Many things have contributed to the great decrease in salmon populations up and down the coast. There are plenty of arguments to suggest we should sit idly by with our hands tied. Many believe we understand so little about the causes that it’s a waste of time and money to try to stop it, or maybe they just give up thinking its things we can’t help like loss of habitat, or climate change. Others have been lulled to sleep by being handed yearly batches of hatchery fish. Many simply believe salmon are resilient enough that if we leave them alone they will bounce back.
However there are two scientifically proven causes that have destroyed most of our fisheries up and down the coast. Two tangible issues that can very easily be focused on and changed to help preserve what is left of our coastal fish. Commercial fishings high catch rate of mixed stocks and hatchery fish.
Lets keep it simple and,
1) minimize impacts of hatchery fish on wild fish
2) Switch to a commercial fishing style where method or fishing gear allows healthy stocks to be targeted, while minimizing or avoiding the harvest of stocks of concern, or one that allows release of stocks of concern unharmed.
Not all fish are created equally in the world, and it has been proven over and over again that wild fish are genetically superior. The reason for this of course is the genetic diversity a wild fish has. What has become quite apparent is the great difficulty of rehabilitating the genetic structure of a domesticated man made fish.
Slowly trickling into mainstream opinion is that there is a very serious need to conserve this diversity in the wild. In fact the survival of wild salmon depends ultimately on genetic diversity. Fish are so distinct to each local stream condition found in the spawning grounds. I don’t think anyone can be surprised to find out captive-reared fish are genetically inferior to wild ones in natural environments as a consequence of domestication, and that it negatively effects the recovery of wild populations.
We are lucky enough to be fishing some of BC’s last runs of wild salmon, however up to 75% of rivers in our area are severely depressed.
A lot of these systems up here are pretty barren. Nutrient poor rivers with very little aquatic and terrestrial food life. Spawning salmon were the life blood that moved nutrients from the ocean to the stream and forest. The nitrogen and the phosphorous delivered to the rivers and river banks through predation and rotting carcasses have always been far more crucial in our northern rivers to the wildlife and ecosystems that surround them. Today less than half of the salmon biomass that once returned to BC rivers still remains. This in turn exaggerates how barren these rivers are and makes for off the charts low rearing densities.
As fewer and fewer salmon return annually, fewer and fewer nutrients are brought into the river, and it slowly starts to dry out all life. It also triggers reduction in species that eat salmon, killer whales, bears, wolves, eagles. The truth is the importance of salmon to the ecosystem has never been factored into DFO catch levels, and harvest rates are always set to meet what they consider acceptable levels to not kill off a run. Little consideration for ecosystems or predators is ever given.
The most common solution to this has been to go towards hatchery fish, which in turn helps to diminish genetic diversity, promotes more mixed-stock fisheries. In the end it promotes more commercial fishing, and causes hatchery fish to breed with wild fish creating a domesticated gene pool. It’s an endless cycle of failure we are perpetually stuck in.
Over-fishing has pushed the number of a lot of our coastal stocks bellow sustainable levels. Most of this can be blamed on mixed stock fisheries catching non target species. Fisheries currently catch far more fish than the oceans can produce. Almost every major fishery in the world has seen its catch drop despite increasingly intense efforts, and many fisheries have collapsed entirely.