ANNAPOLIS, MD (December 1, 2015) – Exotic species are in the news almost daily. They can be found in our parks and even in our own backyards. Sadly, many of them are so common, most people do not realize that they do not belong here. To be invasive, an organism must have evolved somewhere other than where it's found in Maryland, have a negative impact on the environment it moves into, and have been moved, deliberately or by accident, by people.

For example, when the brown marmorated stink bug silently slipped into the U.S., it was years before it was correctly identified as an exotic species. By that time it was already becoming a pest in orchards and vineyards.

One of the first questions about most invasive species is "How did it get here?" — quickly followed by "Could it have been prevented?" The majority of invasive plant seed, disease and insect pests are accidentally introduced. How, you might ask? While the list of pathways is surprisingly long, the most common avenues are the movement of goods produced in foreign countries, travelers returning home with souvenirs, and internet sales. The U.S. Department of Agriculture (USDA) and Customs and Border Protection (CBP) work to prevent the introduction of such pests. In this month of increased holiday travel by both people and packages, the Maryland Invasive Species Council has chosen this prevention work as the topic for the December's "Invader of the Month".

Cargo is moved in large containers with products shrink-wrapped on pallets, in boxes, or simply loaded in trucks. This results in many small hiding places that insects, seeds, and snails can use to move, unbeknownst to them, all over the world. To prevent this from happening, CBP, a branch of the Department of Homeland Security, routinely inspects cargo. The searches are extensive and include examining the exterior of shipping containers for hitchhikers adhering to the undercarriage and walls. Inside the container, pallets are checked to ensure that they have been properly treated to prevent the movement of bark beetles and woodborers. Inspectors then move to the product being shipped. Flashlights, forceps and box-cutters are routinely used to open, inspect, and manipulate the products to ensure they are pest free. The final stage of an inspection is to sweep out the empty cargo container and look for any seeds or insects that were hiding in the corners.

Most people love escaping on vacation, but if you have ever traveled internationally you might recall filling out a declaration form before leaving the faraway airport to return home. Preventing the movement of pests in baggage is challenging and relies on several factors, including the declaration form. The declaration is a reminder to all passengers entering the US that bringing in certain items is prohibited. The declaration is a federal form and false claims are subject to penalty. To reinforce the urgency and in an attempt to keep people honest, CPB randomly selects passengers for screening, checks passenger lists against a database of previous violators, and walks the baggage floor with highly trained K9 units.

The last pathway of pest introduction is internet sales. The internet has drastically increased the average person's ability to buy products, knowingly or not, from foreign countries. Foreign markets are trying to meet the high demand for heirlooms and specialty varieties and non-GMO seeds for home gardeners. Small packets of seeds are easily mailed and are found only by hard work and highly trained K9 Units. Unfortunately, a recent study reports that our current biosecurity practices are not effectively preventing the trade of plant material via internet sales (Humair et al. 2015).

You can contribute to the economic and ecological safety of the US and your own backyard by being a careful and conscientious traveler and internet purchaser. Know what you're importing, where it comes from, and make sure it's legal.Given the sheer volume of cargo, baggage and mail entering the US on a daily basis, it is unrealistic to believe that every pest will be found. Pests such as the tomato leaf miner (Tuta absoluta), wheat bug (Nysius huttoni), oak ambrosia beetle (Platypus quercivorus) and Asiatic brown rot (Monilia polystroma) are known threats. Unfortunately there are hundreds of species like them that not only threaten our neighborhoods but the entire U.S. economy. In response to this ongoing threat, the US Department of Agriculture (USDA) has established several programs to eradicate, or at least mediate the impacts of, new pests. Examples of this work include recalling products found to be infested or in violation of federal regulations, conducting surveys in and around the ports where cargo first enters the US and pests are most likely to establish, and providing funding to perform trapping across the country for high risk pests.

For more information about Invasive Species of Concern in Maryland, visit the Maryland Invasive Species Council.

photos available electronically on request.

