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

Blast from the Past - Snippets from the Refuge Archives

I’ve been handed an amazing project: the refuge archives!! I know. Dull, right? Not at all! Sure, there’s the humdrum bureaucratic stuff: how many man hours does a fence require? How many birds were tagged? But there are also stories about daily life and special events. In this series, I plan to share whatever fun tidbits I run across as I sift through the history of our National Wildlife Refuges.

Blast from the Past: 1956 - Color Marking Study of Migration Routes

How would you determine the migration routes of birds without radio tags or GPS or really computers in general? During March & April, 1955 around 850 Ross’s Geese (white birds) were trapped and dyed vivid colors (pink, yellow, and green) near Tule Lake, CA. This was done to see if the tracking rates would be better than banding. It was noted that the geese were accepted back into the flock despite the outrageous coloring. Studies like this are entirely dependent upon the reports of observers and the scientists involved hoped that the distinctive, non-natural colors would attract attention. By late April of that same year reports started coming in: 2 pinks had arrived in Burns, OR. In May, 2 in Alberta, 2 along the Mackenzie River, and 2 near the Arctic Coast. In July, a green was banded on Banks Island. No pictures were included with the study documents – oh how I wish there were some!!

  Submitted by Nadia Jones

Ring the Bell, Pacific Lamprey are in School!

School?  For lamprey?  That’s right.  Pacific lamprey are now in local schools.  They don’t take the bus every day.  They don’t have math homework at night.  They don’t take tests and they don’t get sent to the principal’s office.  Rather, they are there to help teach as many students as possible, young and old, what makes this fish unique.  Given that lamprey have been around for at least 360 million years, it makes sense that humans (who have only been around for about 100 thousand years) can probably learn a thing or two from them!

We’ve been fortunate to be involved in an outreach program established by the U.S. Fish and Wildlife Service’s Sean Connolly to get “Lamprey in the Classroom.” This program involves setting up an aquarium in a classroom, collecting a few lamprey from local streams, and placing them into the aquarium for the students to observe and learn from.

Lamprey have a complex life history.  For example, Pacific lamprey embryos hatch in freshwater tributaries.  The resulting larvae—known as ammocoetes—do not have eyes, spend much of their time burrowed in sediment, and feed by filtering water.  Sometime in the next 3-7 years they go through a transformation (metamorphosis) into juveniles, called macropthalmia.  Juveniles have eyes and teeth to help with feeding when they eventually head out to the ocean.  After a period at sea, the lamprey transform again into fully mature adults, return to a freshwater tributary to spawn (after which, adults die), and start the cycle once again.  You can learn more about this life history, and improve your coloring skills, by clicking HERE.

 

The Lamprey in the Classroom project has helped bring larval lamprey into two Portland (OR) and Vancouver (WA) metro area schools.  Middle and high school students are observing and caring for the fish in their ammocoete (larval) life history stage, when lamprey don’t have eyes and feed by filtering water.  Students can observe, study, and wonder why they can never find the larvae, set up cameras to try and catch glimpses of the elusive critters, and ask really cool questions about this ancient species.  Pretty much how all great scientists get started, right?  Hmmm … so all this observation got students at David Douglas High School and Pacific Middle School thinking … “How should we feed these lamprey so that they will stay alive and grow?”  GREAT QUESTION! 

 

Right now, there are a lot of biologists from tribal, state and federal agencies as well as colleges and universities asking the same thing.  Many folks are wondering if we an bring some lamprey into captivity to help conserve the species.  Although we know we can keep them alive for at least 2 years, we still need to know (or learn) how to get them to grow well.  Fortunately, we have also been able to work projects to help understand what and how to feed these larvae.  The most common food used to feed larval lamprey in captivity has been yeast (that’s right, the same stuff you might use for baking bread).  Although yeast seems to work perfectly fine in some cases, researchers are starting to explore other possibilities for feeding the larvae.  As part of the Lamprey in the Classroom project, some of our research results have been able to provide students with information on what and how to feed larval lamprey. 

 What seems pretty certain is that - while students might want to consider bringing an apple for their teacher - for now, it would probably be better to bring something like yeast for their lamprey.

Submitted by: Tim Whitesel, Sean Connolly and Marci Koski

Photos by Jane Chorazy

 

Prevent the Pathway!

