For Chesapeake oysters, the way forward leads back—through the fossil record

NOVEMBER 21, 2019 

by Joseph McClain, The College of William & Mary

Big oyster/old oyster: Rowan Lockwood displays one of the 900 oyster fossils studied in a palaeobiological analysis of the oysters of the Chesapeake Bay. She and co-author Roger Mann believe fossil beds paint a picture of the oyster population of a healthy Chesapeake ecosystem. Credit: Stephen Salpukas 

Oysters once dominated the ecosystem of the Chesapeake Bay, and it would be difficult, if not impossible, for the Bay to return to full ecological health without restoring Crassostrea virginica to its glory days of the Chesapeake's apex filterer. 

Rowan Lockwood and Roger Mann believe that you have to go back to the fossil record to get your head around the idea of a fully oystered Chesapeake. Their paper, "A conservation paleobiological perspective on Chesapeake Bay oysters," appears in a special issue of Philosophical Transactions B, titled ""The past is a foreign country: how much can the fossil record actually inform conservation?". 

Lockwood is a professor in William & Mary's Department of Geology, which she chairs. Mann is a professor in the Department of Fisheries Science at the university's Virginia Institute of Marine Science. Their collaboration melds Lockwood's examination of long-dead oysters in the Chesapeake with Mann's expertise in the state of oysters today. 

Their paper looks at 900 fossil oysters from three Pleistocene reefs and compares them to oysters today. Lockwood and Mann employ conservation paleontology methods to create a model of how the Chesapeake Bay looked and functioned long before humans. 

Basically, the prehistoric oysters were bigger and more numerous—and therefore filtered more water. 

"This is clearly a case of bigger is better," Lockwood said. "Larger oysters filter significantly more water, remove more algae, produce more offspring, buffer more acidic bay water, recycle more nitrogen and possibly even bury more carbon than smaller ones." 

Read on

Study shows invasive blue catfish can tolerate high salinities

NOVEMBER 6, 2019

by David Malmquist, Virginia Institute of Marine Science

A new study by researchers at the Virginia Institute of Marine Science warns that blue catfish—an invasive species in several Chesapeake Bay tributaries—tolerate salinities higher than most freshwater fishes, and thus may be able to expand their range downstream into mainstem Chesapeake waters, and from there into new Bay tributaries and even Delaware Bay.

Conducting the study, reported in the November 5th issue of PLOS ONE, were Ph.D. student Vaskar Nepal of William & Mary's School of Marine Science at VIMS and VIMS fisheries professor Mary Fabrizio.

Nepal and Fabrizio undertook the study to better constrain the salinity tolerance of blue catfish in their non-native Chesapeake Bay habitat. The value used in the 2014 report that currently guides management of invasive Bay catfishes was based on a study of blue catfish from their native range: the fresh waters of the Mississippi River basin. Evidence suggests that populations of "blue cats" and other fishes may become more salt tolerant when exposed to brackish estuarine waters.

"We wanted to see how long blue catfish can survive at a given salinity to help us better understand the extent to which they can colonize areas other than those where they were originally stocked," says Nepal.

Continued

For the first time, biologists track cownose rays to Florida and back

August 23, 2018, Smithsonian

Every summer, cownose rays stream into Chesapeake Bay to mate and give birth to their pups. When autumn comes, they disappear—presumably to migrate south, but no one knew for certain where they spent the winter. Now, after a three-year tagging study published Aug. 23 and led by the Smithsonian Environmental Research Center (SERC), scientists have solved the mystery. Cownose rays all along the Atlantic winter near Cape Canaveral, Florida, and it is likely they return to the same spots each summer.

Cownose rays are large stingrays native to the Chesapeake, with dark brown or olive-gray backs and white bellies. They reproduce slowly. Most mothers give birth to only one pup a year, and they do not mature until age 7 or 8, making them vulnerable to intense fishing or sudden population declines. And yet cownose rays have been dogged by controversy. In the early 2000s, they were saddled with partial blame for oyster declines because their diet includes shellfish. (Later studies cleared their names. Oysters had been declining years before cownose rays became more abundant.) Later, in 2015, bowfishing tournaments for cownose rays began raising alarm among some Marylanders. In response, the Maryland government voted to become the first state to create a fishery-management plan to conserve the cownose ray.

