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

Career Day at the CRFPO

The school bus stopped in front of the CRFPO first thing yesterday morning, an indication that the 3^rd annual “Career Day” was about to begin.  This year, a very enthusiastic  group of 6^th – 8^th grade students from Skyridge Middle School (32 in all) joined us for a half day filled with fish related activities.  Students rotated through four activities which included dissecting a trout and studying its internal anatomy, radio-tracking fish, learning about aquatic nuisance species by playing a full sized trivia board game, and playing 5 holes of mini golf while learning about salmon migration.  The day ended with lunch and a discussion about careers and fish management with the team of biologists who led the field activities.  Just before leaving for the day, all of the students eagerly raised their hands when asked if they would like to join us again; a sure sign of the day’s success.  

Fish Dissection

Radio Tracking

Salmon Migration Mini Golf

Aquatic Nuisance Species

  Submitted by Donna Allard

Blast from the Past: 1953 – Walt Disney’s Land of Exploration

In March, 1953 photographer Bert Harwell, nationally known wildlife photographer and bird caller, visited Malheur NWR. He was on assignment from Disney and showed a number of pictures while he was there which generated a lot of interest locally about the birdlife frequenting the refuge.  Bert Harwell used his images in films such as Disney’s “A True Life Adventure: The Vanishing Prairie” and “Canada West”.

Submitted by Nadia Jones

Code 17 - Radio Tagging at Warm Springs NFH

The sound of crickets chirping filled the room, only this was a completely artificially produced sound.  On the computer screen flashed “Code 17”, “Code 17”, “Code 17”.  The radio-tag was sending out its signal, waiting to be heard by those who were interested.  This small tag, measuring 5 mm by 10mm and weighing barely 0.3 grams, was placed into a bath of disinfectant, soon to be attached to a juvenile spring Chinook salmon.  It would accompany the fish on its journey to the sea.  The process had begun.

Top to Botton:  Pencil, PIT tag in vial, and radio tag.

 Jen placed an anesthetized fish onto the operating platform, belly up.  A tube was placed into the mouth of the fish, and a stream of water began flowing over the gills.  This water had a small concentration of anesthetic mixed in to keep the fish sedated throughout the procedure.  The fish’s gills rhythmically contracted.  Everything looked good.  Jen took a micro-scalpel and carefully made a small incision in the fish’s belly, just below the pelvic girdle.  She then used a small needle, covered by a plastic catheter to protect vital organs, to poke a hole in the fish’s abdominal wall.  The antenna of the radio-tag was then threaded through the catheter so that the antenna trailed outside the body wall, while the radio-tag itself could be placed inside the fish at the point of the first incision.  Satisfied that everything looked in place, Jen then proceeded to close the incision and finish the surgery.  Two sutures, using a modified surgeon’s knot, were “thrown” to keep the incision point tight and allow for natural healing.  After the first suture was complete, the flow of anesthetic water through the fish’s gills was switched so that only pure freshwater was flowing, beginning the process of recovery for the fish.  As the second suture was finished, Brian prepared a recovery bucket full of water with elevated dissolved oxygen levels.  Jen then placed the fish into the recovery bucket, and the time of surgery was called out and recorded.  Four minutes twenty seconds.  That was the length of time the surgery took, from placing the fish on the operating platform to depositing it into the recovery bucket.  Thirty seconds.  That was the time it took the fish to become fully awake and recovered from the surgery.  The fish was then placed into a holding tank inside the hatchery.  Code 17 was now the signal that would be broadcasting out from inside the fish for the next 42 days (the battery life of the radio-tag).  Code 17 was how we would now refer to this previously anonymous fish.  Code 17 was now part of our family, we would grow a special bond with it as we tracked its movement and progress on its journey to the sea.

               Why did we go through all of this effort to place a radio-tag in a fish?  Why did we do this 78 other times this April?  Why had Brian and Jen practiced surgery techniques for weeks prior to this?  Why had staff from Warm Springs NFH, the Confederated Tribes of the Warm Springs Reservation of Oregon, and the USFWS Columbia River Fisheries Program Office devoted so much time and effort to this project?  The radio-tagging project was part of a broader evaluation looking at juvenile survival of spring Chinook salmon released from Warm Springs NFH.  Warm Springs NFH, located on the Warm Springs Indian Reservation, annually releases up to 750,000 hatchery juveniles in order to provide adult spring Chinook salmon for harvest in the Columbia and Deschutes rivers.  The USFWS and the Confederated Tribes of the Warm Springs Reservation of Oregon have a comprehensive monitoring program designed to evaluate the effectiveness of hatchery rearing and release strategies in meeting the hatchery’s production and harvest goals.  Based on some previous evaluations using Passive Integrated Transponder (PIT) tags, it appeared that on average, less than half of the juveniles released from the hatchery survived to make it to Bonneville Dam, located on the mainstem Columbia River approximately 246 river kilometers downstream from the hatchery.  We wanted to know if the majority of this apparent juvenile mortality was occurring within the Deschutes River basin or was it occurring in the mainstem Columbia River. 

