Don't Let It Loose! - Mystery Snail

Don’t Let It Loose! –

Mystery snail, trapdoor snail, Cipangopaludina chinensis malleata

Where does the species originate from?

Mystery snails’ native distribution ranges from southeast Asia to Japan and eastern Russia.

How they are introduced and spread?

Mystery snails are introduced to the wild when aquariums are dumped, ornamental ponds are flooded or bait buckets are emptied. In some places it may be sold (often illegally) in both the live food trade and the aquarium/ornamental pond trade.

Environmental impact:

Impacts are unknown although large populations have been discovered in ponds, sloughs, etc. It is thought that they can compete with native snails. They are potential vectors for the transmission of parasites and diseases. In large numbers, their shells can clog water intake screens.

Snail facts:

·       The name mystery snail originates from the way these snails reproduce. Females are live-bearers  giving birth to crawling young, so to anyone observing this it appears the baby snails are mysteriously appearing out from under the mother snails shell.

·       Mystery snails have a trapdoor or operculum at the mouth of their shell that protects the snail against predators, pollutants, and desiccation (drying out).

·       Mystery snails can grow up to 2.5 inches and live up to 5 years.

Don’t Let It Loose!  Never release aquarium plants or animals into a natural water body, whether it is a small local pond, lake, or nearby river.

Submitted by Briita Orwick, Aquatic Invasive Species Intern, Region 1

Don't Let It Loose! - Goldfish

Don’t Let It Loose! - Goldfish, Carassius auratus

Where does the species originate from?

Nope, not the pet store.  Goldfish are native to eastern and central Asia, and were originally bred from Prussian carp (Carassius auratus gibelio) more than a thousand years ago.  Centuries of selective breeding has created all of the wacky color and body shapes that can be found in fish bowls around the globe.

How are they introduced and spread?

Goldfish have been farmed for live bait, intentionally stocked as forage fish, and sold world-wide for display in outdoor ponds, water gardens, and aquariums.  Goldfish are often purchased as pets then released into the wild or flushed down a toilet when owners can no longer care for them. 

Environmental impact:

Goldfish are very greedy, opportunistic eaters.  In the wild, goldfish consume everything from plants to aquatic insects, small snails and crustaceans.  The rooting and foraging behavior of goldfish can increase water turbidity and reduce the abundance of aquatic vegetation.  Goldfish may displace or outcompete native species for common food resources, introduce disease to native fish populations (goldfish ulcer disease), and can successfully hybridize with common carp – another problematic fish species.

Goldfish facts:

·       A group of goldfish is known as a “troubling”.

·       Goldfish can tan in the sun just like humans.

·       Goldfish have a memory-span of at least three months and can differentiate shapes, colors and sounds.

Don’t Let It Loose!  Those beautiful bright colors that goldfish are so famous for make them very conspicuous and more susceptible to predation in the wild – not a very fond farewell for your fishy friend! 

Submitted by Jen Poirier

Don’t Let It Loose! - Louisiana red swamp crayfish

Don’t Let It Loose! - Louisiana red swamp crayfish, Procambarus clarkia

Where does the species originate from?

Louisiana red swamp crayfish are native to the Gulf Coast and Mississippi River basin.

How are they introduced and spread?

This species of crayfish make up the vast majority of crayfish consumed as food worldwide. They are commonly sold as pets or as scientific specimen for use in classrooms for educational purposes. Sometimes they are used as live bait. Any of these uses can act as pathways of introduction if people accidentally or intentionally release them into the wild.

Environmental impact:

They feed on aquatic plants, snails, insects and fish and amphibian eggs and young, thus competing with native crayfish that eat the same food types. Red swamp crayfish are highly aggressive and outcompete native crayfish for refuge sites, thus leaving native crayfish exposed to increased predation threats. They are found to reduce amphibian populations in California through direct predation as well as competition for habitat. Invasive populations have also led to declines in native crayfish species in Europe through competition and because they often carry a detrimental crayfish fungus.

Crayfish facts:

·       Red swamp crayfish are immune to newt skin toxins, but native signal crayfish are not.

·       Crayfish usually eat their old exoskeleton (after molting) to recover the minerals contained in  it.

·       Crayfish can live 20 to 30 years.

Don’t Let It Loose!  Releasing classroom pets into the wild is bad for the pet and bad for the environment. Instead of releasing red swamp crayfish into the wild after classroom lessons are complete, some students have enjoyed celebrating the beginning of summer break with a crayfish boil. These crayfish, although a threat to native ecosystems where they invade, are not a threat to your belly. Bon appétit!

Submitted by Briita Orwick, Aquatic Invasive Species Intern - USFWS Pacific Region

Don't Let It Loose! - Part II

Don’t Let It Loose!  Seven Species Now on the Loose.

