Fisheries

...now browsing by category

 

Six Reasons To Celebrate World Wetlands Day

Friday, February 2nd, 2018

by Kristen Minogue

SERC scientist Lisa Schile in a marsh in San Francisco. (Courtesy of Lisa Schile.)

February 2 is most widely known as Groundhog Day, the day people all over the U.S. look to a rodent in Pennsylvania to predict the future. But it also marks a less famous holiday: World Wetlands Day, celebrated around the world since 1997, to mark the first international agreement to protect wetlands on Feb. 2, 1971. Curious why anyone would make a holiday for wetlands? Here are a few reasons to celebrate the unsung guardians along our shores.

wetland covered by grasses and yellow flowers

A wetland by the Kenai River in Alaska (Dennis Whigham)

  1. They protect our homes from storms and floods. Standing between us and the elements, wetlands soak up destructive energy from waves and storm surges. In an extreme example, it’s estimated during Hurricane Sandy wetlands along the East Coast prevented $625 million in property damage.
  2. They help keep pollution out of Chesapeake Bay and other waterways. Wetlands are sometimes called the “kidneys” of the Bay, because they’re able to filter out pollution from fertilizers, sewage, pesticides and harmful toxins before it streams into the water.
  3. red-winged blackbird among reeds.

    Red-winged blackbird. Wetlands provide a home or resting point for many birds on their migrations. (Kristen Minogue/SERC)

  4. They’re good for our drinking water. Most of the water we drink comes from groundwater beneath the surface. But wetlands can replenish it as some of their water seeps underground. And because of their filtering powers, the water is cleaner after passing through a wetland.
  5. Birds and fish love them. Herons, egrets, ducks and bald eagles all pass through Chesapeake wetlands as visitors or year-round residents. Striped bass and other popular fish rely on them for spawning ground or nurseries, as do crabs and shellfish.
  6. They store carbon. Plants soak up carbon dioxide during photosynthesis, making them critical players in fighting climate change. “Blue carbon” is the official name for carbon stored in wetlands and other coastal ecosystems. At the same time, wetland soils can also emit methane, another powerful greenhouse gas, making it tricky to know how much carbon wetlands store overall. Scientists at the Smithsonian Environmental Research Center are helping devise better ways to calculate this. So far they’ve found wetlands with more saltwater generally emit less methane and store more carbon.
  7. They’re natural air conditioning. With their lush plants and high water levels, wetlands can radiate moist air, cooling down areas nearby. This makes planting wetlands especially valuable near cities in tropical or dry climates.

Learn more:

Wetlands Can Resist Rising Seas, If We Let Them

The Blue Carbon Market Is Open

Coffee, Carbon and Crime: 22 Reasons to Love Trees

Double Trouble? Tracking the Growth of Young Oysters Stressed by Acidity and Low Oxygen

Wednesday, January 10th, 2018

by Cosette Larash

The eastern oyster (Crassostrea virginica) is one of the most important species in Chesapeake Bay. These shellfish filter the water, their reefs provide shelter for other marine species, and they’re an important seafood resource. But their numbers have hit a historical low due to overfishing, diseases like Dermo, and stressors such as hypoxia (low dissolved oxygen) and acidification (low pH).

Biologists with the Smithsonian Environmental Research Center (SERC) want to find out whether the double stresses of low oxygen and acidification can stunt oyster growth. Studies have shown that juvenile oysters grown under low oxygen are generally smaller than oysters grown under normal oxygen conditions. However, scientists still don’t know how these oysters fare over the long term. The answers could help aquaculture and oyster restoration projects all over the Chesapeake adapt to the often extreme conditions beneath the surface. Click to continue »

The Ocean Is Losing Its Breath. Here’s the Global Scope.

Thursday, January 4th, 2018

by Kristen Minogue

Dead corals and crab shells

Low oxygen caused the death of these corals and others in Bocas del Toro, Panama. The dead crabs pictured also succumbed to the loss of dissolved oxygen.
(Credit: Arcadio Castillo/Smithsonian)

In the past 50 years, the amount of water in the open ocean with zero oxygen has gone up more than fourfold. In coastal water bodies, including estuaries and seas, low-oxygen sites have increased more than 10-fold since 1950. Scientists expect oxygen to continue dropping even outside these zones as Earth warms. To halt the decline, the world needs to rein in both climate change and nutrient pollution, an international team of scientists asserted in a new paper published Jan. 4 in Science.