References

Humair, Franziska, Luc Humair, Fabian Kuhn and Christoph Kueffer. 2015. E-commerce trade in invasive plants. Conserv. Bio. (in press)

US Department of Homeland Security, U.S. Customs and Border Protection. CBP Form 6059B (04/14)

Additional Resources

Animal and Plant Health Inspection Service

The post Preventing Invaders first appeared on Maryland Invasive Species Council.

ANNAPOLIS, MD (April 1, 2015) – Exotic earthworm species in the eastern U.S. provide an additional stressor for mature and successional forests already affected by disturbance, climate change, invasive insect pests and diseases, and overabundant white-tailed deer. Where native earthworm species were extirpated due to glaciation, or in areas of permafrost farther south, exotic earthworms have colonized, even as native species repopulate these areas. Because “April showers” are likely to bring worms to the surface, MISC has chosen exotic earthworms as the April Invader of the Month.

Most of us are familiar with the long, dark reddish-brown worms commonly called nightcrawlers. Many people don’t realize that these worms are native not to the U.S., but to Europe. Exotic earthworms arrive in the U.S., primarily in soil and “plant-associated materials” in conjunction with agricultural and horticultural products. They are deliberately imported for composting, degraded soil restoration, or bait. They migrate from lake and river shores into forests when released from live bait buckets. There are over 100 species of native North American earthworms north of Mexico, and about 45 exotic species. The introductions include species from all over the world, but most of them are from Europe and Asia, due both to heavier commercial exchange with those regions, and to climatic matches between the eastern U.S. and those areas.

Although earthworms all look pretty similar – they range from under a centimeter to, in the case of giant earthworms, several meters in length. They are tubular, with a head, a long, thin body made up of segments like stacked rings, and a “tail,” more correctly called a <em>pygidium</em>. Surrounding a worm’s body, closer to the head end, is a thickened non-segmented band called a <em>clitellum</em>. The clitellum secretes a thick fluid that covers and protects fertilized eggs, which can develop in both members of a mating pair, since earthworms are hermaphroditic.

Earthworms are divided roughly into three groups depending on where in the soil they live and what they eat. <em>Epigeic</em> (“on” or “above” “earth”) worms live primarily in leaf litter on the forest floor and eat microbes. <em>Endogeic</em> (“in-earth”) worms live at or near the soil surface and eat soil in the top 4” of ground. <em>Anecic</em>worms, like the familiar nightcrawler, are burrowers, and build vertical burrows, eating litter and soil. The three types of worms, and the intermediate subcategories between them, have different pigmentation patterns and sizes.

The same behavioral effects that can make earthworms so desirable in your garden – incorporation of organic material into the soil, increases in soil porosity and water infiltration, stimulation of microorganisms that can aid plant growth – are detrimental in forests. Earthworms remove the forest duff, or leaf litter, either by eating it or by burying it. This leaves the floor more susceptible to erosion and drying out, removes food substrates for above-ground decomposers, and mixes the organic and mineral soil horizons. Changes in litter decomposition rates change with the composition of the earthworm community, and the tree species (tulip poplar leaves are easier to eat, and apparently tastier than tannins in oak leaves), but more earthworm activity means a barer forest floor.

Earthworms also eat plant seeds. For larger seeds, going through an earthworm gut may help break dormancy, or bury a seed away from its surface predators. But smaller seeds may be damaged in gut passage, or may be buried too deeply to germinate. One group of Maryland researchers found that rattlesnake plantain orchid seeds – among the smallest in our flora – were buried by earthworms deeper than the mycorrhizae they require to germinate were present. In this way, worms change the nutrient availability for orchid seeds. Earthworms decrease the abundance of mycorrhizal fungi in general, which can reduce the growth of tree seedlings that need these fungi to thrive. However, in a study in New York forests, earthworm presence did not affect the survival, growth or reproductive capacity of several forest wildflowers, but did reduce the growth of two species of forest sedges.

