Did you have a pet Red-Eared Slider Turtle (Trachemys scripta elegans) when you were growing up? The distinctive red stripe on the side of the head is attractive and makes it easy to identify them.

The red-eared slider turtle is native in much of the mid- to south-central United States. However, it is an invasive species in California, Oregon, Washington and many other states. The US Geological Survey has mapped areas where it is native and not. Click this link and then scroll down to see the map.

California Department of Fish and Wildlife’s (CDFW’s) Outdoor California magazine reports that non-native pet turtles, like the red-eared slider, are a threat to California’s only native freshwater turtle, the Western Pond Turtle (Emys marmorata). Sliders became a problem because so many owners set them free in a local pond or lake. CDFW recommends removing red-eared slider turtles and other non-native species, like bullfrogs, that eat or compete with native species. They also recommend leaving native western pond turtles in peace. (Be patient if you click on the Outdoor California link; the file downloads slowly because it has lots of information and great photos.)

Why are red-eared sliders such a threat? Oregon Department of Fish and Wildlife reports that they compete with native turtles for food, nesting and basking space, and hiding places. Native turtles have no immunity to parasites and diseases carried by red-eared sliders. Turtles can live more than 20 years, so if you set them free, they will pose a threat for a long time! Dhi (see photo below) has been a pet for 18 years. Her human family decided to keep her, instead of releasing her to a local pond.

Columbia University explains that the red-eared slider plays important roles as both predator and prey in its native range. Because they are aggressive and bold, they compete for both food and space with native turtles, where they are introduced.

Buyer Beware! Small turtles sold as pets also cause Salmonella infections in humans. In May 2013 the federal Centers for Disease Control and Prevention reported a salmonella outbreak that affected 391 people in 40 states and the District of Columbia. 70% of the sick people had been exposed to turtles, and 89% of these people had been exposed to small turtles (shell less than 4 inches long). 30% of sick people with small turtles had bought them from a street vendor and 13% had bought them from a pet store. The CDC notes that in 1975 the US Food and Drug Administration banned sales and distribution of turtles less than 4 inches long, so it’s surprising that they are still being sold.

To download a red-eared slider coloring sheet you can print for kids, click on the link at the bottom of this post.

UC Cooperative Extension Advisors Leigh Johnson, Sabrina Drill and Darren Haver trained 181 employees of public works, parks and a UC Research and Extension Center in Spring 2013 to recognize, report and decontaminate their field gear to avoid spreading aquatic invasive species.

This icky sounding aquatic invader threatens tourism, fisheries and even hydropower facilities that depend on our streams and rivers. Why?

Rock snot, aka didymo (Didymosphaenia geminata), is a one-celled alga or diatom. Each tiny didymo grows a gelatin-like stalk it uses to attach itself to rocks, plants and just about any available surface under the water. Didymos reproduce by dividing and so do their stalks, eventually creating a branching network that feels like wet cotton or wool. Thus, the problem...

Didymo can “bloom” (grow to very large numbers) and accumulate in large globs that look slimy, hence the name “rock snot.” Check out the USDA National Invasive Species Information Center for a video of a New Zealand stream with masses of blooming didymo.

Blankets of didymo can reach 8 inches thick, smothering mayflies, stoneflies, caddisflies and other native, bottom-dwelling aquatic life that are food for fish and birds. Didymo mats also foul spawning grounds for salmon and trout and interfere with water flow. Pennsylvania’s “Aquatic Invasive Species (AIS) Action Plan: Didymo” has a nice summary of didymo’s natural history and the harm it causes.

In California, didymo is found in the Sierra Nevada mountains, the north-central part of the state, and the south fork of the American River. Scientists thought for many years that didymo lived only in clean, cold-water streams and rivers. New research has found that it can tolerate water as warm as 80^∘ F and it grows faster when nitrogen and/or phosphorus levels rise. This means that didymo is also a threat to streams and rivers at lower elevations and in warmer climates.

How does didymo spread to new streams and rivers? Like many aquatic invaders, didymo hitches a ride with people. It can survive at least 40 days in cool, damp and dark conditions. So, didymo spreads easily on fishing tackle, neoprene waders and wetsuits, compartments on boats and other gear, felt soles of wading boots, clothing and even the family dog.

What can you do to avoid spreading didymo to new streams and rivers? Start with the slogan, Check, Clean, Dry! In other words, before you leave a site, CHECK your gear, clothing, the dog’s feet, truck tires if you forded the stream, etc. for obvious (and hidden) clumps of algae and leave them there. If you find any algae globs later, dry them and soak them in bleach for at least 4 hours. CLEAN your gear, waders, etc. by soaking and scrubbing for at least 1 minute in hot water, 2% bleach solution, antiseptic hand cleaner or dish detergent. Such cleaning is not practical for livestock and pets. So, let them (and your scrubbed gear) DRY completely and then wait another 48 hours before allowing them to contact or enter any other waterway.

For detailed decontamination protocols, visit Biosecurity New Zealand’s didymo pages.

Anglers, boaters and people who work in and around rivers and streams can be an early warning system for didymo both in cold-water streams and rivers, as well as in warmer and more polluted waterways. If you think you have seen didymo or “rock snot” report it to CA Department of Fish and Wildlife. See our “Rat on Aquatic Invaders” blog for instructions on how to report sightings of aquatic invasive species.

Scientists, fly-fishers, tribal agencies, conservation groups and others met in 2006 to document the problems didymo was causing and recommend action. The excellent White Paper they published in January 2007, a map of didymo locations, and a rough guide for field identification are available from US EPA Region 8. 

