Earth Friendly: Turn fish into fertilizer
By Meridith Byrd
Some of you may know that in my other life, I am a marine biologist. So, when I came across a news article about turning lemons into lemonade, or rather dead fish into fertilizer, I could not pass it up.
Earlier this month, a marina in Redondo Beach, Calif., was the site of a massive fish die-off that was comprised mostly of sardines. An estimated 140 tons of fish were found floating at the surface and piled along the sea floor in a blanket up to 24-inches thick. Birds and sea lions were feasting on the fish as if they were at an all-you-can-eat buffet.
Biologists first believed that the fish came into the King Harbor marina either because of inclement weather, or after being chased there by predators. It was later determined that the fish tissues contained high concentrations of a neurotoxin called domoic acid, the result of an algal bloom that was occurring nearby. The domoic acid caused the fish to swim erratically and concentrate in the marina. Once crowded into such a small area, there was not enough oxygen in the water to sustain all the fish, causing them to suffocate.
City officials had to come up with an idea to remove the millions of dead fish. Vacuum trucks were used to suck the fish off the sea floor while crews scooped and collected the dead fish floating at the surface. While the first plan called for the fish to be taken to the city landfill, it was ultimately decided to take the fish to an American Organics composting facility in nearby Victorville, where the fish will be composted and processed into fertilizer. Biologists will monitor the domoic acid levels as the fish decompose, though they expect it to degrade quickly during the composting process.
Any seasoned gardener can tell you that turning fish into fertilizer is nothing new. Fish meal, which can be made from the entire fish or just the bones and organs, is a slow-release fertilizer especially beneficial for leafy plants. A good source of both nitrogen and phosphorous, fish meal conditions the soil and encourages root growth.
Fish emulsion is made from the byproducts of fish meal and fish oil production. First, the oils are removed from the cooked fish and will be used in cosmetics and paints. Next, the proteins are extracted and dried for animal feed. Finally, the remaining liquid is concentrated and sold as fertilizer. Fish emulsion can result in long-lasting, vibrant flowers. While other fertilizers break down slowly in cooler months, fish emulsion breaks down at a steady rate.
What a strange, but interesting example of recycling. When life hands you lemons you are encouraged to make lemonade. When the King Harbor Marina in Redondo Beach was filled with dead fish, officials took the opportunity to make fertilizer.
Meridith Byrd is a marine biologist and invites readers to contact her at firstname.lastname@example.org.