While research findings are somewhat contradictory, it is clear that earthworms change the amount and speed of nutrients in forest systems. Carbon, nitrogen and phosphorus flows all change in the presence of exotic earthworms, in complex and not entirely understood ways. At its most fundamental level, this results in changes in how forest plants and animals get their food.

Exotic earthworms may be in eastern forests to stay. Reducing their populations is more likely through prevention than through outright control. For example not discarding unused worms for bait in the forest. While USDA regulates earthworm importation under the Federal Plant Pest Act, the focus is on prevention of pathogens that imported worms might carry, and not the worms themselves. Various policies for limiting earthworm importation are still under discussion. Recent studies indicate that exotic earthworms and exotic plants may go hand in hand. In the southeast U.S., more exotic than native earthworms were found under invasive Chinese privet, a shrub that caused a rise in soil pH. Removal of the privet resulted in a reversion to the lower soil pHs, a decrease in exotic earthworms, and a return of native earthworms. Perhaps the best control technique for invasive exotic earthworms is NOT TO PLANT invasive exotic plants!

For more information about Invasive Species of Concern in Maryland, visit the Maryland Invasive Species Council.

photos available electronically on request.

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Zebra Mussels on Driftwood

ANNAPOLIS, MD (January 1, 2015) – Named for its distinct dark and light striped shell, the zebra mussel (Dreissena polymorpha) is a small, triangular freshwater bivalve mollusk that attaches to hard surfaces with hairs called byssus. Like many other nuisance species, zebra mussels are prolific and form dense clusters, often covering whatever surface they attach to several inches thick.

Zebra mussels have caused serious problems in the Great Lakes and other water bodies where they have invaded. They have encrusted boat hulls and outboard motors, clogged power plant cooling water intake pipes, and forced expensive changes in the way municipal drinking water supply systems operate. Zebra mussels can kill native freshwater mussels, alter aquatic food webs, and affect water chemistry. Zebra mussels can also accumulate nutrients and toxins within their bodies, which has contributed to the deaths of thousands of fish-eating birds and to blooms of harmful Mycrocystis bacteria. Maryland DNR recently completed a count of the zebra mussel population found in Maryland waters. For these reasons, zebra mussel has been chosen as Maryland Invasive Species Council’s January Invader of the Month.

The zebra mussel is a small (< 25 mm shell length) native to southern Russia and the Caspian Sea. It was first discovered in North America in June 1988, in Lake St. Clair on the Michigan-Ontario border, likely being a passenger in ballast water from a transoceanic cargo ship. Since this inadvertent introduction, zebra mussels have spread as far west as California, and now occur in at least 25 states, including Maryland. Immensely fecund, these mussels can reproduce quickly, and can be moved in water bodies and between water bodies by attaching to boats, trailers, and aquatic plants.

Unlike native bivalves, zebra mussels are dioecious spawners, releasing tens of thousands to millions of gametes in the water column when water temperature approaches 15ºC. Their larvae, called veligers, may be free swimming for up to a month before settling out of the water column. To survive, the settled mussels attach to hard substrate using byssal threads. They live attached for up to 10 years and grow about 1-2 cm per year. Zebra mussels become sexually mature their first year.

In November 2008, 20 years after showing up in North America, zebra mussels finally arrived in Maryland. A single adult mussel was found at the Conowingo Dam in the lower Susquehanna River. Less than a month later, a second mussel was found on a boat hull at Glenn Cove Marina, in Harford County, Maryland. Between 2009 and 2013, a few more zebra mussels were found scattered throughout the upper Chesapeake Bay. With fewer than 50 live and dead specimens reported, the zebra mussel population, although apparently established, did not seem to be expanding.

