Fisheries

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Chesapeake Blue Crabs: The Shaky Recovery

Wednesday, June 13th, 2012

by Tuck Hines

Smithsonian Environmental Research Center


Few creatures in Chesapeake Bay have experienced the kind of whiplash felt by the blue crab. Having gone through a near-disastrous decline that lasted almost two decades, they made a dramatic comeback starting in 2009. But before managers could proclaim it a success, the numbers fell again. And this time, the reasons aren’t so clear.

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Toughest Shellfish in the Sea?

Tuesday, January 24th, 2012

by Kristen Minogue

Blue mussels (Credit: Meriseal)

Some species can survive just about anywhere. Take blue mussels, a group of shellfish whose habitat stretches from the Arctic to the Mediterranean. Over the last several decades, biologists have thrown all kinds of tests at them – heat, cold, saltwater, freshwater, low oxygen. They’ve even tried drying them out. Almost nothing fazes these animals. For invasion scientists trying to figure out how far they could spread, that’s a scary prospect.
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Six Endangered Species of the Chesapeake

Wednesday, November 23rd, 2011

by Kristen Minogue

Bat infected with deadly white-nose syndrome.
(U.S. Fish and Wildlife Service)

The last Western Black Rhino appeared in Cameroon in 2000. Now they’re gone, according to the International Union for Conservation of Nature, which declared the rare subspecies officially extinct Nov. 10. As thousands more species go extinct across the world every year, the Chesapeake Bay watershed is fighting to save its own endangered flora and fauna. Maryland counts 362 plants and animals on its endangered list – and that’s not including the ones that have already been wiped out from the state. Whales, bats, turtles and orchids: here are six of Chesapeake’s most wanted.
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Hunt for a Missing Nutrient

Wednesday, August 17th, 2011

by Kristen Minogue

Leviton

Intern Ginny Leviton (left) and Vienna Saccomanno sample groundwater from a drainage ditch, trying to pin down the exact spot where the nitrogen goes missing. (Credit: Tom Jordan)

The Choptank watershed has SERC researchers baffled. On the eastern shore of Chesapeake Bay, roughly a 75-minute drive from SERC, the groundwater flowing into the Choptank River passes through a cornfield – a likely source of nitrogen, a nutrient that can wreak havoc on the Bay’s ecosystem if it runs too high. But something is happening to the nitrogen here before it reaches the Bay. Nutrient ecologist Tom Jordan and his research team have spent the better part of a year trying to figure out what.
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Tracking the Chesapeake Bay’s ‘Beautiful Swimmers’

Tuesday, August 24th, 2010

As summer wanes in the Chesapeake Bay, many female blue crabs are preparing for an epic journey. Come September they will walk and swim their way toward the mouth of the Chesapeake to release their eggs. Some will travel more than 150 miles. SERC scientists have studied the blue crab’s migratory patterns for more than a decade. Their findings have revealed new insight into the life history of this important species and have helped inform management policies. Tracking these invertebrates is not easy: it involves thousands of pink plastic tags, a unique collaboration with watermen and a blue crab hotline…

NOAA Grant Funds Hypoxia and Acidification Research in the Chesapeake Bay

Monday, August 9th, 2010
Denise Breitburg holding net and standing in water surveying animals.

SERC senior scientist Denise Breitburg will lead the NOAA-funded study of hypoxia and acidification in the Chesapeake Bay.

Marine ecologist Denise Breitburg and her colleagues have thought up many novel ways to investigate the impacts of dead zones and acidification on Chesapeake Bay fish and invertebrates. Among their ideas: attaching tiny transmitters to fish and monitoring their movement in relation to oxygen and pH levels. A new $1.4 million grant from the National Oceanic and Atmospheric Administration will enable them to pursue this experiment and a host of others.
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A census of a different sort

Tuesday, April 27th, 2010

If you’re a fish or crab living in the Chesapeake Bay, it’s quite possible that at some point during your life, you’ll make your way into one of the creeks, rivers or subestuaries that feed the Chesapeake. These areas provide important nursery and spawning habitat for many of the Bay’s aquatic residents. For more than 25 years, researchers from the Smithsonian Environmental Research Center’s Fish and Invertebrate Ecology Lab have taken a weekly survey of the species that make their way into and out of one of these creeks. Its name is Muddy Creek and it feeds into the Rhode River, which flows into the Chesapeake Bay.


View Muddy Creek and the Rhode River in a larger map

To survey the animals swimming up and down Muddy Creek, the researchers use a fish weir — an expanse of nets, gates and boardwalks — that temporarily blocks aquatic traffic. Once a week, the researchers close the weir, set out the nets and identify and count all the species that get trapped. Their data go back to 1983.

This type of fine-scale surveying, that’s done on a weekly basis, is rare. It’s even more unique to have such long-term data. Many ecological studies are funded for just a few years at a time. These short time frames can make it difficult for scientists to observe changes and patterns in species populations and composition.

