Posts Tagged ‘invasive species’

Zebra Mussels Discovered Near Baltimore

Wednesday, August 26th, 2015

The Maryland Department of Natural Resources (DNR) recently confirmed the presence of zebra mussels (Dreissena polymporha) in tributaries of the upper Western Shore near Middle River in Baltimore County.

On August 17, 2015, a waterman alerted DNR Biologist Brenda Davis of small zebra mussels fouling their crab gear off the Gunpowder, Bush and Middle Rivers. The next day, DNR Fisheries Habitat and Ecosystem Program biologists found numerous mussels in aquatic vegetation while trawling Middle River.

Past monitoring suggested that zebra mussels had not spread beyond the Susquehanna Flats. However, heavy rainfall in the late spring has led to lower than average salinity in the upper and middle Chesapeake Bay, potentially allowing zebra mussels to spread into habitat where they would normally not survive.

It is not yet known if zebra mussels will persist in these upper Chesapeake Bay tributaries as salinity levels increase around the Baltimore area.

For more information on zebra mussels is available at dnr.maryland.gov/invasives/ZebraMussel.asp, including a fact sheet and reporting form.

DNR asks citizens to report any suspected sightings to invavisemussels.dnr@maryland.gov.

source: Maryland Department of Natural Resources

Chesapeake Bay Zebra Mussels

Friday, May 1st, 2015

Biologists from the Maryland Department of Natural Resources (DNR) recently found a significant increase in this harmful invasive during their most recent zebra mussel monitoring effort in the upper Chesapeake Bay.

Every fall for the last three years, DNR has inspected marker buoys and anchors as they are brought aboard the Department’s buoy-tending vessel, the A.V. Sandusky, for winter storage. This past fall, there were approximately 35 times more attached mussels and colonized anchors compared to the year prior.

Also during this time, two alert watermen submitted specimens of zebra mussels that had colonized their fishing gear on the Susquehanna Flats. Citizen sightings – such as zebra mussel larvae entering water system intakes, and adults attaching to infrastructure – help DNR assess trends in the population.

According to DNR, mariners who use the lower Susquehanna River and upper Bay can help prevent the spread of zebra mussels to other Maryland waters by taking these precautions:

– Remove all aquatic plants and mud from boats, motors and trailers; and put the debris in trash containers.

– Drain river water from boat motors, bilges, live wells, bait buckets and coolers before leaving to prevent these aquatic hitchhikers from riding along.

– Dispose of unused live bait on shore, far from the river or Bay or in trash containers.

– Rinse boats, motors, trailers, live wells, bait buckets, coolers and scuba gear with high pressure or hot water between trips to different water bodies.

– Dry everything at least two days, and preferably five days, between outings.

– Limit boating from place to place – particularly between the Susquehanna and upper Bay to other water bodies in Maryland – where zebra mussels haven’t invaded.

DNR also asks that people who live, recreate and work on the water report any suspected sightings to invasivemussels.dnr@maryland.gov or 410-260-8604. More information is available at dnr.maryland.gov/invasives/ZebraMussel.asp.

In Maryland, zebra mussels are currently restricted to the lower Susquehanna River and upper Chesapeake Bay.

source: Maryland Department of Natural Resources

Chesapeake Bay Invasive Catfish Research

Tuesday, May 20th, 2014

Initially introduced for sportfishing in several Virginia tributaries, blue and flathead catfish are considered invasive in the Chesapeake Bay. Since their introduction, their range and population have increased dramatically. Blue and flathead catfish are now top predators in several river systems of the Chesapeake Bay.

In order to learn more about how these fish may be affecting the Bay, the NOAA Chesapeake Bay Office has funded several studies to take a closer look at the biology and feeding habits of these fish.

Completed Projects:

A project conducted by Virginia Commonwealth University researched what kinds—and how much—prey blue and flathead catfish consume, and how that may change throughout the year. The VCU researchers found that these catfish may contribute to substantial losses of key Bay fishery species including white perch, menhaden, and blue crabs. The researchers also developed recommendations on how the effects of invasive catfish might be mitigated, including the experimental use of electrofishing to increase commercial harvest.

Researchers at the Virginia Institute of Marine Science (VIMS) focused on whether contaminant burdens in blue catfish could pose a human health risk if people eat these fish. Like other larger fish that live for a relatively long time, blue catfish may “bioaccumulate” mercury and other contaminants to such levels that cause human health concerns. The VIMS researchers explored how much of these contaminants blue catfish bioaccumulated in the Potomac, Rappahannock, and James Rivers. The research found that contaminant levels in fish under 32 inches are under current consumption advisory levels.

