Wednesday, September 29, 2010

Olympic Mudminnow – Western Washington Wetlands Survivor

Olympic mudminnow
Olympic mudminnow
The Olympic mudminnow is a small fish that only occurs in western Washington. Olympic mudminnow live in marshes and wetlands with a muddy bottom and abundant aquatic vegetation. Typically they do not occur where there are large, predatory fishes, such as largemouth bass. They eat fish larvae, eggs, and small invertebrates, and have a remarkable tolerance of low oxygen levels. The Olympic mudminnow may be an indicator species to monitor the potential impact of climate change on wetlands and fish in western Washington.

Western Washington wetland
Western Washington wetland

The Washington Department of Fish and Wildlife (WDFW) conducted mudminnow surveys in past years and created a database of inhabited sites. Our office is currently working with WDFW to revisit several of these sites to see if these fish are still present. Upon capture of a mudminnow, we remove a small part of the caudal fin for genetic analysis to help us determine the relative uniqueness of each Olympic mudminnow population. This is our first year working with this unique species and we plan to collect more data at additional sites in upcoming years.

Thursday, September 23, 2010

Pacific Lamprey - An Unusual Fish

Pacific lamprey being measured
Pacific lamprey being measured
With the decline of lamprey in many rivers of the Washington Coast work is being conducted by the U.S. Fish and Wildlife Service to better understand why.

One type of lamprey that is of special concern is the Pacific lamprey. Lampreys are an unusual fish that resembles an eel, even though they are not related. They are a very important food source to fish, birds and mammals. Pacific lampreys spend more than half of their life buried in sandy or muddy spots of the river. Like a salmon, when the timing is right, young lampreys will move from their home in the river to the waters of the Pacific Ocean. Adults will return to the rivers and move upstream to lay eggs after spending a couple of years at sea.

Work on the Big Quilcene River has begun to see how well the lampreys are doing. To do this, lampreys are coaxed out from the river bottom using a mild electrical current that stuns them long enough to be captured. After a few measurements are taken on each lamprey, the fish are released unharmed at the same spot in the river where they were captured.
Biologists looking for lamprey in the Big Quilcene River
Looking for lamprey in the Big Quilcene River

Friday, September 17, 2010

Coho Have Returned!

Sorting coho salmon at Quilcene National Fish Hatchery
Sorting coho salmon

It’s that time of year again when thousands of coho salmon return to Quilcene National Fish Hatchery after having spent the last year and a half feeding in the Pacific Ocean.

Our office coded-wire tagged a portion of these fish as juveniles in 2008 in order to measure their survival. We test the returning fish with magnetic detectors to identify those fish that still have tags. The tags are removed and read and the survival rate calculated. Quilcene coho survive at a fairly high rate, so after a day of sampling hundreds of fish for tags our arms are pretty worn out. This year we're especially tired---Hatchery Assistant Manager Dan Magneson said that these are the biggest fish he can recall in recent memory.

Please visit Quilcene National Fish Hatchery to see us in action or to enjoy a guided tour. Tours can be arranged by calling the hatchery at 360-765-3334.