In the fall of 2014, however, results from monitoring a network of buoys and anchors that are located throughout the lower Susquehanna River and upper Chesapeake Bay changed the picture. On 15 anchors located in tidal-freshwater, researchers found more than 500 zebra mussels. In 2012 and 2013, those same anchors sported only 14 and 20 mussels, respectively. Not only did the numbers increase, but the distribution widened: in 2012 and 2013, all the zebra mussels found came from only three of the 15 anchors surveyed; this year, 14 of the 15 contained the invasive mollusk. Watermen who fish the Susquehanna Flats also reported mussel-encrusted gear.

There is no evidence that zebra mussels in their current numbers are causing ecological harm in the waters of Maryland where they have been found so far. They are likely causing minor economic impacts to water users who must inspect, monitor, and clean intake pipes periodically from fouling. In the coming years, recreational boaters, commercial fisherman, and marinas will likely find they must spend additional time cleaning outboards, hulls, trailers, mooring anchors, or any hard surface that is in infested waters for more than a few days.

Typical treatment methods for zebra mussels involve physical removal, chemicals, and molluscicides. A recent zebra mussel-specific product has been used with some success at eradicating them from small parts of closed bodies of water like ponds and lakes. Ways to reduce the effects of zebra mussels around local areas of value, such as water intakes or marinas, requires continuous treatment and can become expensive. Research in the 1990s in the Great Lakes region explored the use of hormones and phytoplankton-generated chemicals to disrupt the zebra mussel reproductive cycle. Currently, there is no method ofcontrolling zebra mussel populations in an open water system like the Susquehanna River or other freshwaters of the Chesapeake Bay drainage.

The spread of zebra mussels through Maryland waters can be slowed or even stopped. DNR is asking citizens to help prevent the spread of this notorious non-native species by following several simple guidelines listed on the Stop Aquatic Hitchhikers signs posted at boat ramps and marinas in zebra mussel-infested areas.

• REMOVE all visible mussels and aquatic plants from your boat hull, external drive unit, propeller, trolling plates, anchor, trailer, and fishing tackle; put debris in a trash can well away from the water body.
• DRAIN all water from live wells, bilge areas, bait buckets, SCUBA gear, and coolers.
• FLUSH engine cooling system, drive unit, live wells, bilge areas, bait buckets, and coolers with hot water, if available.
• RINSE boat hull, trailer, fishing tackle, and SCUBA gear with hot water or a hard spray from a garden hose.
• DUMP left over/unused bait in a trash can; DO NOT dump or release it live to the water body.
• DRY your boat, engine, trailer, fishing tackle, dive gear thoroughly for at least 5 days between outings—-longer if possible.

These steps could help assure your favorite body of water stays zebra mussel free.

For more information about zebra mussels, go to USGS Zebra Mussel NAS fact sheet.

For more information about Invasive Species of Concern in Maryland, visit the Maryland Invasive Species Council.

photos available electronically on request.

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ANNAPOLIS, MD (April 15, 2013) – The zebra mussel, a small freshwater mollusk native to southern Russia and the Caspian Sea, was first discovered in North America in June 1988, in Lake St. Clair. Since this inadvertent introduction, zebra mussels have spread as far west in the United States as California, and now occur in at least 25 states, including Maryland.

In November 2008, 20 years after making its debut in North America, zebra mussels finally showed up in Maryland. A single adult mussel was found at the Conowingo Dam in the lower Susquehanna River. Less than a month later, a second adult zebra mussel (dead) was found on a boat hull at Glenn Cove Marina, upstream from Conowingo Dam in Harford County, Maryland.

Since 2008, a few more zebra mussels have been found in the lower Susquehanna River, Maryland, and in upper Chesapeake Bay. However, with less than 50 live and dead specimens reported, the zebra mussel population there, although apparently established, does not seem to expanding rapidly. “So far, there is no evidence that zebra mussels are causing any ecological or economic impacts in the areas in Maryland where it’s currently found”, says Dr. Ron Klauda, a biologist with the Maryland Department of Natural Resources (DNR).

