Tracks in the Snow

After a cold and snowy day at the Hatchery, the crew arrived the next morning to find evidence of an overnight visitor.  The oversized tracks were nearly as long as a human foot and eerily resembled what a Tyrannosaurus Rex might have looked like.  Fortunately, this was not a T-rex, but rather a relatively common Great Blue Heron, Ardea Herodias.  One could imagine this tall bird walking along the perimeter of the Hatchery peering into what must be a heron Shangri-La;  2.1 million budding steelhead smolts at just the perfect snacking size.  Unfortunately, for the Hatchery’s guest, the bird netting was an effective deterrent and the tracks never re-appeared within the confines of the fish production area. 

The tracks were a reminder to the constant vigilance the Hatchery crew maintains to repair netting and keep the area predator free.  A Great Blue Heron does not eat that many fish as compared to the millions of smolts supported at the Hatchery.  However, a larger problem occurs by the transfer of smolts and water across rearing containers.  The transfer issue can cause disease contamination.  In the Hatchery setting, disease prevention is the best cure.  One transfer of a virulent disease can cause substantial fish losses.  In the past, the Hatchery has encountered infections of Infectious Hematopoietic Necrosis (IHN) that has caused mortality rates of over 50%!  So despite, the Great Blue Heron’s regal stature and fit into the natural ecosystem, he is an unwelcome guest here at the Hatchery.  We wish him luck on his hunting adventures as long as they aren’t here!

The following photos are from the William L. Finley National Wildlife Refuge in Benton, OR.

Photo credit: George Gentry/USFWS

Photo credit: George Gentry/USFWS





Photo credit: George Gentry/USFWS



Hatchery Technology Improvements

Dworshak Hatchery has a new chiller.  The chiller is used to cool water used to incubate Chinook salmon eggs in the incubation room (See December 9 posting).  This chiller replaces the original chiller which dates back to the 1980’s.  The old chiller was barely running and was only able to chill the water a few degrees.  Our new chiller is taking incoming water at 44 degrees and chilling it to 36 degrees.   Without the chiller, the incubating eggs would have hatched long ago and would need to be placed in rearing tanks soon.  Since there is no space for the small Chinook salmon right now, this would be a huge problem.  With the chiller operating, the juvenile Chinook will not need to be placed in rearing containers until April.  Last years’ Chinook salmon will have been stocked by then and the Chinook raceways will be empty and ready for another production cycle.

Dworshak's new water chiller, pre-installation

The new chiller is a significant technology advancement over the old chiller.  It is easier to program, utilizes less power to run and occupies a smaller footprint.  Eventually, the waste heat from the chiller will be tapped to heat one of the buildings.  This will save even more energy helping to meet the government's initiative to decrease power consumtion and be more green.

Northwest Fish Culture Conference

Armed with fresh passports, several members of our hatchery crew eyed the border guard with uncertainty.  However, with a friendly "Where you headed, eh?", we were cleared through customs and headed to Victoria, British Columbia to attend the 62nd Northwest Fish Culture Conference.  This conference is a joint venture of States, Agencies, Tribes, Private ventures, and Provincial governments concerned with fish culture in the northwest.  Victoria's inner harbour provided a tremendous backdrop for the venue at the Historic Fairmont Empress Hotel.

Victoria's Inner Harbor

The view was complete with a festive decoration of the Parliament building and several totem poles honoring the traditions of this unique area.  Since many of the programs in the Pacific Northwest are closely tied to salmon and trout species, Victoria provided a great host for this venue.

A festively-lit Parliament Building, in Victoria, BC

Totem Pole

Of course, the conference was front and center stage.  The agenda covered a great depth of discussions ranging from New Investigational Animal Drugs to recirculating aquaculture systems and survivability issues in triploid salmonids.  The hatchery staff members spent their days scribbling notes and tracking down the latest innovations in the business.  After-hours were spent with old friends and new acquaintances.

The crew also took an impromptu field trip to the Vancouver Island Trout Hatchery to look at some retrofitted partial re-use systems.  These systems used an airlift pump to circulate, strip carbon dioxide, and re-oxygenate the water.  With this system, the Vancouver Hatchery was able to reduce water usage by almost 70%!  Despite the cold temperatures (-4 C), the Dworshak crew was excited to brainstorm ideas on how this could be applied in the future on the short trip back from Duncan to Victoria.

A tour of Vancouver Island Trout Hatchery

Time flew by during our visit and before we knew it, we were headed back to the hatchery re-invigorated with new ideas to solve the never-ending myriad of fish culture challenges we face daily.  How bout' that, eh?

The Pitter Patter of.....Little Fish!

Within the cold, dark Heath trays of Dworshak’s incubation room an exciting transformation is taking place. Eggs that were spawned from returning Chinook salmon last August are beginning to hatch. Alevin, or yolk bearing fish larvae, are breaking free from their shells and beginning their first stage of life as fish. Although free from the confines of the corion, or egg shell, alevin are quite limited in mobility and still depend on their yolk sac for nutrition. In the wild alevin remain in the shelter of the gravel redd for several weeks after hatching. Once most of the yolk sack is absorbed the tiny fish will emerge from the gravel as fry, about 1 inch long.