"Because of the slow birth rate, we know that if we don't manage them, and instead harvest them in a way that heavily impacts the population and causes a population decline, it'll take a long time for them to recover," said Matt Ogburn, SERC marine biologist and lead author of the study. "If we lose something important, we could lose it for decades."

The new study, published in Marine Ecology Progress Series, marks the first time scientists have tracked cownose ray migrations along the Atlantic coast for a full year or more. Knowing where they go every year will help fill in some longstanding knowledge gaps about the rays, as Maryland officials decide how to manage them. It is part of the Smithsonian's new Movement of Life Initiative. Scientists from the Virginia Institute of Marine Science (VIMS) and Savannah State University also joined the effort.

Read more at:

100 Million Year Old Seawater Discovered Under Chesapeake Bay

November 22, 2013

redOrbit Staff & Wire Reports – Your Universe Online

US Geological Survey (USGS) hydrologists drilling into the largest crater in the country have stumbled across an amazing discovery – the oldest body of seawater ever unearthed.

The water, which according to Discovery News is at least 100 million years old, was found over one kilometer beneath Chesapeake Bay in Virginia. The seawater is believed to have come from the earliest days of the Atlantic Ocean and was hidden beneath a more recent, 56-mile-wide impact crater near the bay’s entrance.

The USGS investigators did not realize how old the water was until they completed an analysis of the chemicals it contained. As it turns out, the water held forms of chloride and bromide, as well as other chemicals that helped them determine that the liquid is, in fact, from the Early Cretaceous Period. While older water has been discovered in Canada, the newly discovered crater is now officially the oldest large body of water on Earth.

Read on ...

Chesapeake Bay Developmental Area for Young Sea Turtles - via Herp Digest

Feb 13, 2013   (Photo caption-Unfortunately was of group of eastern painter turtles) |Sea turtles swim near Berlin. A symposium was held last week in Baltimore to bring attention to the critical issues affecting sea turtles and diamondback terrapins, the Maryland state reptile, in the Chesapeake Bay.

Written by

ANGELA HARVEY

Capital News Service

Sea turtle number 32 had a small part of its front left flipper amputated last week because a joint lesion has not healed since the reptile was brought to the National Aquarium’s Marine Animal Rescue Program in November.

“It’s an infection in the joint so we don’t want it to spread and then have to amputate the entire flipper,” said Amber White, a husbandry aide. “As you can image that would impair his swimming ability.”

The surgery on Friday went well. Number 32 has stitches in the flipper and has resumed its normal swimming activities, while stitches on the turtle’s front right flipper are healing well after a similar amputation was done at the animal care center in January.

Number 32 was found stranded off the coast of Cape Cod, Mass., White said. Its rehabilitation carries high stakes because it is a Kemp’s Ridley sea turtle, the smallest and most critically endangered species of sea turtles.

The U.S. Fish and Wildlife Service has determined the Kemp's Ridley turtle's nesting numbers started declining dramatically after 1947, reaching a low of 702 nests in 1985. Since the mid-1980s, the number of nests laid in a season has been increasing. There were 20,800 documented nest in 2011. This increase is attributed to nest protection efforts and regulations requiring the use of turtle excluder devices in commercial fishing trawls.

Sea turtles were in the public eye last week when more than 1,000 scientists, researchers, conservationists, lawmakers and students from 80 different countries came to Baltimore for the 33rd Annual Symposium on Sea Turtle Biology and Conservation, said Dr. Ray Carthy, president of the International Sea Turtle Society and assistant unit leader of the Florida Cooperative Fish & Wildlife Research Unit.

The National Aquarium of Baltimore and the Virginia Aquarium & Marine Science Center cooperated on the symposium to bring attention to the critical issues affecting sea turtles and diamondback terrapins, the Maryland state reptile, in the Chesapeake Bay.

"The water quality and health of the Bay affects all of us because sea turtles are important sentinels of the ecosystem,” Carthy said. “The Bay is an important foraging and nesting area for turtles, as well as an important developmental area for young turtles.”

The injuries turtles endure as a result of many of the issues discussed at the symposium can be seen at the aquarium's rescue program. It has treated and released turtles and other marine animals stranded in Maryland for 21 years. It also is a part of a regional stranding network, so it can take the overflow from other animal care centers from Maine to Virginia, said Jennifer Dittmar, the stranding coordinator.