Zebra mussels have caused serious problems in the Great Lakes and other areas where they've invaded. The have encrusted boat hulls and outboard motors, clogged power plant cooling water intake pipes, and forced expensive changes in the way municipal drinking water supply systems operate. From an ecological perspective, zebra mussels can kill native freshwater mussels, including endangered species, and clams. Zebra mussels also accumulate pollutants and toxins, and have contributed to thousands of fish-eating bird deaths.

“It’s unfortunate that zebra mussels finally made it to Maryland”, says Klauda. “Although, frankly, we feel lucky that it took so long for them to get here. What we are trying to do now is keep them from spreading from the lower Susquehanna River and upper Bay to other Maryland waters that have suitable zebra mussel habitat.”

To help stop the spread, DNR is spreading the word to boaters and anglers. “We’re asking them to Stop Aquatic Hitchhikers by following several simple guidelines listed on signs that have been posted at boat ramps and marinas in zebra mussel-infested areas”, says Klauda. “I’m also asking anyone who finds what they suspect is a zebra mussel to call me at 410-260-8615. We want to know if zebra mussels are spreading and the public can help us by being alert.”

DNR staff recently compiled water quality data collected in non-tidal areas throughout out the State. Zebra mussels are freshwater mollusks, but need
non-acidic habitats with sufficient levels of calcium to survive and thrive. “As expected, there are many rivers and reservoirs in Maryland with suitable zebra mussel habitat”, remarked Klauda. “However, we were somewhat relieved to find out that Deep Creek Lake, a popular recreational area in Garret County, is probably not good habitat for zebra mussel establishment and proliferation because the calcium levels are quite low”.

For more information about zebra mussels and other Invasive Species of Concern in Maryland, go to the Maryland Invasive Species Council.

photo available electronically on request.

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ANNAPOLIS, MD (March 8, 2013) – Exotic and alien species arrive in the US daily. Whether they are brought in intentionally or accidentally makes little difference; the end result can be the same – new introduced pests with potential to cause serious impacts on agriculture, the natural environment, commerce, and human health and well being. Most alien snails (and slugs) are transported inadvertently. Most species are generalist herbivores (plant feeders). Many can act as intermediate hosts of human and livestock parasites. They can potentially negatively affect local agriculture, impact native species, and create a reservoir for further spread of the pathogens they carry. They move silently, on plants, in trucks, airplanes and ships. Their dispersal into new habitats seems to be wholly, or in part, due to human activity, and as such they can be called “travelling” species (Smith, 1989) and “tramp” species (Solem, 1964). Two gastropod tramps and travelers have been found recently in the Port of Baltimore, which is why MISC has chosen them as the March Invader of the Month.

Two species of exotic snails were recently found to be quietly enjoying the ‘Land of Pleasant Living’ in Baltimore. The heads-up on their presence was given by a West Virginia company receiving cargo originating from a maritime terminal in the Port of Baltimore. The terminal owners were promptly contacted and regulatory officials arranged to survey the area. The search target was the snail identified as Eobania vermiculata, the chocolate banded snail. Officials found the species around the holding area, buildings, on trees, and railroad tracks that terminated near the holding area. A second snail species collected during this survey turned out to be a bit more of a concern as it is ”reportable” – i.e. of quarantine signifigance to USDA. Regulators conducted another survey to assess the distribution of this newly uncovered snail – the maritime garden snail, Cernuella cisalpina and found specimens outside of the terminal holding area, along the railroad tracks, and distributed over a much larger area.

Snails are gastropods with external spiral shells that the animals can retract into completely for protection from predators and extreme weather. Eggs are small, globular structures laid in groups, usually white when newly laid, They are often difficult to identify — identification to species level is best left to trained taxonomists. Although we don’t know right now what negative impacts the newly discovered maritime garden snail would have in Baltimore, we do know that a closely related species, Cernuella virgata, sometimes also called the maritime garden snail, has been a serious problem in areas where it was introduced in Australia. The snail frequently climbs to the top of vegetation to escape high temperatures and drought conditions, which wouldn’t be a problem if it didn’t occur in large numbers on cereal crops destined for export. The contaminated crop is unfit for human and livestock consumption, causing huge losses to the farmers. The presence of large numbers of snails in harvested grain elevates the moisture content and promotes secondary infestation by fungal pathogens that produce toxins in the grain. Toxin-contaminated grain is unmarketable, as it is not fit for animal or human consumption. The snail also contaminates pastures.

