The Pemberton Wildlife Association (PWA) is a volunteer-based, not-for-profit organization that was founded in 1962. They are dedicated to promoting conservation, preservation and enhancement of wildlife and outdoor recreational resources. Over the decades, the PWA has been actively involved in important projects such as wildlife and fish population assessment, enhancement and habitat restoration, education, land conservancy, support for safe sportsmanship and recreational access. They work with volunteers, other community groups, Líl̓wat Nation, all levels of government, and the general public to further their purpose.
The PWA wanted to present a series of posts about one of the most incredible components of the watershed, Pacific Salmon.
In this first one, I will introduce the species and stock numbers and the last will be more generally about the state of Salmon in the Fraser River watershed and highlight some of the ongoing research underway to understand the declines.
First, we are going to be speaking generally about the Lillooet River watershed which includes all major tributaries such as Birkenhead River, Green River, Ryan River, Miller Creek, South Creek, North Creek and Meager Creek. The Lillooet River flows into the Fraser River through the Harrison River.
Here is a map of the larger sub-basins of the watershed:
In the watershed, all five species of salmon can be found, but only Coho, Chinook, and Sockeye have significant runs. We wanted to introduce these three species to you and if you know them well already, we wanted to give you an update on their status with the information we have available.
All Pacific Salmon have two parts to their life cycle: freshwater and saltwater. The salmon spawn in the fall and the eggs incubate in underwater gravel nests called redds. The eggs stay in the gravel until small fry emerge in spring, around April. This is why it is important to keep dogs and yourselves out of spawning streams for the entire winter. Once the fry emerge, some species head to the ocean immediately, and some stick around in the watershed for more than a year before heading out. Salmon then spend their adult life in the ocean, anywhere about 1 year (Pink Salmon) to as long as 8 years (Chinook). Some Salmon take long journeys, heading up the coast to Alaska before returning, and some stay in closer BC waters. They all return to their natal freshwater stream where they were born to spawn again. As you can imagine, this massive life cycle comes with a range of threats to both fish and their habitat.
Here is a representation of the Coho life cycle in the River of Humble Beginnings, near South Creek. We will introduce Coho first!
Coho Salmon spawn late into the fall and early winter, so if you have seen a Salmon after Halloween, it was a Coho. The last one I spotted was on January 4, 2021 at the inlet to One Mile Lake. With all its challenges, 2020 has been a near perfect Coho spawning season, with heavy rains coming before Halloween and continuing until after the new year with no extended periods of deep freeze temperatures the reduce the streams to solid barriers of ice. Coho like groundwater fed springs and will move as high as possible into their respective rivers, streams and even the occasional drainage ditch. Some of the males can get quite large, like this one from South Creek:
(And no, I didn’t snowshoe up the entire creek. Whenever I am doing spawning surveys, I am very careful where I stepping, making sure to steer clear of redds and I just stepped in to provide a scale for this photo😊).
Líl̓wat Nation has a significant annual stock assessment program for each of the three species and 2020 they counted 1072 coho spawning in the Birkenhead River. This is a pretty good return.
Based on other assessments and community observations around the watershed coho had a pretty good run overall in 2020. For example, Alena Creek at the toe of Capricorn Creek landslide had the largest total count recorded since 2010 and the second highest number of fish observed in a single trip (173). Below is a picture of some coho doing what they do at Alena Creek.
The largest salmon in the watershed are the Chinook Salmon, aka Spring Salmon, aka King Salmon if you are from Washington. In this watershed, they move into their spawning streams early in the spring, and hang out until conditions are perfect for spawning, around the end of summer. According to DFO, “Birkenhead Chinook are one of the most genetically distinctive Fraser Chinook populations and have one the lowest levels of polymorphism and heterozygosity”, which is a fancy way to say that they are a really special version of the Fraser River stock. They are the earliest returning, one of the largest-bodied and have been shown migrate further north into Alaskan waters than other Fraser Chinook. The height of the spawn is usually around September 12. They prefer larger rivers and will not use the much smaller streams like Coho. The Birkenhead River is one of the most important spawning rivers in the watershed. There are reports of Chinook throughout the Lillooet River and I have personally trapped juvenile Chinook upstream of North Creek, but I could not say where exactly they are spawning because the river is very large and very turbid (cloudy) for most of the time Chinook are active.
Because the Birkenhead Chinook are genetically unique, and an isolated population, DFO also says “small populations are especially vulnerable to threats such as those posed by fisheries exploitation, climate change, and habitat alteration”. And this threat applies to all salmonid species in the watershed. Salmon have such a complex life cycle, spawning in freshwater and spending the majority of their lives in the ocean, only to return to their natal streams. This exposes them to a vast number of risks, and an evolutionary strategy is to have lots of babies. Each salmon will lay between 2000-5000 eggs, yet we see returns of 1%.
In 2020, approximately 192 Chinook were observed by Líl̓wat Nation technicians in partnership with DFO stock assessment. Generally, Chinook numbers are less than 1000/year, but 2005-2007 and 2010 all saw returns above 1000. Here is a graph showing escapement numbers from 1990-2018:
Here is a photo of Birkenhead Chinook doing their thing during spawning season.
Finally, Sockeye Salmon are the species that people who don’t know anything about fish think of when you say the word ‘salmon’. When spawning, they are bright red with a shiny green head. They can return in huge numbers to their natal streams to spawn, though that is becoming a bit of a rarity these days. Lilwat Nation in conjunction with DFO has been doing spawning surveys for Sockeye for a very long time. The table below shows the size of the run over the period of assessment. You can see there is quite a bit of variability and this is related to life cycle, where you can expect sockeye to be returning to spawn as 3-5 year old fish, with the majority of them in 4-5 year old range, hence a large run every ~5 years. Unfortunately, following the last big run in 2011, the subsequent years have seen some of the lowest returns ever, with 2019 at an all time low of ~2900 sockeye, followed closely by 2020 at 5263. These are alarming numbers, despite large periodic returns seen in the last 20 years. We are so fortunate that Líl̓wat Nation is so invested in keeping good records and working proactively to protect habitat of these returns because drastic action is required in the near term if numbers continue to plummet.
There are so many factors affecting salmon survival, but that is the subject of another blog post coming shortly!
Here is a quintessential Birkenhead Sockeye pic: