Tuesday, August 28, 2012

Bull Trout Redd Surveys in Northern Puget Sound

Bull trout
Bull trout (Salvelinus confluentus) are a member of the salmonid family, which includes salmon, trout, whitefish, char, and grayling. Bull trout love cold, clean, complex, and connected streams and other aquatic habitat. Habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, the effects of climate change and past fisheries management practices, including the introduction of non-native species such as brown, lake, and brook trout, have resulted in local extinctions and population declines of bull trout. This has led to the listing of bull trout as threatened under the Endangered Species Act in 1999. Within the Puget Sound Bull Trout Management Unit, there are eight core areas with a total of 57 identified local populations. Bull trout are found in the Chilliwack, Nooksack, lower and upper Skagit, Snohomish-Skykomish, Stillaguamish, upper Cedar (Chester Morse Lake system), and Puyallup River basins. With the exception of the Chilliwack and upper Cedar River systems, these basins all support anadromous bull trout that use Puget Sound marine waters for foraging and migration.

A high priority goal of our agency is to acquire more complete information on the current distribution and abundance of bull trout within each core area of the Puget Sound Management Unit. Annual spawning nest (redd) counts provide a non-invasive way to monitor relative population strength of bull trout. Each fall, experienced fisheries personnel count the number of redds in predetermined stream sections. Not all known bull trout spawning areas are monitored, since weather and remoteness limit the ability to conduct the fall surveys in some areas. Comparison of the count numbers over time can provide insight into long- and short-term population trends and alert fishery and land managers to potential problems within aquatic systems.

Since State funds for surveying bull trout redds was no longer available, we provided money to the Washington Department of Fish and Wildlife (WDFW) to continue collecting this valuable data through return year 2011 and to expand the number of survey sites. Staff from WDFW surveyed for bull trout redds within the Skagit, Snohomish, and Stillaguamish River basins from 2009 to 2011. Their findings include:
  • Fewer bull trout redds were observed in the past 3 years than were observed from 2006 to 2008.
  • The total bull trout redd count was very similar in 2011 to what was observed in 2010. However, some areas had more redds than in 2010 and some had less.
  • The total redd count of all sites (637) was 25% below the average count from the years 2006 through 2010 (850).

You can learn more about bull trout biology, critical habitat, and conservation measures at http://www.fws.gov/pacific/bulltrout/


Monday, August 20, 2012

Documenting the Olympic Mudminnow Family Tree

Mudminnow habitat - Connor Creek, Grays Harbor County
This June and July, Fish Biologist Roger Tabor and I hit the highways and dirt roads of western Washington in search of undiscovered and established Olympic mudminnow (Novumbra hubbsi) sites to complete the story of Olympic mudminnow population genetics. That just means we are documenting the Olympic mudminnow family tree to see who is most closely related and where the founding fish for each population may have come from. This type of information will help us down the road as we initiate discussions with our partner agencies and the public about developing a strategic habitat conservation approach for Olympic mudminnow.

Even before we hit the road with our boots and nets, there was a lot of planning and collaborating for Roger to do. He and fellow biologists here at USFWS and Washington Department of Fish and Wildlife (WDFW) are working together to research documents and historic data to uncover places where Washington’s only endemic fish were found in the past. This saves us time and money, keeps us from driving to every pond and ditch that looks promising, and allows us to identify land owners so we can ask for permission to access and sample on their property. Once the ground work was done, Roger and I hit the road in search of the mudminnows.

Roger Tabor looking for Olympic mudminnows
in Steamboat bog
Over the course of 5 days, we visited 12 sites and were able to capture hundreds of mudminnows from six targeted localities from Chehalis and along the Olympic Peninsula to Quillayute. We averaged less than a minute per mudminnow (that’s faster than 60 mudminnows per hour!) as we measured, weighed, sexed, and clipped each one. We only took a small bit of tissue from the caudal fin for the genetic clip sample, so we were able to release the mudminnows back to their respective home after a short rest in the "recovery bucket".

Even though our target is genetic samples, I cannot help becoming interested in the many differences and similarities between locations that mudminnows call home. All the sites were in very flat, barely flowing water with vegetation growing in the water and on the edges. We visited shady coastal creeks less than a mile from the ocean, sunny sphagnum bogs, lily-pad ponds, and wetlands at the corner of two busy roads. In some locations, our nets and traps caught up to four other fish species, giant water bugs (which still lurk in my nightmares), dragonfly nymphs, salamanders, frogs, freshwater mollusks (clams and snails), crayfish and more, while in other locations it seemed to be just the mudminnows and us.

For our samples, it’s a quick trip from biologist to geneticist and on to improving our understanding of the history and biology of mudminnow populations, painting a broad picture of how the mudminnows got to be where they are today, and possibly where they might be heading in the future. I, for one, cannot wait to see the results.

---Teal Waterstrat, STEP Student