A common pathway for the introduction and spread of aquatic nuisance species is through aquarium and classroom pet/science project releases.  About a third of all aquatic nuisance species that currently threaten aquatic ecosystems are a result of the aquarium and ornamental species trade.  In addition, one out of every four educators (2,000 total surveyed) released live classroom organisms into the wild.

Can you identify seven common species introduced through these pathways?

Submitted by Donna Allard

Don't Let It Loose!

What do Eurasian water-milfoil, American bullfrog and Oriental weatherfish have in common?  That’s correct; they are all considered aquatic nuisance species in the Pacific Northwest.  What I bet you didn’t know is that all of these species have been introduced or spread by people dumping personal aquariums or releasing pets into local water bodies.  It may seem like the most humane thing to do, but releasing your pet in the wild can have many unforeseen consequences – not to mention it’s downright cruel. 

            In the next few days, we will introduce you to a number of invasive critters that have been introduced through aquarium dumping or intentional release.  If you ever find yourself in a dilemma wondering what to do with your non-native animals or plants, play it safe and just remember - “Don’t Let It Loose”!  It’s not worth the environmental harm and economic cost associated with the introduction and spread of aquatic nuisance species. 

THE DILEMMA:  Five years ago you bought a Red-eared Slider from your local pet store. Now your turtle is getting too big for his tank and you are tired of taking care of him anyway. What should you do?

Don’t Let It Loose! – Never release aquarium plants or animals into a natural water body, whether it is a small local pond, lake, or nearby river.

What kinds of critters are we talking about here?

·       Fish (aquarium fish, live bait)

·       Aquatic plants (e.g., hydrilla, Eurasian milfoil, Brazilian elodea, parrotfeather, caulerpa)

·       Crayfish

·       Snail

·       Salamanders

·       Turtles

·       Frogs

·       Crabs

·       Worms

·       Aquatic insects

THE DILEMMA:  Your aquarium is no longer functioning.  What should you do with the fish and aquatic plants in your tank?

Don’t Let It Loose! – Don’t even dump it down the toilet.  It’s not good for your plumbing and the contents may still find their way into a body of water.

What are the facts?

·       Aquarium releases are one of the top five pathways of aquatic nuisance species introductions (Ruiz et al., 1997).

·       Aquarium releases are the second largest source of introduced fish in the United States (Padilla & Williams, 2004).

·       Approximately 1/3 of aquatic nuisance species that currently threaten aquatic ecosystems originate from the aquarium and ornamental species trade (Padilla & Williams, 2004).

·       A survey of 2,000 teachers from the United States and Canada found that one out of four educators released live organisms into the wild after they were done using them in the classroom (OSU, 2012)

THE DILEMMA: Your class has been studying the crayfish life cycle for the last few months.  Now that the lesson is over, what should be done with the live crayfish that were ordered online through a biological supply company?

Don’t Let It them Loose! – Even if they can be found in the local area.

Why Not?

·       It’s cruel.  Your pet may slowly starve to death or become a tasty meal for a predator.

·       If it does survive, your pet may displace native populations.

·       Your pet may compete with native species for limited food resources or prey directly on native species.

·       Your pet may introduce harmful pathogens or parasites to native populations.

·       Over time your pet could establish a new population and become an invasive species.

·       In many states it is illegal!  

NOTE: Dumping non-native plants and pets into state waters is prohibited in Oregon and Washington.

THE DILEMMA:  You move into a new house with a large water garden that is completely overrun with aquatic plants.  You pull most of the plants out by hand and wonder the best way to discard of the unwanted vegetation.

Don’t Let It Loose! – Take care to plant native species in backyard ponds and water gardens.

What should I do instead?

·       Educate yourself about the needs of a particular species before buying.  How big will that fish grow, how long will that turtle live, how much care does a water garden need?

·       Give unwanted pets/plants to a responsible family member or friend.

·       Donate your pet/plants to a local library, nursing home, community center, aquarium club, or school biology department.

·       Contact the biological supply company, pet store, or aquarium shop dealer about returning your pet/plants.

·       Freeze aquatic plants 24 hours and discard in the trash (not the compost bin), or seal plants in a plastic bag and place in the trash.

·       Pour aquarium water on dry land instead of a storm drain, sink or toilet.

·       Ask your educational institution to not raise or use live animals in the classroom unless permanent homes can be found for them ahead of time.

·       If all else fails, contact your local veterinarian for humane disposal options.

References

Oregon State University.  “New Pathway for invasive species – science teachers”.  ScienceDaily, 7 Aug. 2012.  Web. 3 May 2013.

Padilla, D. K. and S. L. Williams.  2004.  Beyond ballast water: aquarium and ornamental trades as sources of invasive species in aquatic ecosystems.  Frontiers in Ecology and the Environment.  2: 131-138.