The animal care center has seven juvenile turtles in its care: two loggerheads, two greens, and three Kemps. All came to the program in November and December after being stranded in Cape Cod, White said.

The turtles are being treated for a variety of conditions such as cold stunning -- the same as hypothermia in humans -- respiratory infections and the exposure of shell bone, White said. Rehabilitation time depends on the turtle's condition, but typically lasts five to six months. During their stay the turtles’ energy levels and respiratory rates are closely monitored and program veterinarians perform surgeries, ultrasounds, endoscopies and other procedures as necessary, White said.

The staff tries to mimic the turtles’ natural environment as much as possible. Currents are created by the tank’s water system. To replicate sea kelp, car wash strips are attached to PVC pipes, and little tunnels were made for the turtles to hide under.

A number painted on the shell identifies each turtle. Their sex cannot be determined until they are a little older -- males have longer tails. They have yet to be named, so White affectionately refers to the group as the brat pack, in tribute to classic 1980s movies.

Many of the staff and researchers from the National Aquarium and the program attended the symposium, where this year’s theme was connections. Carthy said Baltimore was the ideal location for international conservationists and scientists to meet with federal workers to share research and discuss protection and conservation policies.

“The sea turtle community is global, and many of the laws passed in the United States affect conservation efforts worldwide,” Carthy said. “Having this event in Baltimore allows people in the sea turtle community to easily meet and exchange ideas with federal workers.”

The exchange continued with a teachers workshop, held at the National Aquarium and run by the Virginia Aquarium’s education department, that drew about 30 educators, most from Baltimore city and county areas. Educators were introduced to the lives of sea turtles in the Chesapeake Bay as they discussed how to educate students about the health of the estuary.

“We want to help educators incorporate sea turtles and conservation careers into their curriculum,” Carthy said, “and it’s personally important to me to target minorities that are underrepresented in the conservation fields.”

Artwork made by students from six Maryland schools was on display at the symposium as part of a contest with the theme of how humans can help sea turtles overcome threats they face.

In the Chesapeake Bay and Atlantic Ocean sea turtles can face entanglement, cold stunning, bycatch, habitat denigration, and agricultural and industrial runoff causing dead zones, Carthy said.

These are some of the dangers number 32 will face when it is eventually released. After the surgery is complete, the program staff will wait for signs that it can hunt and forge and is healthy enough to return to the wild.

White said there will be a test.

“We drop in live crabs. It’s not easy prey, they fight back.”

Our Bay: Monster catfish may cause monster problem

Blue catfish are monsters — in more ways than one.

They grow to gargantuan sizes, reeling in anglers who live for the thrill of catching a giant trophy fish that can weigh more than a small child.

But they’re also an invasive species that can wreak havoc on the Chesapeake Bay’s food chain, gobbling up small fish and leaving little for other big fish to eat.

Regulators in Maryland and Virginia are trying to control these whiskery invaders, and federal officials who work on the bay have officially declared blue catfish as a problem that needs fixing.

“They’re showing up pretty much everywhere,” said Don Cosden, chief of inland fisheries for Maryland. “We’ve documented them in the Patuxent River, the Nanticoke, the Choptank, the Upper Bay. We have reports of blue cats being caught in the Upper Bay.”

The trouble with blue catfish turning up around the bay is that they are not native to the bay. Blue catfish are native to the Mississippi River system.

It’s believed that blue catfish were stocked in Virginia in the 1970s to provide a good fishing opportunity for recreational anglers — before officials realized the problems blue catfish could cause. It’s possible that rogue introductions have caused the population to spread further.

‘No getting rid of them’

Blue catfish (Ictalurus furcatas) have gray-blue backs and silver or white bellies, as well as barbels on the chin that look like whiskers.

And they can grow large. Very large.

Angler Shawn Wetzel of Pennsylvania set a Maryland state record for blue catfish in February with an 80 pound, 12 ounce blue cat he caught on the Potomac River. He beat the old record by 13 pounds.

But that’s nothing compared to Virginia’s blue catfish. The world record of 143 pounds was set in Virginia’s Buggs Island Lake near the North Carolina border last summer.