Imported goods such as tiles, marble and granite slabs from around the world, particularly the Mediterranean region, are known commodities that commonly transport tramps and traveler snails.

In the past 10 years, there have been approximately 12,000 mollusk interceptions at US ports, airports and border crossings. One of the most common routes of entry for snails is on imported tiles. Since 1984, Cernuella spp. and the chocolate banded snail have been intercepted 2,722 times in the US, 55 times in Baltimore ports of entry; in 45 of these shipments were destined for sites in MD.

Cernuella cisalpina is known to be established in coastal Virginia and North Carolina. The chocolate banded snail is not an actionable pest by USDA because it is already too widely distributed in the US. This species is used as food in many countries due to its larger size. Problems associated with these alien snails include quarantine and the associated chemical applications and misery of such status. They can do real harm to nursery stock, grass seed fields, vineyards, tree fruits, small fruits, and grain crops. Worse yet, they can carry diseases and parasites detrimental to native snails and animals as well as people. The rat lung worm, Angiostrongylus cantonensis (Chen), which causes eosinophilic meningitis, a potentially lethal human disease, can be transported by snail mucus on leaves or snail meat.

The challenge now is to see what can be done with the actionable snail, the maritime garden snail. The Baltimore Port terminal took steps to eradicate the chocolate banded snail and results look promising. The maritime garden snail might be controlled or eradicated using one of the commercially available bait products. Relatively environmentally friendly products containing iron phosphate may be recommended choices.

For more information about Invasive Species of Concern in Maryland, visit the Maryland Invasive Species Council.

photos available electronically on request.

Additional information on the Web:
A Snail Tail, Oregon State University

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ANNAPOLIS, MD (September 20, 2012) – Many people have fond memories of raising some sort of classroom “pet,” be it butterflies, frogs, fish, hermit crabs, or “regular” pets like hamsters or gerbils. Watching a plant or animal go through its entire lifecycle is incredibly fascinating and can be an invaluable experience for a child who is just getting excited about learning.

But what is growing in your classroom? Are you learning about a native species, or a foreign one? And when you’re done with your classroom pet or project, what happens?

Ideally (perhaps to the surprise of some), these organisms should either be kept by students or teachers, or humanely disposed of. What many people don’t realize is that many of the species grown in classrooms, while great for education, are bad for our Maryland ecosystem. If the species does not occur naturally, and it proliferates in the wild (as so many do), it can do great harm to the naturally occurring flora and fauna. These organisms pose special risks because the people caring for them (simply by being students and their teachers) are often not as knowledgeable about the organisms as they could be, and not prepared for the long term (i.e., the organism’s lifespan). Release into the wild after a stint in a classroom is all too common. For this reason, classroom organisms have been chosen as the Invader of the Month.

If you were to think about the pets one might raise in a classroom, what comes to mind? Butterflies are probably your first thought. Many a class has raised a caterpillar and watched it turn into a chrysalis and then a beautiful butterfly when learning about the life cycle.

In Maryland, we of course have lots of beautiful native butterflies. In fact, our state insect is the Baltimore Checker-Spot butterfly. Unfortunately this species of Maryland fauna is now fairly rare. Other natives include the monarch, the red admiral, many types of swallowtails, etc. In classroom projects, the most common butterfly to raise is the Painted Lady. This is also a native species, and is an example of something that could be safe to release into the wild. But butterflies like the Cabbage White, originally from Europe, are actually invasive, and should be avoided.

