Fisheries Habitat Program – Maryland Department of Natural Resources

Fisheries Habitat Program – Maryland Department of Natural Resources


[Music – Out of This World by Mark Steven Cook and Louise Carmen Cook] Right now, the crew is out here pulling the
sein. This is the kind of standard technique that
the department’s used since 1954 for investigating all kinds of fish and we use it as well. In our case, we use this to look at the use
of habitat in shallow water and systems. And then we’ll pull a trawl, later, out in
the channel to look at how the deep water habitat is used or if it’s used. Often in developed tributaries what happens
is, this is about the only habitat that’s viable for most of the fish and crabs.
and the channel waters will have oxygen problems and will have very few or no fish at all
So this is a way of kind of looking at what the community should be in the system
and then comparing this with what we see out in deeper water. This site hasn’t done much this year, for whatever reason. Right now, we’re pulling a trawl in what we
call the deep water habitat here, it’s not terribly deep it’s about 17 feet in this case. But these trawls in this habitat give us some
idea of what the fish community and the crabs are doing in the deeper waters
then we sein in the shallower waters. Typically we have each sub-estuary has four
sites with a site starting at about as far upstream as we can we can run the boat
and then being evenly spaced downstream. We don’t go all the way down to the mouth
because we don’t want water coming in from the bay. We want to get the water that’s being affected
by what’s going on in the watershed So we typically our furthest site down is
maybe about two-thirds of the distance to the mouth. Carrie’s taking some basic water quality right
now. She’s got a GPS to get our location and then
it’s just a basic water quality scan of dissolved oxygen, temperature,
pH – which is basically a measure of the acidity or alkalinity of the water,
Conductivity – which is related to salinity. It’s the ability of water to conduct electricity. These basic parameters can tell us a fair
bit about the habitat conditions in a system In a system that has the saltier water brackish
water, like the Tred Avon, where we are today. Disolved oxygen is very key. Other places, we may, like in fresh tidal
tributaries we may key in more on conductivity it’s very sensitive to
detection of road salt, which is actually a pollutant, that becomes
increasingly a problem in urbanizing freshwater tributaries. Essentially this gives us some idea of the
habitat conditions Although it’s actually far more complex than
just this basic scan This does give us some idea of how the system
might be changing under the stress from being developed. Well, this is your typical fish community
In a brackish tributary it’s actually we’ve had a good year for Croakers
it appears. There’s adult white perch, sometimes we get
some large ones or some crabs in there. There’s a large bay anchovy
And also young of year striped bass. So this habitat is extensively used.
It’s an important place for these fish to grow up and become larger
And it’s all linked into how the Watershed – how intact it is
and negatively linked to how developed it is.

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