#fishtales

I got tired of having to scrounge up pictures for Nereid's tail and jewelry, so I made a reference sheet.

Blogger’s note: It may look like a quiet winter wonderland but cold weather doesn’t stop conservation at Leavenworth National Fish Hatchery in Leavenworth, Washington. Julia Pinnix, our visitor services specialist at the facility, takes us behind the scene in this installment of “Fish Tales” which appeared recently in The Wenatchee World. All photos credit US Fish & Wildlife Service.

Hatcheries in winter are just as busy as in summer, but in different ways. At Leavenworth National Fish Hatchery (LNFH), the eggs of August have transformed, growing through the alevin stage, when they have yolk sacs on their bellies and can’t swim well, into tiny fry. By the first week of March, 1.2 million of these wee fish will fill 124 tanks in the nursery, and will need to be fed up to seven times a day. It’s chilly in the unheated space, especially with the moving water generating a draft, so I have to wear a coat to spend much time observing.

What’s the worst thing about working at a hatchery in winter? “Monitoring water flows and breaking ice for several nights in a row is the least desirable part about winter conditions, but keeping the water flowing is critical, and most rewarding after a cold snap,” is Craig Thomas’s answer. He is the assistant manager at LNFH. Fish need water the way humans need oxygen. A couple of hours without fresh water pumping into the ponds, and they will die. So a freeze-up of the pipes or ice clogging the intake is a full-on emergency. On January 16 and 20, ice on the Entiat River broke up and clogged the intake system for Entiat National Fish Hatchery. Staff spent hours clearing ice and keeping water flowing to their summer Chinook.

Photo: Ice accumulates around the intake system.

Fish are cold-blooded, so as the water chills, everything slows down: metabolism, heart rate, movement. “We feed them about once a week right now, whenever the ice opens up,” says Biological Science Technician Darren Hemmer from LNFH. Sara Reese, assistant manager at Winthrop National Fish Hatchery (WNFH), reported, “Cold temperatures during the middle of January brought river temperatures to 32 F...brr! There was no fish feeding for about a week and a half during this, as the raceways were 37 F (this is due to a combination of river and ground water).” Craig noted, “We generally don't feed when the water is below 36 degrees. Even then it is a reduced ration. The fish have a difficult time processing the food during cold temps, nor do they require much food.”