By radio-tagging a representative portion of the hatchery release, and then tracking the movements of the tagged fish in the Deschutes basin, we hope to determine whether fish are successfully making it to the mainstem Columbia River or whether mortality is occurring in the Deschutes.  Based on what we find, managers may be able to target actions to try to reduce the apparent mortality of the hatchery releases.  Surgically tagging the fish is only the first step in this process.  Tagged fish were then released into the Warm Springs River, along with the rest of the hatchery’s untagged population.  We placed a series of telemetry fixed-site stations throughout the Warm Springs and Deschutes rivers.  Fixed-site stations scanned the radio frequencies and recorded which codes were swimming past.  Based on the detection histories at each of the fixed-sites, we can estimate survival of the radio-tagged fish to various points within the basin. 

Code 17.  How is it doing?  Well, apparently darn good!  The fish was tagged on April 2nd and released from the hatchery on April 4^th.  Within eight hours of release, good old Code 17 had swum out of the Warm Springs River and into the Deschutes.  Less than thirty hours later it had swum past our fixed-site station at the mouth of the Deschutes River and was on its way down the Columbia.  That is swimming over 150 river kilometers of river in around two days!  This, from a fish that was just 132 mm in length.  We bid you adieu, Code 17, and hope your journey to the ocean is fast and uneventful.  Perhaps we will see you again in a couple of years, all grown and mature.  Maybe you will tell us more about your adventures upon your return.

Brian and Jen after a sucessful day of radio tag surgeries.

Submitted by David Hand

Blast from the Past: 1941 – Parade Float

In September 1941, Malheur NWR entered a parade float in the Harney County Fair parade. The float itself is a duck cage. The ducks had been banded prior to and were released during the parade. It was awarded 1^st place in the section representing government and municipal floats. This marked the 3^rd year in a row that they won first place. It’s probably a hard act to beat. I doubt city hall had birds to release. And who’s driving the tank?

Submitted by Nadia Jones

Tenacious Trespasser #5: Chinese Mitten Crab

Chinese Mitten Crab (Eriocheir sinensis)             

What is it?

The Chinese mitten crab is a freshwater crab named after the conspicuous mitten-like hairs on its claws.  These hairy bristles (or setae) might look like an interesting fashion statement, but their exact purpose is unknown.  Mitten crab can be found in bays and estuaries, as well as in freshwater rivers and streams with abundant aquatic vegetation.  Chinese mitten crabs are a catadromous species.  Catadra-what?  Catadromous refers to a life cycle in which organisms are born or hatch in the marine environment, migrate into freshwater where they spend the majority of their lives (2-5 years in the case of mitten crab), then migrate back to salt water to breed.  While in freshwater, mitten crab spend much of their time burrowed into riverbanks, hiding under rocks, or migrating upstream to find food. 

FACT: Polish researchers have discovered hundreds of tiny organisms living in the “mittens” of crabs.  They fear the mitten crab may transport its own nuisance species via its claws as it migrates to new habitats.

What does it look like?

Adult mitten crab are brownish-orange to greenish-brown in color with white tipped hairy claws (hair is greatly reduced or absent in juveniles).  Unlike native crab species, the shell or carapace of mitten crab is very convex and uneven, with a distinct notch between the eyes, and four spines along each side of the shell.  Legs of mitten crab are typically twice as long as the carapace width.

FACT: Chinese mitten crabs spend approximately 90% of their life in freshwater.

Where is it from & where is it now?

As its common name suggests, the Chinese mitten crab is native to the pacific coast of China and Korea.

