Monthly Archives: September 2015

Ranavirus, Amphibians, and How to Keep them Apart



Sometimes naturalists take precautionary steps just so they can do their job. Sometimes your help is needed to protect wildlife.

This past spring, May 2015, Old Colchester Park and Preserve experienced a wood frog tadpole die-off. Tadpole samples were submitted to the U.S. Geological Survey’s National Wildlife Health Center, which led to a positive test result for a strain of ranavirus.  This followed a 2014 Smithsonian study that returned an “unconfirmed positive” result for the same population of frogs.  Arlington County Parks Natural Resources Manager Alonso Abugattas noted that an Arlington park had an unconfirmed positive, and other parks in Northern Virginia that were part of the 2014 Smithsonian study also returned an “unconfirmed positive result.”

Ranavirus is a disease that affects amphibians, reptiles and fish.   It has never been known to infect humans.  The virus varies greatly in lethality, infection rate and symptoms.  Frog tadpoles, for example, show blood and lesions on the belly and around the hind limb buds and are usually only symptomatic during their development when hind limb buds are forming.  It is possible and likely that the virus has been present in our area for many years, but relatively little monitoring has been done in Northern Virginia.

With the confirmation of the virus at Old Colchester, naturalists from the Fairfax County Park Authority notified other area naturalists of the test results and urged them to take whatever precautions they could to protect wildlife in their parks and across the region. Amphibian populations or susceptible rare animals, such as wood turtles, could be affected by the disease, and there is no cure or direct treatment for it. In addition, parks with a lot of foot traffic in amphibian habitat could see their amphibian populations affected. To that end, FCPA recommended that school groups and citizen science workers also take precautions.

What are those precautions? The best action is prevention. That means halting the spread of the disease, and that means disinfecting boots, nets, containers and other gear before entering parks, vernal pools and ponds. That one step is the standard procedure for preventing the spread of ranavirus. Signs and publications, like this blog, also help make residents good stewards of nature.

Abugattas said Arlington County is taking precautions that include water sampling and macroinvertebrate surveys, noting that surveyers should follow proper disinfection protocols before moving to a new sampling site. Trained naturalists and support groups can help by monitoring wildlife population trends and watching for, what the professionals call, a “mortality event.” That’s generally considered five or more dead animals within the same population.

So scrub your boots, keep an eye on the environment, and report anything amiss to park staff.

More information is available from the Virginia Department of Game and Inland Fisheries. (


Author Owen Williams is a Natural Resource Specialist for the Resource Management Division of the Fairfax County Park Authority.

Farmers Markets Celebrate Successful National Farmers Market Week

basketNational Farmers Market Week is a celebration acknowledging our local farmers who ultimately are responsible for bringing fresh ingredients into our homes. The 2015 Fairfax County celebration which just concluded included lots of activities for families. An environmental education booth provided extensive information on the ways our market vendors help restore and protect the environment and their farmland. At each market a gift basket including vendor products, coupons, an Arcadia seasonal cookbook and a reusable tote was offered as a door prize. Recipients were thrilled and looking to return to market for more.

20688560416_ba83d35a48_kChildren enjoyed hula hoops and sidewalk chalk at each market, and they left the pavement decorated with multi-colored fruits, vegetables, and jumbled scribbles. The Virginia Cooperative Extension’s Master Food volunteers delighted kids and adults alike with a food quiz wheel. After answering a trivia question correctly, winners were offered stickers and recipes for cooking fresh produce. At the Herndon market, children gathered for a watermelon seed spitting competition. With fresh watermelons from vendor Mount Olympus, a volunteer gave each of the kids a watermelon slice and carefully marked the farthest ejected seed.

A cooking demo by Virginia Cooperative Extension’s intern Miriam Eackloff filled the market with mouth-watering aromas. One recipe featured cheesy kale and brown rice, a healthy and inexpensive item using seasonal ingredients. Her French toast with peach sauce was the perfect recipe for early morning market attendees. The free samples she offered disappeared in no time.

MarketVendors were especially pleased with the increased foot traffic and festive atmosphere at each market. Bob Baldwin, Market Master at McLean, said National Farmers Market week brought the market some “new energy” in an educational and fun way.