It is National Invasive Species Awareness Week...so let's take a look at the different ways some of these species invade or spread to new areas.

Aquatic nuisance species (ANS) can come from any country in the world and may be introduced into new ecosystems in a variety of ways.  The means and routes by which ANS are introduced into an aquatic ecosystem are called introduction pathways.  Some species migrate into new areas on their own (volitional movement), while others may be carried into new areas by natural events such as hurricanes or floods.  The vast majority of invasive species are spread into new water bodies as a direct result of human activities.  Whether intentionally or by accident, once an ANS is introduced and becomes established in a new ecosystem, it is very costly and difficult to control or eradicate them.  Often the best approach to preventing the introduction or further spread of ANS is to educate the public on the potential pathways of introduction and steps each person can take to stop the spread of ANS in their local community. 

Look at the following picture and identify 10 ways in which ANS are introduced or spread into local aquatic ecosystems.

National Invasive Species Awareness Week website

Submitted by Donna Allard and Jen Poirier

Tenacious Trespasser #4: New Zealand Mudsnail

New Zealand Mudsnail

(Potamopyrgus antipodarum)

What is it?

The New Zealand mudsnail is a tiny aquatic snail that inhabits lakes, rivers, streams, reservoirs and estuaries.  In addition to mud, the snail can also be found lurking on rock or gravel surfaces, aquatic vegetation, or woody debris.  New Zealand mudsnail are highly adaptable to diverse climates and can tolerate a broad range of aquatic conditions such as temperature, salinity, turbidity, water velocity, and stream productivity.  In the United States, New Zealand mudsnail populations are comprised almost entirely of self-cloning parthenogenetic females (no need for fertilization here).  The brood size of an individual female ranges from 20-120 embryos, each of which may mature to produce an average of 230 offspring per year – these gals could show Dolly the sheep a thing or two!       

FACT:  A single female mudsnail can result in a colony of 40 million snails in one year. 

What does it look like?

You better get your glasses out because this miniscule menace is only about 4 – 6 mm (1/8 inch) in length as an adult.   The snails shell is light to dark brown, with five to six whorls or spirals.  The opening of the shell has a retractable cover called an operculum which allows the snail to seal itself inside when it feels threatened or is exposed to pollutants.  Some fish and birds feed on New Zealand mudsnail, but the rigid operculum and thick shell wall enable many snail to pass through the digestive system of predators unharmed.    

FACT:  New Zealand mudsnails consume but cannot be consumed.  They hold no nutritional value for native fish species.

Where is it from and where is it now?

As its common name implies, the mudsnail is native to New Zealand and its neighboring islands. 

The New Zealand mudsnail has been introduced to Australia, Europe, Asia, and North America.  In the United States, the New Zealand mudsnail was first discovered in the Snake River (Idaho) in 1987.  Since this time it has become established in ten western states, five Great Lakes states and two Canadian Provinces (British Columbia and Ontario).

Benson, A.J. 2011.  New Zealand mudsnail sightings distribution.
Retrieved 2/26/2013 from newzealandmudsnaildistribution.aspx.

FACT:   The mudsnail’s ability to completely seal its shell allows the snail to survive out of water for several weeks in cool, damp conditions.

How did it get here?

The New Zealand mudsnail was first introduced to the US through contaminated ship ballast water and/or the transport of live fish or eggs for the commercial aquaculture industry.  Once introduced to a region, snails may be spread locally on the fur or feathers of terrestrial wildlife and pets (that means you fluffy), or consumed and dispersed in the excrement of local fish species.  Long distance dispersal of New Zealand mudsnail has been attributed to ballast water discharge, the movement of commercial aquaculture products (i.e., fish, eggs, and ornamental plants), and the transport of contaminated recreational gear.  This sneaky snail has an uncanny knack for hitchhiking on wading gear, nets, boats, and trailers of fishermen, boaters, and other water users, allowing it to be unknowingly spread to new areas.          

FACT:  Mudsnails can crawl at a rate of up to 10 feet/hour – these gals can really get around!

What are its impacts?

The high reproductive potential of New Zealand mudsnail enables it to reach extraordinary densities in some locations.  Researchers at Montana State University have reported densities of up to 750,000 snails per square meter in Yellowstone National Park.  Large colonies of New Zealand mudsnails can comprise up to 95 percent of the total macroinvertebrate biomass, and consume up to half of the available food in a stream.  New Zealand mudsnail may outcompete or displace native snails, mussels, and aquatic insects which native fish species depend on for food.  This disruption to the food chain may ultimately result in reduced growth rates and lower populations of economically important fish species.