Ruiz, G. M., J. T. Carlton, E. D. Grosholz, and A. H. Hines.  1997.  Global Invasions of marine and estuarine habitats by non-indigenous species: mechanisms, extent and consequences.  Amer. Zool. 37: 621-632.

Submitted by Jennifer Poirier

The Carp of Malheur Lake

“The rooting up of the bottom and the constant mumbling of the mud has rendered the water almost opaque…”

“The native species evidently existed as a diversified group, while the introduced carp is capable of changing the entire community composition, bring about a change as marked as that produced by civilized man on the original vegetation.”

            -Alvin R. Cahn, 1929

"Gil" informs visitors to Malheur National Wildlife Refuge of the carp problems.

I recently visited Malheur National Wildlife Refuge in Oregon to get a first-hand look at their carp problem.  It’s a big problem.  Several years ago I attended a workshop at the refuge to learn about these issues (read previous blog post).  Malheur Lake proper is approximately 78 square miles (almost 50,000 acres) although this area fluctuates greatly from year to year depending on water inflows.  The lake is a remnant of an ancient lake that was once drained by the Malheur River (Snake River tributary) and the entire basin in larger than several U.S. states.  The basin is now closed and contains many wetlands and playas (Harney Lake) and is mainly supplied by the Blitzen, Donner, and Silvies rivers.   The lake once supported hundreds of thousands of nesting birds and providing a resting area for millions more – arguably one of the most important resting areas in the Pacific Flyway.  At least is used to be.  The lake is shallow and contained an abundance of submergent and emergent vegetation that provided a refuge and food source for invertebrates that birds like to eat.  No more.

Malheur Lake is 7 miles by 9 miles and once had abundant vegetation and millions of birds using it annually.  Now the lake is mostly devoid of vegetation.

The challenge of controlling the prolific common carp is daunting anywhere – much less on a lake the size of Malheur.  But actions are underway and all hope is not lost.  The entire basin is highly modified and numerous irrigation diversions are used to manage water to maximize bird production on the refuge and provide water for agricultural needs.  Portions of the refuge were added over time, as different ranch units.  This manipulation of waters results in a labyrinth of canals, diversions, and water control structures.  Even recently it was hard to sort all of this complexity out – and going to the “old timers” might have been your most reliable source of knowledge.  But things are changing – almost every inch of the water system has now been mapped and made available in a database.  A technician spent the better part of a summer armed with a 4-wheeler, GPS, and camera and travelled nearly every mile of every diversion and canal to locate and map every water control structure.

 

Malheur NWR has a labyrinth of diversions and water control structures.

Divide and Conquer     

So…the basin in highly manipulated and fragmented…often something biologists lament about.  This creates a perfect opportunity to start to partition off portions of the refuge to at least stop the carp from moving freely and better yet to kill them off in opportunistic areas.  Go for the low-hanging fruit.  In recent years many new and modern diversion screens have been installed to prevent common carp, as well as other fish like the sensitive redband trout from entering the diversions.  The fish are sent back to the river and the screens are meant to keep even the smallest fish and eggs from entering the diversions.  A brush periodically travels the length of the screen to keep debris from fouling and clogging the system.  For carp this means access denied to potential good spawning areas.

Fish screen on a  diversion from the Blitzen River.  The automatic brush that keeps the screen clear of debris is circled.

In addition, several new fish ladders have been installed at diversion dams on the Blitzen River.  These fish ladders provide passage for fish.  But we don’t want the carp to move around, right?  The ladders are equipped with fish traps.  Refuge staff check these traps daily – the native fish, redband trout, mountain whitefish, and Tui chub, among others are released upstream of the dam.  All common carp are removed and euthanized.  This is the beginning of a strategic approach to “divide and conquer” the common carp.  Conquer may be the incorrect term as past experience tells us that complete eradication of this prolific species is impossible – but suppression is the goal.  Recent research has indicated that carp levels below 100 lbs/acre may be a potential management target that minimizes the detrimental effects on a system and that the ecosystem may still function properly at this level.  Levels are definitely much higher than this in Malheur Lake.

Fish ladder on the Blitzen River leading to a fish trap.

Lifting the fish trap from the ladder.

Small male common carp captured in the trap.

Efforts are underway to explore the feasibility of commercially harvesting carp from the system.  Heck, humans have been pretty good at fishing other fish into submission, why not common carp?  Pulsed commercial harvest might improve conditions but likely needs to be conducted often, maybe every 2-3 years as populations can double quickly.  We are currently developing monitoring options to track the effects of carp suppression.  Hopefully the lake and refuge can once again be a great place for birds.

White-faced ibis on the Double-O Unit of the Malheur NWR.

Submitted by Jeff Jolley