Blue catfish get so big because they are not picky eaters. Maryland’s Department of Natural Resources has done a few stomach surveys — they see what’s inside a dead fish — and found all sorts of fish, including at least one northern snakehead, a fellow problematic invader.

Blue catfish, normally a freshwater species, have adapted to some slightly salty areas in the bay.

“If they can adapt to a new environment and they can find a niche, there’s no getting rid of them,” Cosden said.

It’s not known exactly how much blue catfish might be displacing native predator fish or nonnative predator fish that aren’t causing problems, such as channel catfish.

Maryland officials are sort of lumping blue catfish into the same category as the toothy northern snakeheads, asking anglers to catch them and kill them as frequently as possible. Even eat them, if you like.

While there’s an official kill-on-sight rule for snakeheads, there’s no such death sentence for blue cats. Still, “we prefer that you kill it and eat it,” Cosden said.

Read on:  http://www.hometownannapolis.com/news/env/2012/03/24-06/Our-Bay-Monster-catfish-may-cause-monster-problem.html

By PAMELA WOOD, Staff Writer

Alarming 'dead zone' grows in the Chesapeake

Alarming 'dead zone' grows in the Chesapeake
By Darrul Fears, July 24,2011 Washington Post

A giant underwater "dead zone" in the Chesapeake Bay is growing at an alarming rate because of unusually high nutrient pollution levels this year, according to Virginia and Maryland officials. They said the expanding area of oxygen-starved water is on track to become the bay's largest ever.
This year's Chesapeake Bay dead zone covers a third of the bay, stretching from the Baltimore Harbor to the bay's mid-channel region in the Potomac River, about 83 miles, when it was last measured in late June. It has since expanded beyond the Potomac into Virginia, officials said.

Especially heavy flows of tainted water from the Susquehanna River brought as much nutrient pollution into the bay by May as normally comes in an entire average year, a Maryland Department of Natural Resources researcher said. As a result, "in Maryland we saw the worst June" ever for nutrient pollution, said Bruce Michael, director of the DNR's resource assessment service.

That's bad news for biologists who monitor the bay and horrible news for oysters and fish. Dead zones suck out oxygen from deep waters and kill any marine life that can't get out of the way.
Nutrient pollution from chemicals such as fertilizers provide a feast for bay algae, which bloom and die in a rapid cycle. They decompose into a black glop that sucks oxygen out of deeper waters. Oysters and other shellfish are doomed in dead zones. Fish and crabs can skitter to surface waters where there's more oxygen, but some don't make it, Michael said.

No one knows how many marine creatures perish in dead zones, "because we just don't know what goes on down there," Michael said.

"We know it's not good habitat for fish," he said. Chesapeake Bay shad, rockfish, oysters and crabs are already threatened species.

"If there's not good habitat, they're stressed and they
won't reproduce,'' Michael said. "They're more susceptible to disease and won't eat. We want them to eat a lot of food and reproduce and grow."
Donald Boesch, president of the Center for Environmental Science at the University of Maryland and an expert on dead zones, said this year's water flow will rank at least among the five largest, a result of heavier-than-normal rains and snow melt mixed with high amounts of nitrogen, phosphorus and sediment.

Dead zones are a yearly occurrence caused by pollution in water that runs off cities and farms. They form in summer and usually dissipate in fall, sucking oxygen from deep waters and leaving dead oysters, clams, fish and crabs in their wake.

A similar phenomenon is taking shape in the Mississippi River Valley, where tons of chemical fertilizer run off huge industrial farms, the Nature Conservancy announced recently. Findings by researchers at Texas A&M University support predictions that remarkably heavy rains and snow melt in the valley will create the largest-ever dead zone in the Gulf of Mexico.

Dead zones run the length of the Atlantic Coast. Environmentalists say they are a testament to reports that pollution loads from ever-expanding cities and suburbs are growing and, in some cases, creating a monster.

Chessie (the manatee) returns to Chesapeake Bay (via Chad Arment)

Famous Manatee Sighted in Chesapeake Bay After Long Absence

Gainesville, Fla. – A manatee spotted this week in Calvert County, Maryland is the same one that first made waves 17 years ago when he appeared in Chesapeake Bay just before the onset of winter and later had to be rescued.