UC Cooperative Extension Advisors Leigh Johnson, Sabrina Drill and Darren Haver trained 181 southern California public works, parks and UC research staff in Spring 2013 to recognize, report and decontaminate aquatic invasive species, including didymo or “rock snot.”

Who ya gonna call? If you spot a suspected aquatic invader, where you report it depends on the critter or weed.

Remember to take photos with a camera or, even better, geo-tag them with a smartphone. Take a snapshot that shows just where you saw the invasive species, such as a streambed, lake or pond. Next, photograph the whole animal or plant and then add close-ups of distinctive features. For example, check mussels for “byssal” threads that attach them to surfaces and photograph them. If it’s a waterweed, add close-ups of leaves, flowers, roots, etc. Handle shellfish and plants carefully. AVOID picking up or getting close to crayfish, snapping turtles, clawed frogs, snakes or others that may be able to bite or scratch you!

If it’s an animal (mussel, clam, snail, crayfish, crab, fish, frog, snake, turtle, etc.) or a marine plant (such as the brownish Asian kelp that's also called wakame, or the little bright-green feathers called Caulerpa taxifolia), contact California Department of Fish and Wildlife’s (CDFW’s) invasive species hotline. You can reach them at (866) 440-9530. The message says it is the quagga and zebra mussel hotline, but they also handle other invasive animals and marine plants. Or, you can email them at invasives@dfg.ca.gov

Visit the CDFW online for their Invasive Species Report Form that you can fill out on your computer. Either print the form and send it with pictures or samples to the address on the form. Or, “print” the completed form as a .pdf file and email it to the above address along with e-photos. And, because dead creatures and seaweeds rot quickly, pictures may be the better way to go!

You will need to tell CDFW the name (if you know it) of the suspected invader and whether it is a plant, shellfish, snake, fish, frog, etc. Next, describe its size, color, shape and other distinctive features. Give the date and the California county where it was sighted, plus directions to the location where you saw it. (If you have geo-coordinates, give them, too.) Give the name of the land owner or manager, for example “John Doe” or CA Department of Parks and Recreation.

CDFW may need to contact you for more information, so they also ask for the first and last names and contact information of the person who sighted the suspected invasive species.

If the suspected invader is a waterweed, report sightings to the Agricultural Commissioner’s Department in your local county government. A list of county Ag Departments is available from California Department of Food and Agriculture First, click your county on the map. Look for your local Ag Department’s address and a phone number to call for instructions on how to submit a report and a sample. If you can get there quickly, you may be able to bag, tag, chill and deliver a waterweed specimen before it rots. Otherwise, spread out the waterweed, place it between sheets of absorbent paper and add a weight, so it will dry flat. Change the paper often, until the sample is completely dry.

Cooperative Extension Advisors Leigh Johnson, Sabrina Drill and Darren Haver trained 181 staff of public agencies and a UC research center in a Spring 2013 workshop series on how to recognize, report and decontaminate their gear to avoid spreading suspected aquatic invasive species.

How can boaters, anglers, and anyone else who works or plays in wet places help stop aquatic invasive species from conquering new territory? Decon (decontamination) is critical. Invaders can hide in mud on the tread of your boots, cling to the hem of your pants, lurk in damp reels and creels, hang out in bait wells and bilges, yatta yatta! They’re experts at surviving, so you can carry them to the next spot.

What’s the first step in decon? Just take a look! In other words, carefully inspect for mud, weeds, seeds, eggs, animals, shells, slime, etc. that may harbor (or be) invaders.

Next, scrub a dub! Scrubbing and washing boots and gear BEFORE LEAVING the site will cut risks of moving them to a new place. If you have to leave the site without scrubbing gear and boots, seal them into a heavy plastic bag or other secure container. When you arrive home or back to your headquarters, scrub and wash them where the wash-waters cannot run into a storm drain, creek, pond, lake, etc. Wear gloves and eye protection. Use a stiff-bristled brush to remove all visible traces of mud and aquatic life. Pay special attention to crevices. Seal debris that you remove into bags and dispose them in trash containers that will go the landfill.

After scrubbing, allow boots and gear to dry completely, preferably in the sun. Clothing may be put into a clothes dryer for 30 minutes on “high.” Or freeze your boots and gear for 8 hours before using them again. If you want to use the clothes dryer or freeze items, be sure it will not damage them! If you plan to visit another site before you have time to completely dry or freeze your scrubbed gear, consider having two sets and take turns using them. Either way, it’s best to visit just one site in a day.

People who use boats for work should use a boat only at a particular site. If this is not possible, then inspect and decontaminate the boat and allow it to dry completely (including bilges, wells, etc.) before visiting the next site.

Boats need extra care, because they have so many places for aquatic invaders to lurk. CA Dept. of Fish & Wildlife has a handy “Boat Cleaning Guide Book” that shows how to inspect and clean your boat to get rid of aquatic invasive species. CA Dept. of Parks & Recreation’s Division of Boating & Waterways has a great diagram showing where to look for invaders on your boat.

Check out the 100^th Meridian Initiative guidelines for drying boats contaminated with quagga or zebra mussels. These guidelines also apply to other invasive species you need to let die before putting your boat or gear back in the water.

The information in this article was presented in workshops conducted by UC Cooperative Extension Advisors Leigh Johnson, Sabrina Drill and Darren Haver and Staff Research Associate Michelle Lande for 180 employees of Public Works, Watersheds, Flood Control, Public Utilities and Parks departments in San Diego, Orange, Los Angeles and Ventura Counties California during Spring 2013. It can be used by anyone who works or plays in lakes, wetlands, watersheds, creeks, streams, etc.