Looking for Freshwater Mussels in the Chehalis River Watershed

We are initiating an exciting new project to learn the distribution of freshwater mussels in the Chehalis River watershed. Western Washington is home to three types of freshwater mussels--the Western Pearlshell, Western Ridged, and a diverse group of mussels called Floaters. Pearlshells and Western Ridged mussels typically inhabit streams and rivers while Floaters typically live in slow-moving water or lakes and ponds.

Western Pearlshell mussels

Freshwater mussels are useful as indicators of water quality and healthy fish communities. Mussels cannot move like fish so they flourish or perish with changes in environmental conditions. They keep records of change in their shell’s growth and accumulate compounds in their tissue. Some mussels are thought to live in the same place for over a hundred years! That is a lot of time and change in one spot. Mussels need a healthy fish community in order to reproduce. As young, they hitch a ride on the gills of fish and ride around the stream until they drop off and settle into the substrate where they will likely stay the rest of their lives. Don’t worry if you don’t see mussels, though--they are hard to spot and don’t live in every stream.

Snorkel survey in the Satsop River

Right now we are snorkeling and wading several Chehalis tributaries in Grays Harbor and Mason Counties and are finding Pearlshells as individuals and in large beds. We have also found a number of Floater shells, but no live mussels. This is not surprising, though, given the quick-moving streams we are targeting now. For the rest of the summer, we will be snorkeling and wading more streams, as well as working with biologists from Washington State agencies, forest resource agencies, and private firms to track down promising mussel locations. Knowing the type and location of the mussels will help us track their populations through time, providing us with important information about the health of the Chehalis River watershed and a better understanding of the role of mussels in the rich and diverse waters of the Pacific Northwest.

If you are interested in learning more about freshwater mussels, please visit the Xerces Society’s webpage where they have a free online field guide to Mussels of the Pacific Northwest.

A word of warning--Although you might be tempted to collect some mussels for yourself, it is illegal to eat or collect live mussels in Washington State. Besides, I've been told they are not the most appetizing creatures in the water anyway.

  

Skeleton of the Old Power Plant

The area of Renton, Washington, near Lake Washington has undergone numerous changes over the past 10 years.  One of these changes was the removal of the old Shuffleton Power Plant and its replacement with apartment buildings. Today, about the only thing left of the old power plant is a massive 656-foot-long metal flume which runs along the south shore of Lake Washington and is slowly rusting away. In addition, the flume is only about 1,600 feet from the mouth of the Cedar River, an important natal stream for anadromous salmonids. During plant operation, the flume served as the outflow for water from the power plant.

From January to April, large numbers of Chinook salmon fry leave the Cedar River and rear in the south end of Lake Washington. These fish prefer non-armored shorelines with sand and gravel substrates that have both open beaches and areas with riparian vegetation which provide woody debris and overhanging vegetation.  Unfortunately, the old flume has little of these habitat characteristics. 


Preferred habitat conditions--open beach (left) and riparian vegetation (right)--of
juvenile Chinook salmon in south Lake Washington


Chinook salmon are listed as threatened under the Endangered Species Act and resource managers in the Lake Washington area have been looking for shoreline areas that can be restored. The flume is an obvious choice because it is a large structure close to the Cedar River and is owned by Washington Department of Natural Resources (WDNR).

Juvenile Chinook salmon at night
in Lake Washington

Removal of the flume and other shoreline improvements will occur in late summer of 2011 or 2012.  From January to June 2011, our office will be working with WDNR to conduct snorkel surveys to gather information on juvenile Chinook salmon use under pre-restoration (current) conditions. Surveys are done at night when juvenile Chinook salmon are easier to observe and count accurately. The surveys are being done in three areas: (1) Along the flume wall; (2) an adjacent shoreline that will also be improved; and (3) nearby shoreline in Gene Coulon Park that will serve as a control site. Additional monitoring will occur after the restoration activities have been completed.

Surveying for Oregon Spotted Frogs in Western Washington

Love is in the air this time of year for many species of frogs around western Washington. With cool spring rain, male frogs find suitable areas for attracting a female mate, then use a unique call to attract females to the area. Many species of frogs will return to the water body where they were born to find a suitable mate.

Here in western Washington, several different kinds of frogs are found, including Pacific tree frogs and red-legged frogs. One species of special concern to U.S. Fish and Wildlife Service (USFWS) biologists is the Oregon spotted frog. Once widespread, this frog species may have been lost from at least 90 percent of its former range. Causes for the decline in frog populations include loss of habitat, non-native plant invasions, and the introduction of exotic predators such as bullfrogs.

Oregon spotted frog eggs

Around this time each year, USFWS biologists travel to the three areas in western Washington where Oregon spotted frogs are still known to persist. A survey of the area is performed to count the number of frog egg masses. When an egg mass is found, it is marked and monitored as it develops. Eggs typically hatch in 3 weeks and, once hatched, the young tadpoles graze on bacteria, algae, and plant tissue in the water.  By monitoring the egg masses, biologists can keep a close eye on the status of these populations.

Females deposit egg masses in shallow, often temporary, pools no more than 6 inches deep. Sometimes, though, the frogs choose areas where the water level drops, leaving the eggs high and dry. As you can see from the picture below, several Oregon spotted frog pairs chose the same area to lay their eggs. This large mass, which contained 16 individual egg masses, was found in an area where the water level had dropped. With careful and gentle hands, the eggs were moved by one of our biologists into an area that contained a bit more water. There the eggs will be able to develop and, in a couple of weeks, little tadpoles will hatch out and begin to feed.

Large egg mass before move to wetter habitat



Biologist's coat being used to move egg masses

Gently placing frog eggs in new home

With some habitat protection, population monitoring, and a little assistance from their two-footed friends, these Oregon spotted frogs will hopefully continue this cycle for many years to come in western Washington.

Checking in on Quilcene Coho Salmon!

A month has passed since staff from our office and Quilcene National Fish hatchery released the first group of coho salmon juveniles (fry) into the upper portion of the Big Quilcene River (see January 11 post).

We recently took a trip to the river to see where the fish have moved and to see if they are feeding and growing since leaving the hatchery. Our hope was that, once in the river, many of these fry would move around to find suitable shelter and food so they would stay healthy and continue to grow. And since we recorded the locations where fish were released, we were able to go back and see how many decided to stay where we planted them and how many had moved away. This information is important for several reasons--first, it allows us to determine if we are releasing the fry into areas that are good for growing coho salmon; and second, we can determine how many fry we can release into the area without overcrowding them.

There are several ways that biologists and technicians at our office count fish in streams and lakes. One way that is preferred by our office is to perform a snorkel survey. This method does not harm the fish because they are never caught with nets and handled. Visual counts by snorkeling are performed while the fish are active at night--this is when the fish come out of hiding from the stream banks and bottom to search for food in open water. The fish are less startled during the night and we can often swim beside them and watch as the coho look for insects and other natural food to drift by in the open water areas of the stream.

 

During our recent trip to the Big Quilcene River, we were able to snorkel several areas where we had planted juvenile coho this year and the findings were positive. Many of the fry moved downstream from the release locations and are now using more of the river to feed and grow; however, many of the fry found a suitable home right where we released them. The coho salmon fry all looked healthy as we swam around watching them search for and munch on natural food items. As the fry continue to grow, they will move further apart from each other, ensuring that they will have plenty of food and shelter. Hopefully they will keep growing and eventually leave the Big Quilcene River for Hood Canal and the Pacific Ocean before returning a few years later as 8- to 20-pound adult salmon.