When one hears about farming fish, you think about the net-pen rearing of Atlantic salmon or trout — which we know pose threats to our resident and migratory salmon. Cramming thousands of salmon into a small pen creates a continuous, concentrated plume of fish excrement for the local environment. This plume pollutes the environment, and since many pens are built in inlets to reduce wave action, the effluent concentrates in these areas.
The collapse of the net pens off Cyprus Island in 2017, moreover, demonstrated how the largest net pen operators can fail to comply with existing regulations, which should cause all of us to closely reconsider this type of farming.
Thankfully, Canada is addressing these problems by phasing out pen-rearing of salmonids (including salmon and trout) and encouraging a whole new form of aquaculture: Recirculating Aquaculture Systems (RAS). RAS are land-based, closed systems which eliminate the problems and risks of net pens. The fish are raised in tanks, and the water goes through several stages of treatment before recycling back into the closed system. No effluents are released, and potential disease is contained.
Last year, Canada’s Prime Minister Justin Trudeau committed to a transition from net pens in coastal waters to RAS systems by 2025. British Columbia is carrying out this national policy locally, detailed in this excellent article in RASTech Magazine: Canada Begins Transition for Salmon Net Pen Farms. Check it out!
Sewage plants release 26 million pounds of nitrogen in Puget Sound each year, according to the Department of Ecology. This is a serious problem for salmon, orcas, and the Puget Sound food web.
If you’re a gardener, you know that nitrogen is a key component in manure, infusing our vegetable gardens with explosive harvest potential. Likewise, in water, concentrated nitrogen fuels explosive growth (blooms) of phytoplankton (algae) — particularly from spring to early fall when there is more sunshine and the temperatures are warmer. As algae blooms use up the nutrients in the surface water, their growth slows and they eventually die. Their cells sink to the ocean floor, where they are decomposed by bacteria, which consume oxygen in the water (and release CO2). Large algae bloom die-off’s can create oxygen-depleted dead zones where aquatic life cannot survive. Even when they don’t create dead zones, the CO2 released by the bacteria during decomposition mixes with H20, increasing acidity, which impacts shellfish. No matter how you look at it, these blooms are bad for aquatic ecosystems, and the 26 million pounds of nitrogen introduced into the Puget Sound from wastewater treatment plants creates a devastating problem for the food web, all the way up to salmon and orcas.
Our wastewater treatment plants fall short. The article points out that Washington state treatment plants are behind the times. Requirements for upgrades were last made in the 1980’s, where they adopted technology developed in the early 20th century. Most treatment plants in Washington today simply do not remove nitrogen.
The article posted on Crosscut.com presents more details on the current debate on how we can meet Clean Water Act standards for dissolved oxygen for the Puget Sound, but where there is no debate is that nitrogen from human activity is to blame. We encourage you to read the article to learn more about the timeline, costs and interim measures associated with upgrading our wastewater treatment plants throughout the Puget Sound.
Our coho have a perilous journey from the Chittenden Locks to the Issaquah Salmon Hatchery — and researchers at the University of Washington, Tacoma and Washington State University, Puyallup have identified the chemical responsible for mass pre-spawning deaths of adult returning coho in our urban streams.
According to the article, 1% of adult returning coho typically die before spawning. But in these mass death events, anywhere from 40% to 90% perish in the most affected streams.
The article highlights an amazing piece of research and we encourage you to read it. Investigating thousands of potentially lethal pollutants, the research team narrowed it down to just one elusive culprit: 6PPD-quinone, a fish-toxic compound generated by the breakdown of automobile tire particulate. In other words, a chemical preservative found in tire dust is broken down by ozone, creating this highly toxic 6PPD-quinone. This is a remarkable feat of scientific research and determination.
Interestingly, this study suggests that 6PPD-quinone specifically, mortally impacts coho — and not other species of salmon.
It is worth considering just how quickly this chemical affects adult returning coho as they return to their home streams.
Researchers call for the development of a “green” chemical alternative to the offending tire preservative. While we agree that better treatment and management of stormwater runoff would also be ideal and should be pursued, it is challenging to implement.
We encourage you to read the article and enjoy their embedded, instructive videos.
Thank you to all of our wonderful docent volunteers who helped make our small group tours possible this season! To those of you who joined us, we were delighted to be able to share the salmon season with you, and we look forward to seeing many more of you next year! Here’s to a good new year full of cool, flowing water, eggs, alevins, frys, fingerlings, smolts and returning adults! Keep ’em coming home!
Your Friends at FISH
Gallery: 2020 Small Group Tours
Issaquah hatchery staff and FISH volunteers harvested about 258,000 eggs during the first coho spawning of the 2020 season on Tuesday, Oct. 27. Eggs and milt were collected from 119 spawning pairs. The egg take represents about one quarter of the hatchery goal of 1 million eggs for the season. With a healthy return of fish so far this year, the hatchery was also able to release 419 coho upstream of the hatchery to continue farther up Issaquah Creek and spawn naturally. In addition, three late-arrival chinook were released upstream, and one rainbow trout that followed the salmon into the hatchery holding pond was returned to the wild as well. Coho spawning will continue for the next two to three weeks.
Stay tuned for more updates!
Almost 2,500 kokanee fry bid a fond farewell to the Issaquah Salmon Hatchery on Oct. 26 as they started their new journey to Lake Sammamish. The lake’s threatened kokanee population, whose numbers have dwindled to just a few hundred in recent years, will get a boost from this new batch of fry which were incubated and raised at the Issaquah hatchery from eggs collected in late 2019.
The hatchery rearing program is part of the recovery efforts of the Kokanee Work Group, an alliance of federal, state, county and local agencies, tribes and non-profit organizations dedicated to ensuring the survival of Lake Sammamish’s “little red fish.” The effort has conducted annual fry release programs, including educational components for local students, for the last 10 years to raise awareness about the plight of these native fish, threatened by environmental challenges due to urbanization. This year, with the hatchery closed and students attending virtual classes, a public celebration was not possible.
In the past, fry were released at very early stages of development, when they were only about one inch long. In this second year, the hatchery retained and fed the fry for a longer period, until they reached 5-6 inches in length, continuing an experiment to determine if larger size, and cooler waters, help to prevent predation by other fish in the lake that may be depleting the population.
Officials from the Washington Department of Fish and Wildlife and the King County Department of Natural Resources used buckets to transport the squirming kokanee fry from the hatchery incubation building into a waiting truck outfitted with a large covered tub of water. The eggs were collected from fish in Lewis Creek, at the south end of Lake Sammamish, so their progeny were transported back to Lewis Creek for release, and they were expected to migrate quickly to Lake Sammamish. There, they will grow and mature before returning to the stream to spawn at 3 or 4 years old. Bon voyage, little kokanee!