Fisheries

...now browsing by category

 

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 »

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 »

When the Going Gets Tough, Baby Oysters Get Growing

Friday, September 23rd, 2016

by Kristen Minogue

Andrew Keppel

Andrew Keppel (Credit: Rebecca Burrell/SERC)

Baby oysters are a lot stronger than they look. Living mainly in shallow coastal waters, where oxygen plummets and acidity spikes on a nightly basis, building a decent shell should be a challenge. But after a couple of weeks, young oysters are often able to adjust to the harsh conditions—and, sometimes, even grow more quickly to make up for lost time.

The discovery came from a team of marine ecologists at the Smithsonian Environmental Research Center (SERC), who published the new study in the journal PLOS ONE.

“It’s really impressive what these oysters are able to do in terms of acclimating to potentially harmful conditions,” said lead author Andrew Keppel, who worked on the project as a graduate student and later technician in SERC’s Marine Ecology Lab, before becoming an oceanography lab manager at the U.S. Naval Academy. Click to continue »

Making Noise About Marine Sound Pollution

Thursday, August 4th, 2016
SERC intern Michelle Hauer sets up her soundscape ecology tank experiment

SERC intern Michelle Hauer sets up her soundscape ecology tank experiment (Photo: Emily Li/SERC)

by Emily Li

In high school, Smithsonian Environmental Research Center intern Michelle Hauer fell in love with sound. She discovered the cello, which she insisted on bringing to her internship this summer despite having limited space and housing. But her affair with sound didn’t stop there, even as she was exploring her interest in science. While still in high school, she wrote a paper on the effects of naval sonar on marine mammals. Then, while attending DePaul University, Hauer came across the relatively new field of soundscape ecology through a Chicago-based organization called Chicago Wildsounds—and she hasn’t looked back. Now, as a summer intern in SERC’s Fish and Invertebrate Ecology Lab, Hauer is studying the darker side of sound by researching how noise pollution can affect marine wildlife in the Chesapeake Bay and beyond.

Click to continue »

An Acid Test for the Coasts

Monday, August 1st, 2016
Graham cleans her equipment of marine organisms

SERC intern Jasmin Graham cleans her equipment of marine organisms (Photo: Emily Li/SERC)

by Emily Li

Watching educational programs like Animal Planet or That’s My Baby—a series that documents pregnant animals—might evoke memories of flickering classroom projectors for most. But for Jasmin Graham, an intern with the Smithsonian Environmental Research Center (SERC), these shows were her childhood. Her love for marine science and wildlife followed her through high school science fairs and university research on shark genetics at the College of Charleston. Now, at an internship with SERC’s Ocean Acidification Lab, she studies acidification not in the open ocean, but in a far more dramatic arena, where the marine celebrities she grew up with may be at risk.

Click to continue »

Invasive Ascidians Are a (Potentially Delicious) Recipe for Disaster

Thursday, July 14th, 2016
Christina Simkanin prepares to dive into a marina to survey for ascidians

Christina Simkanin prepares to dive to survey ascidians. (Credit: Natalia Filip, University of Victoria, BC, Canada)

by Emily Li

Smithsonian biologists are on the trail of invasive ascidians. But with roughly 2300 species worldwide, describing these marine filter feeders (also known as “tunicates” or “sea squirts”) for a Most Wanted sign is tricky. Some ascidians are solitary; some are social. Some breed sexually, some asexually. Some, like Botrylloides magnicoecum, form large colonies of what look like octopus tentacles ringed in gold and highlighter blue. Others, like Rhopalaea crassa, resemble a cross between ghostly butterfly cocoons and pastel-colored pencil grips, while Polycarpa aurata is bulbous and mustard-yellow, with navy-blue veins that flare into trumpets.

When they invade new territory, ascidians can leave trails of damage in their wakes—but not always in ways scientists predict. In a new study published in the July issue of Marine Biology, a team of Smithsonian researchers, including marine ecologist Christina Simkanin of the Smithsonian Environmental Research Center (SERC), tracked their invasions across North America.

What they found seemed simple at first: North America’s 26 non-native ascidian species have spread so much they’re now established along nearly 3000 miles of its coastlines. But a few surprises were hiding in the details.

Click to continue »

Key to Oysters’ Future Lies in Past

Monday, May 23rd, 2016
Oyster midden

Typical American Indian oyster deposit, roughly 1,000 years old. (Torben Rick/Smithsonian)

by John Gibbons

Oysters have provided food for humans for millennia, and play an enormous role in sustaining estuaries around the world. Yet after more than a century of overfishing, pollution, disease and habitat degradation, oyster populations in the Chesapeake Bay and elsewhere have suffered dramatic declines. But for thousands of years,American Indians in the region harvested the shellfish from the Bay sustainably—a discovery published Monday that could offer clues for future oyster restoration.

Little is known about oyster populations prior to the late 1800s. On May 23 a team of Smithsonian scientists and other researchers published the first bay-wide, millennial-scale study of oyster harvesting in the Chesapeake in Proceedings of the National Academy of Sciences. Using fossil, archaeological, and modern biological data, the team was able to reconstruct changes in oyster size from four timeframes: the Pleistocene (780,000-13,000 years ago), prehistoric American Indian occupation (3,200 – 400 years ago), historic (400 – 50 years ago) and modern times (2000 to 2014).

Click to continue »