Saturday morning saw an estimated 50 students, teachers, advisors and local salmon boosters (all part of the Edmonds Stream Team) pitching in at Edmonds’ Willow Creek Fish Hatchery to fill incubation boxes with more than 5,000 coho salmon eggs.
The boxes will be planted in Shell, Willow and Shellabarger Creeks. There,the hatchlings will grow and eventually migrate downstream to Puget Sound, where they will mature. The young salmon imprint on the unique chemical signature of the water in the stream where they hatched. Returning to spawn, they literally sniff out and follow this chemical signature right back to where they hatched in local streams.
The Edmonds Stream Team had its beginnings more than seven years ago as the Edmonds-Woodway High School Students Saving Salmon Club. It has now grown to include students and faculty advisors from Meadowdale High School.
“We now have 87 students on the Stream Team,” said local fish biologist, team advisor and passionate salmon booster Joe Scordino. “It’s been fantastic adding Meadowdale to the effort – with more students we can do so much more to help restore, enhance and foster salmon runs in our local streams.”
Saturday’s effort involved assembling incubation trays, each of which holds 200 salmon eggs in individual chambers. The assembled trays filled with eggs are kept at the hatchery in tubs of moving, oxygenated water drawn from Willow Creek until they are ready to be placed in the streams.
“We keep them in the best conditions possible before placing them,” explained Scordino. “This gives them the best chance of survival.”
On placement day, the trays are linked together in groups of three and placed directly in the stream in repurposed milk crates. The crates are secured to the streambed and protected with a placement of upstream rocks to minimize intrusion of silt into the egg chambers, thus ensuring the steady flow of water necessary for maximum survival of the eggs.
“We’ve been using these hatch boxes for several years now,” explained Scordino. “At first we had some issues with sand and silt clogging them up, but we’ve refined our technique and we think we’ve got that licked.”
The hatch boxes and their egg chambers are designed not only to maximize survival of the eggs, but the hatchlings as well.
“When the eggs hatch, the yolk sac remains attached to the young alevin (hatchling),” explained Scordino. “The holes into the individual hatch box chambers are small enough that the alevin can’t get out until the yolk sac is completely absorbed, which is two weeks or so after hatching. Remaining in the box gives them additional protection and the attached yolk sac provides all the food they need. As soon as the sac is absorbed, they squeeze out through the hole in the hatch box and start feeding on their own. This not only protects the egg, but after hatching protects the young alevin.”
Two hatch boxes were planted in Willow Creek on Saturday morning. The team planned to meet again on Sunday to plant the remaining five in Shell and Shellabarger Creeks.
Planting the hatch boxes in Willow Creek involves something of a leap of faith by the Stream Team, hinging on the planned daylighting of Willow Creek.
Presently Willow Creek drains through the Edmonds Marsh, which connects to Puget Sound via a 1,600-foot underground pipe. While the pipe poses no barrier to young salmon moving from Willow Creek into Puget Sound, returning salmon cannot migrate back up the pipe to spawn. (The Willow Creek daylighting effort has been in process for almost a decade. Learn more about it in these My Edmonds News stories from 2013 and 2019)
“We’re crossing our fingers that three years from now when these fish return, they’ll have a direct path back upstream,” said Scordino.
— Story and photos by Larry Vogel