Goldfish are another common classroom pet (and are also something commonly won at fairs, by children). Those who do not want to care for them often release them into backyard ponds, lakes, and streams, where they usually thrive, as goldfish are a hardy, coldwater species of carp. We have carp here—but not this kind! Goldfish can grow to extremely large sizes given space and food. In fact, outgrowing a tank is often the reason people release them. Given a wide open pond with plenty of smaller things to eat, they can quickly take over.

Frogs are another example of this idea; if you get tadpoles, children can watch the frog slowly but surely come into its own and reach adulthood. It’s natural, after that, to want to release it and allow it to thrive as an adult. But know what you grow; non-native frogs are incredibly dangerous to an ecosystem. Imagine if someone were to release African Clawed frogs (common in gift stores) into a stream or lake—this particular frog can grow to 5 inches and is voraciously carnivorous.

You might be surprised by the kind of animals you could find in classrooms, too. I know a girl who has a pet tarantula that used to be a class pet—no tarantulas are native to Maryland, so this was the perfect “final destination” for that arachnid. People also keep stickbugs, which are awesome classroom pets, but many species of them are also parthenogenic, and could be absolutely devastating to an ecosystem if not properly contained. Even the waste from these insects has to be properly disposed of, because it could contain eggs (freeze it for a few days before throwing it out).

It’s not only animals from classrooms that can be a problem, of course. Plants are some of the worst invaders. They can spread with alarming rapidity, especially water plants. Plants such as the anacharis (elodea)-like hydrilla are popular in classrooms to use under the microscope, because they have such easily seen cells in their leaves. They are also popular in aquariums; so put your plants to use there after you’re done in the classroom, instead of in the wild! Anyone that has had anacharis in their aquarium knows how fast it can grow. Anacharis is native to North America, but hydrilla is not, and many lakes across the country are having huge problems with the spread of this water weed.

Perhaps one of the coolest, and most dangerous, classroom projects is a mini ecosystem, or terrarium. Often these have multiple organisms in them—snails on the land portion, a goldfish or guppy in the water, an aquatic plant for the fish, etc, a perfect storm. I’ve already mentioned the dangers of invasive fish and plants.

Gerbils are an active, social and interesting classroom pet. They are omnivorous, hardy and are perfect invaders. In fact, California bans possession of gerbils for fear that they would establish themselves in agricultural fields.

Keep, don’t release! Whether it’s something you acquired from school or the fair, keep it or rehome it, but don’t release it into the wild. Past science projects can make fascinating pets. If you can’t keep it, humanely dispose of it rather than release it. It’s better than disrupting our Maryland ecosystem. Most plants and insects can be safely and easily disposed of by freezing. Or you can find someone who would appreciate a new pet to care for and love. But whatever you do, don’t release non-native species into Maryland’s ecosystem. It’s not doing anyone (or anything) any favors.

For more information about Invasive Species of Concern in Maryland, visit the Maryland Invasive Species Council.

photos available electronically on request.

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ANNAPOLIS, MD (July 11, 2012) – Summer is here and it is time to dust off that kayak, pull the waders out of that closet, put a new coat of wax on that boat, inflate the tires on that trailer, and string up some new line on that fishing reel! New adventures await you on Chesapeake Bay and in Maryland’s beautiful streams, rivers, and lakes. As you set out on your summer excursions, keep in mind that your actions, or inaction, can cause irreversible damage to the very ecosystems you enjoy. The things that you use, be it your waders, wading boots, kayak, canoe, boat motor, boat trailer, and even your mask and snorkel may harbor invasive species and contribute to their spread. Zebra mussel, quagga mussel, Didymo, and chytrid fungus are just a few of the harmful species that have been inadvertently spread throughout many regions of the U.S. by outdoor enthusiasts, including kayakers, canoeists, anglers, boaters, and divers. Stopping the spread of these species in Maryland requires your vigilance! With the summer of 2012 here, the Maryland Invasive Species Council has chosen “Clean your Gear” as the July 2012 Invader of the Month.

