon on Blackwalnut
Creek. You can see this beautiful creek right next to our
office here in Annapolis, Maryland. And I’m out here today
and you may see this pole behind me, on one of our restoration
oyster reefs. We built this reef here in Blackwalnut Creek
to help restore oysters in this area and all of the benefits that
they provide. So while you all are stuck at home in this era
of physical distancing, we can still connect with nature. So
that’s what we’re doing here today and today I wanna get up close
and personal with the Eastern oyster. You can see here,
I have some oysters that we grew here at the Philip Merrill
Center and I wanted to spend some time today telling you five
things that you may not know about the Eastern oyster. So first
of all the Eastern oyster is the species of oyster we have here
in the Chesapeake Bay, but it’s not just native to our region.
In fact, the Eastern oyster is native to the entirety of the
East Coast of North America. all the way from Canada down
to Mexico and it’s also found in the Gulf of Mexico. So these
are pretty wide-ranging oysters and are found all along the East
Coast. Second, the oyster is what’s considered a bivalve mollusk.
So let’s take a moment to break that down a little bit. Bi
meaning two and valve meaning shells–so it can kinda be hard to
see here because these are smaller oysters that are still connected
to a larger shell, but each oyster has two shells and this
is what one of the shells looks like. So this is the left
side valve and when this oyster was living there would have been
another shell right there connected on the side and those
two shells are connected by a very strong ligament at the bottom
and the bottom of an oyster is known as the umbo. So if you’ve
ever tried to shuck an oyster to eat, you know how difficult
it can be to break that ligament at the bottom of the shell
of the umbo to get it open and the reason for that is as you
know, oysters have very soft bodies. So these shells are putting
together or held together by that ligament so that they can
protect the soft body of the oyster that’s inside. A second interesting
fact about the Eastern oyster is that this species
of oyster forms oyster reefs. So that is very important
and the way that they form oyster reefs, you can sort of see here,
is oyster larvae that float around in the water column are looking
for a place to settle and they’re looking for a place
to settle and live for the rest of their life and they seek out
and settle on other oyster shells and other living oysters
and the reason that they do that is over generation after generation,
they form these large structures that we know as oyster
reefs. not only are these oyster reefs important because they
provide the habitat for oysters after generation after generation
themselves, but they also provide habitat for hundreds
of other species of the Chesapeake Bay. These are fish, crabs,
worms, other critters that live on and around an oyster reef.
Basically what these oysters do in constructing this habitat is
build a condo for hundreds of other species to come live in. So
that’s super important to the Chesapeake Bay because without these
oyster reefs, those other species that rely on oyster reefs
just are not as productive as they could be. Fourth, these are
very important water filtration powerhouses. So oysters are what’s
called a filter feeder and the reason they’re called that is
because they take water into their bodies and they filter out
of that water, algae and other particles that are nutritious for
them to eat and when they’re doing that sometimes they also filter
other particles that they can’t eat like little particles
of sediment and those particles they just eject.
They don’t eat those, they don’t digest them, but what this results
in is this filtration capacity results in clearer water
and better quality water throughout the Chesapeake Bay. So
we used to have a lot more oysters in the Chesapeake Bay than
we do now, and it was thought that when we had more oysters
in the Chesapeake Bay, all of those oysters could fill
the entire volume of the Chesapeake Bay–about 19 trillion
gallons of water–every three days. And now since we have fewer
oysters in the Chesapeake Bay, that same task is expected to take
at least a year or more. So individually, every single oyster
is a filter powerhouse, but collectively having large populations
of oysters in the Chesapeake Bay can do even more
for our water quality. A fifth fun fact about the eastern oyster
is that these animals can change their sex. So when these
oysters are smaller they tend to be male and as they grow older and
larger, they tend to transition into females. And what that means
is that on a reef where you have mostly small oysters that will
tend to be all males, on a reef where you tend to have a large
oysters, those will tend to be females and that’s why having a
large diversity in the sizes of oysters on your reef is so important
because with all males and all females, that doesn’t really
work. What we need is a good mix of small oysters and large oysters
because they tend to transition that sex throughout their
lifetime and lastly, and those of you who follow CBF and
know about this issue may already know but oysters need our
help. So the Chesapeake Bay Foundation has been involved for
many years in oyster restoration, which is our goal is
to bring back not only the populations of the oysters themselves,
but also those oyster reefs and all of the animals that
rely on them. And you can help with that. So we have volunteer
opportunities, you could become an oyster gardener and grow oysters
at your house, which then go on restoration sites. We know
that we may not be able to do those activities right now but as
soon as things settle down and we are able to continue our
restoration activities this year, we absolutely welcome you
all and welcome your help and helping to bring back one of the
Chesapeake Bay’s most iconic species the eastern oyster. So if
you want more information on our restoration work on what we’re
doing, on what we’re hoping to do In the future, you can visit
our website, which is That’s all I have
for today’s blurb on the Bay. Thank you for so much for joining
me. Stay well and be healthy.

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