“Oxygen is fundamental to life in the oceans,” said Denise Breitburg, lead author and marine ecologist with the Smithsonian Environmental Research Center. “The decline in ocean oxygen ranks among the most serious effects of human activities on the Earth’s environment.”

Click to continue »

Underwater Sound Reveals Hidden Creatures
on Reefs

Friday, August 4th, 2017

by Kristen Minogue

Fish swimming through a coral reef

A wrasse fish (Halichoeres bivitattus, striped) wanders through a coral reef in Panama. (Credit: Erica Staaterman/SERC)

Coral reefs are home to some of the most colorful, diverse life on the planet. And yet, for all their fame as biodiversity hotspots, it’s estimated that divers see less than half of the fish species that live there (and that’s not counting all the invertebrates like shrimp and crabs). The invisible or “hidden half” consists of fish that aren’t active until nightfall, or conceal themselves in the reefs’ many nooks and crevices.

“Even when you are in the water looking at an animal or a habitat, there’s a lot that you can miss because it’s cryptic or hiding,” said Erica Staaterman, a marine biologist and former postdoc with the Smithsonian Environmental Research Center.

Click to continue »

The Environmental Cost of Shoreline Hardening

Wednesday, June 21st, 2017

New study shows hardened shorelines may mean fewer fish and crustaceans. 

by Ryan Greene

A split image with a wooden bulkhead on the left and a rocky riprap revetment on the right.

A new SERC study shows that both bulkheads (left) and riprap revetment (right) are associated with lower abundance of several species of fish and crustaceans in the Chesapeake Bay and the Delaware Coastal Bays. Credit: SERC

For decades, ecologists have suspected that hardened shorelines may impact the abundance fish, crabs, and other aquatic life. But now they have evidence that local effects of shoreline hardening add up to affect entire ecosystems. A new study by scientists at the Smithsonian Environmental Research Center (SERC) shows that more shoreline hardening means fewer fish and crustaceans in our waters.

Given the predictions for the coming years (i.e. rising seas and more of us living on the coast), this finding is a cause for concern. Many people will likely try to protect their land from flooding and erosion by armoring their shorelines with vertical retaining walls (bulkheads) or large rocks (riprap revetment). But as SERC researchers found in their new paper, published in Estuaries and Coasts, the impact of these hardened shorelines adds up.

Lead author and former SERC postdoc Matt Kornis likens shoreline hardening to littering. While each individual bit of trash isn’t a huge problem, the combined effect can be enormous. Kornis, now a biologist for the U.S. Fish & Wildlife Service, says the same is true of shoreline hardening. Each individual bulkhead or riprap revetment may not be catastrophic, but cumulatively they can contribute to shrunken populations of ecologically—and economically—important species like the blue crab.

“Shoreline hardening can cause loss of habitats important for young fish, like wetlands and submerged vegetation,” Kornis says. “That may be one reason we observed low abundance of many species in estuaries with a high proportion of hardened shoreline.” Click to continue »

Alaskan Alders Shape Fates of Wetlands, Streams—And Salmon

Monday, May 22nd, 2017

by Joe Dawson

007

Dennis Whigham samples horsetail plants in an Alaskan headwater stream. Credit: Ryan King/Baylor University

In Alaska, fish mean serious money. For fishermen, landowners, and the government, learning all they can about the lives of salmon could pay off in future fish harvests. There’s a lot to learn, down to how a single type of tree impacts their habitat.

The story of those habitats and trees, the alders, has been explored by SERC senior scientist Dennis Whigham and colleagues in a new study published May in Science of the Total Environment. The researchers have been studying interactions between watersheds and headwater streams for almost two decades.