Recreational gear can become a vehicle on which invasive species can be carried from one water body to another. For example, the Zebra mussel (Dreissena polymorpha) is an invasive mollusk native to Eurasia that was first introduced into the Great Lakes in 1986. Since then, this species has been introduced throughout much of North America, spread primarily by recreational boaters. Zebra mussels have “hitchhiked” great distances attached to boat hauls, props, or motors, or hidden in live wells, coolers, and bait buckets. Recreational boaters trailering their boats from one water body to the next can inadvertently spread zebra mussels and other “hitchhiking” organisms. Invaded areas have suffered ecologically. Zebra mussels have drastically altered aquatic food webs and have been linked to declines in commercially important fisheries. The economic impacts of zebra mussel invasions have been huge. Biofouling by zebra mussels of municipal and industrial water pipes and infrastructure require millions annually to treat. Zebra mussels and other aquatic hitchhikers cost us all a lot of money! In Maryland, zebra mussels are known from the Lower Susquehanna and Sassafras rivers. The threat looms large that this invasive species may invade other Maryland rivers, lakes, and reservoirs with the aid of boaters unaware of the issue.

Zebra mussels, invasive aquatic plants, and other large organisms attached to boat hauls, props, or trailers are usually easy to detect and remove. But, not all hitchhiking species are obvious. Many are not easy to see, even if you are looking for them. Microscopic algae, pathogens, or larvae can remain hidden in your recreational gear and can also be transferred from one water body to the next if you are not careful and thoroughly clean your gear between water bodies and outings.

Didymo (Didymosphenia geminata), commonly called “rock snot” or “boulder boogers”, is a species of freshwater diatom native to cold regions of North America, northern Europe and Asia. In recent years, Didymo has expanded outside of its native range and has become a nuisance species in many prized trout streams. Didymo attaches to submerged surfaces in streams and can form thick mats, smothering important habitats for stream insects and other bottom-dwellers. These “blooms” can reduce the food sources of game fishes. It is believed that anglers have unwittingly spread Didmyo, carrying it from one water body to another in or on their boots and fishing gear. Even a single cell of Didymo attached to a pair of chest waders or hidden under a boot lace can contaminate a new water body. Didymo was first discovered in Maryland in 2008 in the Gunpowder River. It is now known to also occur in the Savage River and portions of Big Hunting Creek. In recognition of the threat posed by Didymo and the role that waders and wading boots have had in the spread of this invasive species, the Maryland Department of Natural Resources banned the use of felt-soled wading boots in March 2011.

Didymo is not the only tiny invasive species that is a big threat to Maryland’s aquatic ecosystems. Chytrid fungus and ranavirus are infectious agents that have decimated populations of amphibians and reptiles in many parts of the world, including Maryland. These tiny pathogens can also be spread on contaminated recreational gear.

Protection of our waters from invasive species requires an informed and vigilant community of anglers, boaters, canoeists, kayakers, divers, and other outdoor enthusiasts here in Maryland. Your actions can make all the difference.

You can help prevent the spread of invasive species by cleaning all of your recreational gear after each trip. There are several ways to decontaminate your gear so that you do not move invasive species around. To protect our waters, always:

• Remove all vegetation and organic matter from your gear
• Drain all water from live wells, canoes, and kayaks
• Clean your gear with a 10% bleach solution. Be sure to use bleach and other cleaning agents away from waterways to reduce potential harm to non-target animals
• Let your gear dry for at least 48 hours (preferably longer) between trips

And most importantly, spread this message to other Marylanders! Give them this information and tell them to pass it on!

For more information on cleaning your gear, Didymo, and other invasive species visit these links:

Maryland Invasive Species Resource Center, Maryland Department of Natural Resources

Decontamination, Maryland Department of Natural Resources

JUST SAY “NO!” TO DIDYMO, Maryland Department of Natural Resources

For more information about Invasive Species of Concern in Maryland, visit the Maryland Invasive Species Council.

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