In a recent instagram post by fisheries biologist John R. McMillan (@rainforest_steel), the wild salmonid crusader emphasized a little-known necessity for a healthy salmon river. Check out the full text below.
“The four H’s of salmon recovery are: Hatcheries, Hydropower, Harvest, and Habitat. Of those, habitat is most often proffered as the main factor limiting salmon recovery. Of course, if you live in the Snake River or pretty much anywhere in Central/Southern California it can be argued that hydropower has been just as bad, even worse. Regardless, my point is that nearly all of us agree that freshwater habitat is critical to the production of fish and the sustainability of our fisheries. It is fundamental. That is why we have spent billions of dollars trying to restore and reconnect the fish’s habitat.
However, habitat is not just stream flow, large wood, and floodplains. There is another component. A factor so clearly understood to be important that it is hard to imagine why it continues to collect dust in the big box of potential salmon recovery tools – because the notion is as old as human and salmon have interacted. What is it? Hint: You smell it before you see it. Food. Salmon eggs and rotting flesh. Served up fresh each fall. In case you missed it, salmon subsidize the food supply, and outside of having water, nothing is as important to growth as food. So, just how important are salmon in the scheme of things? Well, research by M. Nelson and J. Reynolds at Simon Fraser University looked at 17 streams in BC and found chum salmon density was the most consistently important factor correlated with juvenile coho body size. More important than pink salmon and the density of the juvenile coho. Even more important than habitat factors like pool volume and canopy cover. Sure, the coho still need the basics: cold water, pools, some cover and access to the ocean. A coho studio apt, if you will. But, metaphorically, the chum are basically the breast milk of the ocean. Nursing each little salmon until they are large enough to hop on the bus and head to the big blue college of hard knocks, where the vast majority of little cuties will die – per Blondie – One way, or Another.”
Thanks for the maternal imagery, John. If you’re interested in more micro-lessons about salmon & steelhead biology, make sure to follow him @rainforest_steel.
If you’re interested the study mentioned above, you can find a jargon-laden report here.