Alders are most recognizable for their egg-shaped, serrated leaves. Their bark is used for tanning leather, and their wood to smoke salmon and make Fender guitars. But alders also have an outsized effect on their natural environment, transforming the chemistry and structure of wetlands and streams nearby. Bacteria in alder roots make nitrogen, an important plant nutrient, available in places where it is otherwise scarce. This can send ripple effects through entire ecosystems. In another plot twist, scientists also expect alder trees to expand northward, stirred by warmer temperatures and higher carbon dioxide from climate change. Whigham’s findings highlight the interconnectedness of wetland ecosystems, waterways, and the valuable fish that call Alaska home. Click to continue »

Volunteer Spotlight: Dave Norman

Tuesday, April 11th, 2017

by Sara Richmond

SERC citizen scientist Dave Norman stands beside a collection of samples from the bottom of Chesapeake Bay. (Sara Richmond)

SERC citizen scientist Dave Norman stands beside a collection of sediment samples from the bottom of Chesapeake Bay. (Sara Richmond)

Dave Norman’s first visit to the Smithsonian Environmental Research Center (SERC) wasn’t to help with a field trip or assist researchers in the crab lab, as he has done for the past two years. In fact, he knew very little about SERC, but was competing in a triathlon on its campus. The experience stuck with him, and when he retired a year later, he contacted SERC to ask how he could get involved as a volunteer.

The volunteer program offered a mix of science and education opportunities that turned out to be a perfect fit for Dave. He says he was part of the “Jacques Cousteau generation,” who grew up with the explorer’s books and movies, and eventually started college with plans to become a marine biologist. Those plans changed—he would practice law for 30 years before becoming a seventh-grade math teacher—but when he retired, his love of the water brought him back to the field.  Click to continue »

Ten Reasons We’re Earth Optimists After 2016

Friday, January 13th, 2017
Dawn Miller in forest

Ecologist Dawn Miller surveys trees in a SERC forest. (SERC)

by Kristen Minogue

The Smithsonian has a new resolution for 2017: Earth Optimism. This is the year the Smithsonian is celebrating environmental success stories, and shifting the focus to how we can fight battles to save species and preserve our planet—and win. Despite breaking a wide swath of climate records, 2016 gave us reasons for optimism as well. In our 2016 Year in Review, we’ve pulled out the most encouraging stories and discoveries at the Smithsonian Environmental Research Center from the previous year. Here are the top 10 that make us hopeful about the planet’s future:

Click to continue »

River Herring Have Better Shot at Comeback, Thanks to Underwater Sound

Wednesday, November 30th, 2016

by Kristen Minogue

For decades, efforts to conserve Chesapeake river herring have run into a black hole of uncertainty. Managers knew populations had plummeted, but no one knew how many remained. A team of biologists from the Smithsonian Environmental Research Center has found a way forward, recording the first complete spawning run of river herring in the Choptank River since the 1970s.

Their findings, published Tuesday in Transactions of the American Fisheries Society, give conservationists and managers a starting point: 1.3 million adult river herring migrating up the Choptank in one season.

Click to continue »

DNA Unlocks Dirty Secrets of Blue Catfish Diets

Wednesday, October 12th, 2016

by Kristen Minogue

Large blue catfish held on boat by scientist.

Blue catfish SERC biologists dubbed “Megalodon,”  which they tracked moving almost 60 miles along the Patuxent River. (Brooke Weigel/SERC)

White perch, menhaden and darters: These are just a few favorite foods of Maryland’s invasive blue catfish, according to a new study from the Smithsonian Environmental Research Center (SERC). They’re also known to gorge themselves on larvae of channel catfish—and, occasionally, juveniles of their own kind.

The study, published in the journal Environmental Biology of Fishes, used DNA barcoding to get to the gut of what blue catfish prey on. Blue catfish arrived in Chesapeake Bay in the 1960s, brought by Virginia managers to establish a fishery. They quickly developed a reputation as voracious predators, threatening to devour many popular fisheries and edge out the Chesapeake’s native white catfish. However, to discover how much they could disrupt the ecosystem, marine biologists need to know exactly what they eat. The only way to do that is to look into their stomachs, where the majority of their prey has been reduced to almost-unrecognizable slop.

Rob Aguilar would know: A biologist with SERC’s Fish and Invertebrate Lab, he’s spent the last few years dissecting blue catfish stomachs and analyzing their insides. Click to continue »