Stacks of Heath style incubators stand like soliders in Dworshak's incubation room.

At the hatchery, alevin remain in the safety of their Heath trays making a slow but steady transformation from larvae to fry. Newly hatched Chinook have many developmental milestones to reach before they can survive life outdoors.  Just after hatching these tiny alevin don’t appear very fish like. Externally their fins will continue developing over the next few weeks and internally their digestive system has yet to form completely. 



Newly hatched Chinook alevin hardly resemble fish...




...but in a few months they will look like this!

 

Temperature plays a huge role in the rate at which salmon develop. The ideal rearing temperature for Chinook salmon from egg to fry is about 8 °C (46.4° F), but rearing temperatures can range from between 4-12° C (39-54° F). A rule of thumb is the colder the water the slower development will be. In fact it is common practice in aquaculture to use temperature units (TU) to estimate the critical stages of egg and fry development.  One TU is equal to one degree Fahrenheit above 32° F for every day of incubation. So under an ideal rearing temperature of 46° F Chinook salmon gain 14 TUs a day. In general, Chinook salmon eggs reach the eye up stage at 450 TUs, will hatch at 750 TUs, and will emerge around 1600 TUs.

Eyed Chinook eggs with a few newly hatched alevin

The 2011 brood year of Chinook salmon are at about mid-hatch and will continue their exciting, yet inevitable transformation into tiny fish. The majority will grow up strong and healthy at the hatchery and enter the Clearwater River in the spring of 2013. It is amazing to know that many of these fish will survive and live in the ocean for as much as 5 years; but like their parents before them instinct, determination, and good fortune will direct them back to Dworshak where they will pass along their legacy to the next generation of Chinook salmon.

Ten Things We Are Thankful For...

1.       Our military; all the soldiers who bravely and selflessly give to keep our country safe and free.

2.       To work at a place where you can look down at the Clearwater River and see steelhead rising to the surface and you can look into the sky and see golden eagles soaring overhead.

3.       The bountiful fish, wildlife, and agricultural resources of this part of the country.

4.       Family.

5.       Open spaces; land that has been touched by the hand of the God and not much else.

6.       To have the opportunity to work with so many interesting and thoughtful people.

7.       To be healthy.

8.       For the seasons

9.       For the energetic and progressive thinkers that have given Dworshak a bright future.

10.   To be able to take time off to spend with friends and family.

This List was complied by the employees at Dworshak National Fish Hatchery. Have a safe and happy Thanksgiving.

Catch and Release

We are in the thick of Clearwater B-Run steelhead return. Fishers are lining the banks of the Clearwater River from Lewiston east to Kamiah presenting every imaginable variety of fly, lure, or jig trying to catch the “Steelie” of their life. It is fun to watch people from all walks of life come together to fish; exchanging stories about the “one that got away,” and sharing in the excitement when someone’s line goes tight and their reel starts zinging. Making sure there are stories to tell and fish to show off are some of the many reasons I love my job. Seeing a child bring in his or her first fish is an affirmation for what the National Fish Hatchery System does: working with others to conserve, protect and enhance fish, wildlife, and plants and their habitats for the continuing benefit of the American people.



An angler lands a respectable steelehad. / USFWS



In an effort to conserve and enhance the Clearwater River B-run, the Idaho Fishery Resource Office is utilizing a mark re-capture strategy to determine if early returning B-run steelhead remain in the area throughout the run. This is being accomplished by PIT tagging early returning steelhead, releasing them to the river, and tracking where they go. The concern is that the earlier returning fish are in the river longer and therefor are exposed to more fishing and harvesting pressure. Dworshak National Fish Hatchery strives to get even representation throughout the B-run by collecting adult steelhead as they begin arriving in October. Collections continue throughout the run, which typically ends in April. The consequence of this impressively long run time is an equally long holding time for early run fish. If the PIT tagged fish return to the Hatchery later in the run then we will have a good idea that early run steelhead are staying near the hatchery and we can achieve the run representation we are looking for without opening our ladder early and holding fish for several months.

B-run steelhead making the final leap up the fish ladder at
Dworshak National Fish Hatchery. / USFWS

Other valuable information is being gathered from these PIT tagged adults. PIT tag detection sites located along the South Fork Clearwater River and Lolo Creek have recorded some of the tagged fish indicating the fish will stray to other areas. There have also been a small number of fish detected at Lower Granite Dam indicating kelts (adult steelhead that spawn and return to the ocean) returning to the ocean. Everything that is learned from this project will further our understanding of this incredible species and will enable biologists to make sound management decisions. In turn, the remarkable steelhead fishing on the Clearwater River will continue, the even more remarkable fishing stories will be told, and “the one that got away” will never be forgotten.





USFWS employees PIT tag an adult female
 steelhead that recently returned to the Hatchery
 in the early part of the B-run. / USFWS



PIT tags give unique identification number
to the fish allowing them to be tracked wherever
there is a detection site. / USFWS



"There is certainly something in fishing that tends to produce a gentleness of spirit, a pure serenity of mind."

~by Washington Irving~