Human activity and environmental conditions can affect which species are swimming in Muddy Creek. The water is brackish and salinity levels change seasonally and from year to year. During winter and early spring, when freshwater flow is usually the highest, researchers will generally catch more freshwater species like bluespotted and banded sunfish – two protected species in Maryland. During periods of high salinity, researchers can catch many species indicative of the higher saline lower Bay such as, red drum, spotted sea trout, and Spanish mackerel.

In honor of the 2010 U.S. Census, we thought we’d share photos from one of this month’s surveys. The salinity on this April day was fairly low (~ 5 ppt) and nearly a dozen golden shiners (a freshwater minnow) were caught along with several estuarine-resident and a few diadromous (fish that migrate between fresh and saltwater) species. Among the highlights: a sizeable snapping turtle, many white perch in spawning condition, juvenile American eels and a parasite.

You can read more about SERC’s Muddy Creek survey on our Web site.

Hypoxic waters: Researching beyond the surface to understand the impact on fisheries

Friday, March 19th, 2010

Two summer interns in a boat measuring the water's dissolved oxygen.

Two summer interns measure the water's dissolved oxygen concentrations. Water is typically considered hypoxic if oxygen concentrations are below 2mg/L. Photo: Courtney Richmond

Habitat destruction comes in many forms. The obvious include the clear-cutting of forests and the removal of mountaintops. Then there is the damage that’s less visible, like hypoxia.

In coastal waters around the world there are more than 500 hypoxic zones. These are areas where dissolved oxygen concentrations are so low that they threaten fish, invertebrates and aquatic food webs. Some fish manage to escape hypoxic areas, but oysters, clams and other sessile creatures are simply stuck.

Hypoxia makes the evening news when there’s a noticeable fish kill. However many of its effects are more subtle. Individuals that fail to escape low oxygen zones can suffer mortality or reduced growth and reproduction. Creatures that flee can become easy targets for fishermen and predators.
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Climate change may drastically alter Chesapeake Bay, scientists say

Thursday, December 3rd, 2009

Smithsonian researchers Lori Davias and Jenna Malek collect oysters on an intertidal reef in the Chesapeake Bay. It is difficult to predict the effect of climate change on oyster populations because increasing temperatures will likely have at least two opposing effects. On one hand, intertidal oyster populations may be able to expand northward as winter temperatures rise. On the other hand, increasing summer temperatures are likely to worsen the problem of low oxygen concentrations and may reduce the extent or suitability of some subtidal habitat currently used by oysters. At this point, scientists are unable to predict whether the combination of these two factors will result in a net increase or net loss of habitat.  Photo: Sean Fate

Smithsonian researchers Lori Davias and Jenna Malek collect oysters on an intertidal reef in the Chesapeake Bay. It is difficult to predict the effect of climate change on oyster populations because increasing temperatures will likely have at least two opposing effects. On one hand, intertidal oyster populations may be able to expand northward as winter temperatures rise. On the other hand, increasing summer temperatures are likely to worsen the problem of low oxygen concentrations and may reduce the extent or suitability of some subtidal habitat currently used by oysters. At this point, scientists are unable to predict whether the combination of these two factors will result in a net increase or net loss of habitat. Photo: Sean Fate

It is one of the largest and most productive estuaries in the world, yet dramatic changes are in store for the Chesapeake Bay in coming decades if climate change predictions hold true, say a team of scientists from the Smithsonian Environmental Research Center, the University of Maryland, Pennsylvania State University, and other research organizations in a recent paper published in the journal “Estuarine, Coastal and Shelf Science”

Using forecasts of atmospheric carbon dioxide production for the coming century, the scientists predict the water of the Bay will see rising levels of dissolved carbon dioxide and higher water temperatures. As a result, climate change is expected to worsen problems of low dissolved oxygen concentrations in the Chesapeake’s water and cause sea levels to rise.
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$5 million grant from NOAA funds Chesapeake Bay research

Tuesday, November 10th, 2009

If the Chesapeake Bay could drive, it would have a severe case of road rage. The nation’s largest estuary is stressed out. That’s putting it mildly.

The Chesapeake Bay Watershed.  Landsat imagery courtesy of NASA Goddard Space Flight Center and U.S. Geological Survey.

The Chesapeake Bay Watershed. Landsat imagery courtesy of NASA Goddard Space Flight Center and U.S. Geological Survey.

Nutrient runoff, shoreline development and invasive species are just a few of the factors contributing to the Chesapeake Bay’s poor health. For decades, scientists at the Smithsonian Environmental Research Center (SERC) have been teasing out how these “stressors” impact the Bay’s plants and animals. A new $5 million grant from the National Oceanic and Atmospheric Administration (NOAA) will help bolster their efforts.
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