FACT:  In Australia, New Zealand mudsnails have emerged from domestic water taps - gross!   

What is being done about it?

Once this horrible hitchhiker invades an area, there is very little that can be done to control or eradicate them.  Researchers are investigating the potential use of a host specific trematode to control the snail, but it is unknown how this parasite might impact native snail populations. 

Because the spread of New Zealand mudsnail is strongly associated with human activities, public education and outreach is still the best method to prevent their introduction and spread to new areas.  Informational signs are posted at boat ramps where New Zealand mudsnails have been found to alert boaters of their presence and what special precautions should be taken to minimize the risk of spread.  Many states (including Oregon) have mandatory boat inspection stations at state lines, boat ramps, and rest areas, where boats and other watercrafts are thoroughly inspected for the presence of mudsnails or other aquatic nuisance species.  If any are found, the boat is decontaminated on site at no cost to the owner.

FACT:  The New Zealand mudsnail has no natural predators or parasites in the United States.  In its native habitat, 11 different species of parasitic trematode keep mudsnail populations to a manageable size. 

How can YOU prevent the spread of mudsnails?

The small size of New Zealand mudsnails make them very easy to overlook and accidentally transport to new locations.  To minimize the potential spread of this tiny terror, follow these simple steps.

·       CHECK all recreational gear and clothing that has come in contact with water for any visible signs of sand, mud, or plant fragments which may indicate a tiny hitchhiker.

·       CLEAN all gear before leaving a site by scrubbing with a brush and rinsing with water.

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

·       DISINFECT your gear (especially waders and boots) before traveling to a different water body.  Freeze your gear for a minimum of 6 hours (< 26°F), soak gear in a hot water bath for 5 minutes (≥ 120°F) (not recommended for Gortex), or soak gear in undiluted Formula 409 for at least 10 minutes. (http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev3_015418.pdf). 

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

·       NEVER transport live fish or any other aquatic plant or animal from one water body to another – it is illegal!

What if I find New Zealand mudsnails?

If you find New Zealand mudsnails 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 Donna Allard

Shifting Gears, Moving On...

The time has come for me to shift gears into a slightly different occupation  I think working with technology is super because the complexity naturally satisfies human curiosity while at the same time enables us to be more lazy -- by accomplishing more things with less effort -- which is definitely on my spectrum of human nature.

Working as an IT-Specialist at Columbia Fisheries Office is not just about technology however, it's about people. Specifically, people who value learning and expertise, value preserving our ecosystem and are smashingly good at optimizing constraint satisfaction problems with many human stakeholders. And while working for the biggest organization in US, the US, has its perks it certainly requires a particular finesse to have all gears greased and protocols followed.

I have tremendous respect for the work performed at CRFPO and feel lucky being partially involved over the last few years. I wish good luck to finding a replacement IT and of course a bigger budget for the years to come.

Submitted by Val Pavlenko

Best of Luck to you!

Restoration and Human Safety… Fish Passage Projects with Multiple Benefits

Working on private lands habitat restoration projects is a blend of science and art.  Our big picture strategies are guided as much as possible by the best scientific information in large-scale habitat assessment and resource prioritization plans.  We try to focus on strategically addressing the habitat limitations (the ‘life-history bottlenecks’) for key species like salmon across a wide variety of different land ownerships – including private and municipally owned lands. 

In several of our watersheds we have detailed assessments of road crossings (usually culverts) that are blockages to fish movements in rivers and streams.  The culverts are usually far smaller than the stream’s width, resulting in excessive velocities and scour that creates a drop, or perch, at the downstream end. We use the detailed assessments to select barriers that are ‘high priorities’ to address.  This is based on the length and quality of upstream habitat as well as on the number of at-risk or focal fish species that use the stream. But knowing where to work is just the first step.



Perched culvert in Roy Creek before restoration.