At the Farmers Market Week tent, customers completed a quick seven question survey to win a free “Buy Fresh Buy Local” reusable shopping bag. These surveys will provide valuable information that the Fairfax County Park Authority will use to improve the quality of all 11 markets. National Farmers Market Week at the FCPA Farmers Markets was a local success! Whether you are a seasoned market attendee or a newcomer, the market always offers a little something for everyone.


Author Emma Hansen is the Farmers Market Program Assistant. She is based at Green Spring Gardens, which coordinates 11 markets in the Fairfax County Farmers Market system. Please visit or call 703-642-0128 for more information

Lake Accotink Dam Fish Kill

Lake Acotink DamThis starts with an email from a park visitor.

On a recent Saturday evening, a park patron sent us a note telling us that she and other visitors were concerned about dead fish they saw below the dam at Lake Accotink. It appeared that the fish had been trapped after water receded and left them stranded behind rocks.

The patron’s email expressed concern over the oxygen level in the pool, the health of the fish, and the possibility of dying fish attracting other wildlife to the spot, which is near a paved hiking trail.

At first glance, it sounded like a naturally occurring event, the whims of nature. But that wasn’t the issue, and the visitor’s email proved to be quite valuable. It brought forward a problem apparently caused by another visitor to the park.

Usually, water flows out of the basin below the dam and runs through a culvert under the paved hiking trail. But that wasn’t happening.

Lake Accotink Park Manager Julie Tahan explained: “Someone had placed rocks in the sluiceway last week, blocking it enough to prevent water from flowing through the sluiceway. The blockage caused the water level in the stilling basin to rise, which created an inviting pool on the upstream side of the triple culvert under the trail. Fish congregated there, which is what we think may have been the motivation for whomever blocked the sluiceway.”

In a rainstorm the improperly moved rocks will cause the water below the dam to flow over the trail, which hampers trail use and is at least an inconvenience if not an endangerment to hikers and bikers. In addition, moving the rocks is a violation of park regulations, and the trapping of fish in this manner is a breach of outdoor sportsman ethics.

Staff had to spend time removing the rocks, which brought the stilling basin back to its normal level but also caused the pool of water harboring fish to recede. The fish were trapped in turbid water and likely succumbed to low oxygen. Tahan says an attempt to save the fish would have had limited success because of the labor involved, the small size of the fish, and the difficulty of netting them in the rocky, murky pool.

This has happened in previous years, and Tahan says that it’s happening again more frequently. She added, “On Saturday – the day after staff removed all the rocks — a patron reported seeing a man placing rocks at the dam. He was gone when we went to check it out.”

Staff from the Virginia Department of Environmental Quality (VDEQ) corroborated what the Park Authority found and said there is not much that can be done to prevent it. VDEQ ruled out chemical or hazardous spills as a cause of the fish kill, agreeing that the fish died from lack of oxygen.

“Knowing that Accotink Creek is in a highly impaired watershed, any aquatic life that does live in its waters is already challenged to survive,” Tahan said. “Additional stress on their habitat can easily have a detrimental impact.”

By Monday, fish that survived had made their way into the deeper waters of the creek that drains the lake, and the eagles, herons, and other birds that include fish in their diets were removing those that did not survive.

Tahan noted that this can be visually unappealing to human sensibilities, however the Park Authority does not try to control every aspect of nature, especially a temporary one like this. Any birds or snakes feeding in the area already are common in the park and are being good stewards of nature.

The Park Authority is considering steps to solve the rock-moving problem. Patrolling the area eats into valuable staff time, and posting cameras as monitors has been suggested but has costs. One other possibility is to ban fishing at the stilling basin. Tahan says that allowing folks to fish there may tempt them to move the rocks, and a ban on fishing at the spot would alleviate a longstanding situation of fishermen setting up in the path of bikers and walkers using the trail. There would still be plenty of fishing opportunity along the creek and in the lake itself.

Notifying the Park Authority of the trapped fish was the right thing for the park visitor to do and is something we encourage when a visitor sees something they feel is amiss in a park. It shows care and concern for nature, for parks and for a healthy environment. At Lake Accotink, the number to call to notify staff of improper activity is 703-569-3464.