Boom or Bust by Lucas Holmgren
Ocean-Run Salmon | The Most Conditional Fishery There Is
There are a million ways to die as a salmon. Survival of the fittest only begins to describe the life-cycle that these fish experience on a yearly basis. Emerging from the gravel, navigating freshwater streams and crossing tidal estuaries into the open ocean, instinct drives every move. Arriving fat and fresh, their years of ocean feeding brings one of the most exciting and fulfilling fisheries known to man.
If every salmon egg that was laid turned into an adult fish, our rivers would be so full you could walk on them from tidewater to headwater. With female salmon laying anywhere from 1,000 to 10,000 eggs the potential in a perfect world is massive...but we live in a far from perfect world.
The spawning process all depends on the number of adults that have arrived on the spawning grounds. This number of fish comes full circle from the cycle of events we will discuss:
The resilience of Pacific Salmon starts with their incredible potential. Every successful redd (“nest”) produces fry in anywhere from 1 - 19% of the egg count on average. This initial cut to the ranks is the first of many. Some redds are not successful being wiped out by disturbance or unprecedented flows, others produce fry that start the foray into survival.
As these fry emerge they learn to navigate their newfound habitat, but it is not always a friendly place. Depending on conditions and time of year, they can be met with a temperature or river flow challenges. Low and warm flows may leave fry vulnerable, stranded or over-heated. High flows may wipe out redds or displace fry from safe rearing areas.
Freshwater habitat can make or break a newfound salmon population. Highly developed areas are often the hardest on salmon populations. Construction and activities that remove trees, reduce structure and hasten flow can create a feeding frenzy for predators and remove much needed oxygen and nutrients from the water. Water flow can be hugely disrupted by development and create a stagnant or volatile stream. Natural, shaded streams with lots of cover, structure and cold water protect salmon fry and create a strong population of well-prepared fry ready for deployment.
For the fry that make it this far in the process they now have the predicament of navigating from freshwater stream to estuary. Different species of salmon leave for the ocean at different times. Chum salmon are quick to depart making them less susceptible to in-stream failings but more susceptible to estuary dangers. Every species has its challenges which is why some years we enjoy a great run of “x” and a bad run of “x” salmon. When salmon mature, their instincts kick in and they turn towards the mighty Pacific Ocean in search of a better food source.
If freshwater challenges were the last thing salmon had to worry about, we would still have more fish coming back each than we could imagine, but for salmon, the journey has only begun.
Salmon, being a nutrient and protein filled fish, are a rewarding meal for predators. Sea Lions are lethal to returning adult salmon, destroying populations of salmon, steelhead and sturgeon wherever possible. Juvenile salmon are prime targets for birds like cormorants which enjoy snack size salmon en route to the ocean. Fish, birds, sea lions, squid and other predators can stop a salmon dead in its tracks when the opportunity is presented. If salmon have the extraordinary luck of making it out of their freshwater environments into the salty expanse of the ocean, they have now found what is likely the most variable of environments, the ocean.
Undiscovered and unpredictable, the ocean is the feeding grounds for hungry salmon. Every year the currents, temperatures and feed change. One year the temperatures may aid in the survival of the salmon, the currents may bring feed directly into their path...other years things don’t work out so well.
This stage is perhaps the most undocumented. Certain runs and species tend to travel towards specific Ocean regions, but there is still major variety in their migration routes.
This is the stage that can make or break an entire region of salmon. One could blame the circumstances of a single river for a bad return if that river was the only one in the region with low numbers, but when every single river in a large varied region has a bad year, the Ocean is likely the defining factor.
The Ocean can offer up salmon runs of incredible sizes or slash a population into oblivion.
Instinct drives salmon to their natal streams. It’s in their blood, in their makeup, it’s simply nature. Fish that survive the ardous journey turn to their streams in pursuit of a spawning mate. This instinctual drive brings salmon to navigate their ocean currents and head for home. This part of the process has a whole new set of challenges.
Just as they passed journeyed out of the stream into the open ocean, the salmon must charge headlong back into the rivers from whence they came.
The river can immediately become a limiting factor for adult salmon survival. Some years, and notably in the state of California, massive drought and warm water temperature can put a dent in salmon replenishment.
Temperatures can keep salmon from migrating upstream, choosing instead to stay in tidal areas or lower holes within a watershed. This can limit spawning potential if there is not a water event to encourage upstream movement. Still, salmon are known to move forward despite the odds, intent on finding a place to build a “redd” (nest.) At this point, adult salmon are very unprotected. Salmon in low clear flows can be easily disturbed.
If the river has suitable temperatures and flows, salmon may infiltrate the watershed easier, but they’ve still got to protect themselves from a few major threats. Nets capture salmon whether they are currently operated or one of many ‘derelict’ left-behind nets.
Sea lions have proven to be absolutely devastating to fish populations. The Columbia & Willamette Rivers have been under seige by an increasing number of sea lions that are picking off any salmon, steelhead and sturgeon that cannot escape. Waterfalls and dams that stop or slow salmon migration are a buffet table for greedy sea lions.
For all that a salmon endures, it can all be cut short just shy of the spawning bed.
A few salmon still make it.
When the last egg has been laid and the redd is fertilized, the salmon may finally spend it last days without purpose. Up until this point, salmon have been dutifully bound by their instincts and drive to reproduce. Now, with the journey complete, they begin to meander from their redds, losing vision and skin, showing signs of life and then fading into nothingness.
And yet, emerging fry and the streams they occupy benefit from the carcasses of their parents. The next generation emerges, a testament to a new day, and another chance at a salmon run of epic proportions.
“Old salmon never die...they just, fade away…”
Disclaimer : I am not a forester, scientist or marine biologist. I am simply a writer jotting down the factors I have found from asking questions, reading articles and watching videos on the subject.