The first notable invasion of Chinese mitten crab occurred in Germany in the early 1900’s.  It has since plagued a number of Northern European countries, as well as areas in Western Asia (Iran and Iraq), Canada and North America.  The first confirmed sighting of Chinese mitten crab in the US occurred in the Great Lakes in 1965.  Since this time, mitten crabs have been found in Chesapeake Bay, Delaware Bay, Hudson River, Mississippi River, San Francisco Bay, and the Columbia River.  The only self-sustaining population of mitten crab is currently found in San Francisco Bay, California.  It remains unclear whether mitten crab have established a population in the mid-Atlantic region.

General distribution of Chinese mitten crab populations.  Red circles and blue circles correspond to established and non-established populations in non-native range, green circles indicate distribution in the native range.  Taken from Dittel, A.I., Epifanio, C.E.  2009.  Invasion biology of the Chinese mitten crab Eriochier sinensis: a brief review.  Journal of Experimental Marine Biology and Ecology.  374, 79-92. 

FACT:  Single specimen of mitten crab have been captured in the Columbia River near Portland Oregon (1999) and Columbia River Estuary near Port of Ilwaco (1997).

How did it get here?

It is believed Chinese mitten crab were introduced to the US in one of two ways.  They may have been released intentionally to create a fishery and provide a food resource (in Asia, the mitten crab is a delicacy), or the juveniles (free floating larvae) were introduced to our waters accidentally through the transport of contaminated ship ballast water.

Today the mitten crab is still spread through ballast water discharge, intentional stocking, and by commercial or recreational boating activities.  Once introduced to a new location, it is possible the crab can migrate to surrounding water bodies on its own.

FACT:  This creepy crustacean can migrate up to 11 miles per day and will even travel on dry land to avoid barriers such as dams and levees.

What are its impacts?

You only make the Global Invasive Species Database’s list of “100 of the World’s Worst Invasive Alien Species” one way folks!  In high densities, Chinese mitten crab cause a number of problems in their introduced range.  They may out-compete native crab, mussels, and crayfish for food and space.  Their voracious appetites can completely alter the aquatic food chain and cause a general decline in the species it competes with and/or consumes (e.g., algae, aquatic plants, detritus, benthic invertebrates, salmon/trout/sturgeon eggs).  The burrowing activity of Chinese mitten crab can undermine levees and significantly increase the occurrence of stream bank erosion.  Mitten crab may impact commercial and recreational fishing industries by consuming bait, inundating or damaging fishing nets and devouring or damaging catch.  In California, massive migrations of the crab have clogged screens, pumps, water intake structures at fish collection facilities and power plants.  The mitten crab can even be a threat to human health – as they are an intermediate host of the Oriental lung fluke.  Humans become infested if raw or undercooked crabs are eaten.  Fortunately the fluke has not been found in mitten crab collected within the United States.  

FACT: Female mitten crab produce 250,000 to 1 million eggs per brood.

What is being done about it?

A number of control methods such as trapping, trawling, physical barriers, and harvest programs have been used to battle this mitted monster with limited success.  Chemical controls are generally not considered a viable option to combat mitten crab because of their mobile nature.  However, research on a fungus that is lethal to mitten crab may prove to be an effective biological control agent in the future.  For now, federal legislation (Federal Lacey Act) has made it illegal to import eggs and live mitten crab to the United States.  It is also illegal to transport or possess live mitten crab in the states of California, Washington, and Oregon (OAR 635-056).

Public outreach and education remains the best most cost effective method of preventing the introduction and spread of Chinese mitten crab.

FACT:  English researchers have considered selling invasive Chinese mitten crab to restaurants and markets as a way to control their numbers.

How can YOU prevent the spread of Chinese mitten crab?

Aquatic nuisance species have the uncanny ability to hitch a ride in places we least expect them.  To minimize the potential spread of unwanted invaders, follow these simple steps.

·       CLEAN: your boat and all your gear including waders and boots after each use.

·       DRAIN: all of the water from your boat (including the bilge, live well, motor), trailer, tackle and gear before leaving the area.

·       DRY: your gear completely (at least 48 hours) after each use.

·       NEVER: move live organisms from one water body to another – it is illegal!

·       If you happen to capture a mitten crab, DO NOT throw it back alive.  Take a photograph, freeze it or preserve it in rubbing alcohol, and report your finding to a local authority.

What if I find a mitten crab?

If you find Chinese mitten crab or any other “tenacious trespasser” contact the Aquatic Nuisance Species Task Force at 1-877-STOP-ANS.  If you spot a potential aquatic invader in Oregon, contact the Oregon Invasive Species Hotline at 1-866-UNVADER.  In Washington State you can report a potential sighting at 1-877-9-INFEST.

Submitted by Jen Poirier