Named "Chessie," the manatee's identity was verified by U.S. Geological Survey biologist Cathy Beck, who used photos taken July 12 and matched them with Chessie's photographic record in a USGS manatee database. Chessie's tell-tale markings include a long, gray scar on his left side.

USGS scientists regularly document manatee sightings to analyze life histories of individuals as part of an ongoing effort to estimate adult survival rates of the endangered Florida manatee. Yet, biologists were surprised to find it was Chessie, a well-known manatee who has not been seen for about 10 years. The last time USGS researchers confirmed a sighting of Chessie was after he swam through Great Bridge Locks in Virginia on August 30, 2001.

By then, Chessie was already well known. After being found in the Kent Narrows area of the Chesapeake Bay in the fall of 1994, researchers became concerned about how he would fare in the oncoming winter. Manatees suffer negative health effects when they endure water temperatures below 68 degrees for any length of time. With water temperatures dropping in the bay, the Marine Animal Rescue Program at the National Aquarium worked with the U.S. Fish and Wildlife Service, Seaworld Orlando, and the Maryland Department of Natural Resources to rescue Chessie. He was cared for at the aquarium for several days before being successfully flown back to Florida and released.

The current sighting is not driving any plans to rescue Chessie, as the water is still warm and manatees typically work their way back down the eastern seaboard to Florida on their own when cooler weather sets in.

Scientists are not sure whether Chessie visits the Chesapeake Bay every year. After Chessie's 1994 rescue, USGS tagged him and found that he did migrate back to Chesapeake Bay the following spring. Much of what scientists know about manatee migration comes from studies that use radio and satellite tags to reveal key facts about manatees' habitat needs, such as how they use seagrasses and winter refuges.

In general, scientists believe manatee migration from Florida to the Chesapeake Bay may not be unusual, and in fact Chessie was named after legendary sightings of a "sea monster" in the Chesapeake Bay throughout the twentieth century.

Chessie was spotted and identified this year due to the help of two bystanders who took pictures of him and contacted Jennifer Dittmar, the National Aquarium's Coordinator for the Northeast Marine Mammal Stranding Network. Dittmar forwarded Beck photos of the manatees head and back.

http://www.usgs.gov/newsroom/article.asp?ID=2855

Two Million Fish Found Dead In Maryland

Around two million fish have died in the Chesapeake Bay area in Maryland, just days after two similar incidents elsewhere in the US baffled scientists.


Officials are now trying to find out what happened.


Maryland Department of the Environment spokeswoman Dawn Stoltzfus told Sky News Online that at the moment it does not look like pollution is to blame.

She said: "The dead fish are mainly juvenile spot fish, and they can't survive very cold water temperatures. Typically they should have left the bay by now.

"Our working theory, that looks pretty strong, is that it's been caused by cold water stress."

This mass "fish kill", as it is called, happened after water temperatures plunged to near record lows in the area in late December, but scientists have yet to prove conclusively that this was the cause.

Elsewhere in the US, large numbers of sudden bird and fish deaths have perplexed biologists.

Just days ago, an estimated 500 small birds, mostly blackbirds, fell out of the sky in Louisiana.

On New Year's Eve in Arkansas, thousands of the same species were found, followed by the discovery of around 100,000 dead fish in a river about a hundred miles away.

Officials think that power lines may be to blame for the Louisiana deaths, and fireworks or lightning could have been responsible for what happened in Arkansas.

The events are not being linked, but similar scenarios across the world are adding to the mystery.

Officials reported around 50 jackdaws had been found dead on a street in Sweden, and other unexplained mass fish deaths have occurred recently in Brazil and New Zealand.

Large fish kills have happened before in Chesapeake Bay, most notably in 1976 and 1980. Officials acknowledged that the most recent incident is the biggest since those events.

Hannah Thomas-Peter, Sky News Online

http://news.sky.com/skynews/Home/World-News/Two-Million-Fish-Found-Dead-In-Chesapeake-Bay-Maryland-After-Birds-Die-In-Arkansas-And-Louisiana/Article/201101115880847?lpos=World_News_First_World_News_Article_Teaser_Region_3&lid=ARTICLE_15880847_Two_Million_Fish_Found_Dead_In_Chesapeake_Bay_Maryland_After_Birds_Die_In_Arkansas_And_Louisiana