The day to day efforts are all about building relationships and partnerships.  That’s where the art comes in.  Working with a diverse array of partners and their broad range of goals means we have to find a way to achieve benefits for everyone while still being true to the intent of our conservation funding.  When you add a sluggish economy and declining budgets to this mix, it really gets interesting.  The collaborative mode is rewarding in itself, but it is also necessary when everyone has fewer resources.   The success of this work is really visible in some of our current restoration projects on Oregon’s north coast.  In addition to selecting projects that are high priorities from a natural resource standpoint, we also look to support critical infrastructure upgrades and to improve public safety.  All of the projects are beneficial to the local economy in that there are lots of jobs and materials purchased.



Seaside Heights Elementary students visit the new culvert
to learn about coastal streams.



Seaside Heights Elementary—When the Seaside School District learned that the culvert under the only access road to Seaside Heights Elementary School was failing and that it would cost nearly a half a million dollars to fix it, they were concerned about the welfare of their 320 students and their families who travel over the culvert daily.  The school had also been designated as a Tsunami Safe Area for the community, making safe access even more critical.  The school didn’t have cash or resources to fix the culvert, but an expedient and creative partnership between Seaside School District, USFWS, Necanicum Watershed Council, City of Seaside, Oregon Department of Fish and Wildlife, NOAA-American Rivers, and Oregon Watershed Enhancement Board provided design, permitting, and funding to fix it. The culvert was not only a failure risk; it was a barrier blocking migrating fish from nearly a mile of spawning habitat.  Culvert failure would have dumped 10,000 cubic yards of earthen fill into the stream, damaging habitat quality in the creek and in the productive beaver marsh below – both important rearing habitats for juvenile fish.  Working together, our team of partners installed a 16’ wide by 150’ long culvert with a natural stream bottom to ensure that adult and juvenile fish could move upstream and downstream at all flows.  The school got state-of-the art infrastructure and the City of Seaside got a secure access to a Tsunami Safe Area for their residents.  The school continues to work closely with the watershed council to use the stream as an ‘outdoor’ classroom to engage their students.

Tillamook County—Another important partner has been Tillamook County.  We have culvert assessments and prioritizations that cover nearly the entire county.  This has allowed a broad team of partners to work together to strategically implement projects that open streams to enable fish to move into quality habitat.  Local organizations, like the Nestucca-Neskowin Watershed Council and the Tillamook Estuary Partnership, have been important leaders in gathering the data and coordinating partners.   The Tillamook County Public Works Department has been a great cooperator as well, realizing that much of the infrastructure is under their jurisdiction yet they have extremely spare budgets to address the pressing needs-- even in the case of culverts at risk of failing.  Our projects in Tillamook County have helped salmon, steelhead, trout, and lamprey access important upstream habitats.  At the same time, these projects have also helped improve the City of Tillamook’s drinking water diversion and have fixed a barrier culvert under a county road and Port of Tillamook Railroad crossing.  This coming summer we will fix at least three other important county road crossings, including one that is in imminent risk of failing, and will work on several private lands fish passage projects this summer; providing fish and stream benefits while ensuring safe access to farms and homes, and for logging and gravel trucks and other coastal dwellers to travel a safer road network. 

Achieving the Mission—In the end these projects meet many goals.  They improve fish access to miles of important habitat and improve stream dynamics by removing artificial constrictions to restore natural stream flows and reduce scour of stream habitat features such as spawning gravels.  The projects help repair failing infrastructure that poses human safety risks.  They can help provide secure drinking water resources.  They stretch limited local municipal budgets in tough economic times.  They create an efficient and seamless partnership between local, state, and federal agencies where everyone contributes an essential piece in a complex puzzle. 

Tillamook county Commissioner Mark Labhart
speaks at the Roy Creek Ribbon Cutting Celebration.

The value of this type of partnership was recognized by Senator Betsy Johnson at the ribbon cutting ceremony on the Roy Creek Fish Passage project in Tillamook County last November, “This is really a big deal.  This goes to show what we can accomplish when we work together.” Her thoughts were echoed by Lower Nehalem Watershed Council Chair George Hemmingway, who said, “This just shows what can be done when people at the local community level, stakeholders and leaders, are encouraged and aided by government agencies at all levels. Bottom up and grassroots thinking, aided by county, state and federal experts and funds. What an idea…very Oregonian.”

And, last but not least, they achieve the Fish and Wildlife Service mission, which is after all, working with others to conserve, protect and enhance fish, wildlife, and plants and their habitats for the continuing benefit of the American people.

Submitted by Amy Horstman, Fish and Wildlife Habitat Restoration Program