Another VIMS research team quantified the growth of individual blue catfish by tracking the length of fish at different ages and how much fish of a given length weighed. Fish collected and measured in the Potomac, Rappahannock, York, and James Rivers had slightly different growth characteristics—but overall, they grew to be impressively long and heavy fish. The fish that were measured sometimes reached 13 inches by their fifth year and nearly 40 inches by their 17th or 18th year. Better understanding these rapid growth rates will help fishery managers asses and identify potential impacts blue and flathead catfish could have on the ecosystem as these fish quickly approach large sizes and apex predator status.

Projects under way:

VIMS research is estimating the population numbers of blue catfish in the James River, as well as their survival rates. They are doing this by tagging blue catfish and working with a waterman to track them when they are recaptured.

Researchers at the Smithsonian Environmental Research Center are investigating how blue catfish fit into the Chesapeake Bay’s food web, including cataloging undigested fish prey items from blue catfish stomachs. Work by SERC scientists to date has been conducted in the Patuxent, Nanticoke, Sassafras Rivers and Northeast/Swan Creek/Susquehanna Flats.

Results from this research are being used by the Chesapeake Bay Program’s Sustainable Fisheries Goal Implementation Team, which brings together resource managers and other experts from around the watershed to discuss topics related to fishery management in the context of the most up-to-date science.

source: NOAA Chesapeake Bay Office

Maryland Invasive Catfish Public Awareness Campaign

Wednesday, May 7th, 2014

In April, the Maryland Department of Natural Resources launched a statewide campaign to educate citizens about invasive Blue and Flathead Catfish, their impact on native species, and what anglers can do to help.

To kick off the effort, partners and stakeholders joined DNR staff for a catfish cooking demonstration and tasting at Smallwood State Park on the Potomac River.

“Increasing in population and range, both blue and flathead catfish are now abundant in the Chesapeake Bay, threatening the natural food chain of our ecosystem and causing concern among fishery managers,” said DNR Deputy Secretary Frank Dawson.

DNR developed the outreach program to help anglers identify and catch these invasive species, understand the importance of regulations that prohibit their transport, and encourage anglers to keep the fish instead of releasing them alive.

The Chesapeake Bay Program’s Sustainable Fisheries Goal Implementation Team and the Atlantic States Marine Fisheries Commission have both formerly recognized the need to address the threat to native species by working to reduce invasive catfish densities and range.

In addition to establishing more than 150 educational/cautionary signs at water access points and kiosks statewide, the State is escalating efforts to market Maryland’s fledgling commercial catfish fishery.

Catfish dishes from Chef Michael Stavlas of Hellas restaurant in Millersville and Executive Chef James Barrett of Azure in Annapolis provided attendees with a taste of this delicious invader.

Blue and Flathead Catfish were introduced into the Chesapeake Bay ecosystem in the 1970s and 80s. Flatheads found ideal conditions in the Occoquan River, a small tidal Potomac tributary in Virginia and were recently identified in the non-tidal Potomac River near Williamsport. Flatheads have also become established in the Lower Susquehanna River. Blue Catfish are now in most of the major tributaries of the Chesapeake Bay as a result of their natural range expansion and possibly through illegal introductions by fishermen seeking to establish fisheries in other waters.

There is no limit to the number of catfish an angler can catch and keep. The Maryland Department of the Environment advises limiting monthly Blue Catfish consumption for adults to: four fish under 15 inches; two between 15 and 24 inches; or one between 24 and 30 inches; and none over 30 inches due to the possibility of chemical accumulation in these species. The recommended monthly limit for children is: four under 15 inches; one from 15 to 24 inches; one fish every other month from 24 to 30 inches; and none over 30 inches.

For more information on invasive species in Maryland, visit dnr.maryland.gov/invasives.

Maryland Department of Natural Resources

2012 Maryland Snakehead Contest Results

Friday, March 8th, 2013

Three anglers recently won nearly $300 in prizes for catching and killing snakehead fish in the Maryland Department of Natural Resources’ (DNR) 2012 Snakehead Contest.

During the contest, 256 anglers removed nearly 600 fish from the Potomac River system. To enter, participants shared their experiences on the Department’s Angler’s Log, reporting how they caught the invasive fish, where they found them, some even sharing delicious ways to prepare them.

The contest ran from March 1 to November 30, 2012, with DNR choosing the winning anglers at random. Kasie Taylor won a $200 Bass Pro Shop gift card; Jerry Lester won a 2013 Maryland State Park Passport worth $75; and Les King won a 2013 fishing license donated by the Potomac River Fisheries Commission.

DNR launched the contest in 2010 to monitor how far the species has spread and encourage anglers to capture and remove snakeheads from Maryland waters.

The Department plans to add the snakehead to the list of species in the Volunteer Angler Survey, which uses anglers’ catch data to help fisheries managers assess fish populations. For the 2013 fishing season, snakehead anglers who log their catches on the Angler’s Log will be automatically entered in the Volunteer Angler Survey with the chance to win prizes. The single-species Snakehead Contest therefore, has been discontinued.

source: MD DNR









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