Lesson 3: Water from the
Earth Team
Lesson 3 will take 2 hours to complete and be graded by a multiple-choice quiz.
In this lesson:
• Learn more about late spawning Sockeye, Chum, and Coho
• Identify groundwater-fed channels
• Habitat restoration techniques specific to groundwater channels
• Identify situations where restoration work can do more harm than good
Meet the Water from the Earth Team
Lesson 1 was all about Chinook salmon; but within Chinook populations, there is so much variability that they could almost be considered their own species – so they are the Tyee Team.
The Clean Stream Team in Lesson 2 covered Pink salmon and some forms of both Sockeye and Chum salmon.
Today we are going to focus on the species that use groundwater-type habitats: Sockeye, Chum, Coho. This is the Waters from the Earth Team.
This group of species spawns late in the year
You’ll remember from Lesson 2 that late-season spawning requires warmer waters. This bundle of species includes:
Sockeye salmon that spawn mid-November-January.
Chum salmon that spawn mid-November-January.
Coho salmon who spawn December-March.
Heated by the earth itself, upwelling groundwaters are the warmest waters available to salmon. These magic waters do not freeze even on the coldest winter days.
Unique spawning grounds require special consideration
There are many special areas in S’ólh Téméxw that feature groundwater side channels.
2 examples are:
Ashlu Creek (from Lesson 2)
Mamquam River
This is a man-made, groundwater-fed channel constructed on the Mamquam River.
If you build it, they will come. Here we see Mamquam Channel is filled with spawning chum salmon.
Habitat restoration technique: Groundwater channels
Groundwater channels are simple to construct: they involve simply digging a big ditch and allowing water to flow into it. The complicated part is determining where to construct these channels – good spots to dig, where surface aquifers already exist – are rare and hard to find.
Late spawning chum salmon are one of the best clues that a surface aquifer is nearby.
Groundwater channels need to be near a river, but far enough away to offer protection from flooding for salmon eggs;
They are dug approximately 1.5m below the water table;
Water upwells through the gravel at the base of the channel and creates a steady flowings stream, perfect for this Water from the Earth Team of salmon.
So off we go let’s build a groundwater channel together.
Step 1: Clear trees and vegetation, forming a right of way for the channel
Step 2: Remove fine sediments; any silt and sand sitting on top of the buried gravel
Step 3: Construct drainage ditch down one side. This will keep the work site dry, and act as a ‘test ditch’ for your future channel
Optional watching
A classic 1988 video describing the design and construction of the Jacks Slough groundwater channel on the Indian River in Burrard Inlet, Vancouver, BC, Canada.
The story of Hicks Creek Coho
Hicks Creek has some of the latest timed spawning Coho in the whole Fraser River watershed.
They have been spotted spawning as late as April, but not just anywhere…
Only in two, clear warm pools of water that bubble out of the earth.
Optional reading
DFO Summary of what we know about coho salmon use of groundwater channels in B.C.
Large Conservation Areas for these species suggest that these populations share genes and that there is movement of fish between watersheds.
Eg:. Metro Vancouver lost their chum salmon a long time ago. Over the last 30 years, they have been repopulated by conservation hatcheries that use eggs from within the conservation unit (Alouette River and Kanaka Creek.)
Sockeye have small conservation units – much like their Chinook cousins in Lesson 1.
Eg: Harrison, Pitt River, Cultus Lake Sockeye are each their own C.U.
Sockeye salmon commonly are found spawning on groundwater upwelling areas.
Often, sockeye spawning occurs deep under the lake surface (50m or more!) where the springs seep into the lake. This presents a challenge for habitat restoration efforts.
Optional Reading
Paper on Alouette Lake Sockeye in S'ohl Te’m:e'xw"
Coho salmon: Onchorhynchus kisutch
Sockeye salmon: Oncorhynchus nerka
Groundwater upwelling areas are sometimes closer to the surface in shallower water, or found along beaches where the water flows out of nearby gravel banks. This makes restoration work on spawning habitat much easier.
Kalum Lake restoration work
This sockeye run in the Skeena River watershed was down to 1000 spawners in the 1980s – extensive logging and overfishing likely to blame
Locals had seen a few sockeye spawning at the base of a glacial deposited gravel hill on the edge of the lake Kalum Lake. This piqued the interest of the Salmon Enhancement team at DFO.
37 years later, hundreds and some years thousands of sockeye can be found spawning here.
Optional reading
A project being to be considered for the future: Cultus Lake sockeye
Similar to at Hicks Creek, a steep mountain stream has created a large alluvial delta that pushes out into Cultus Lake – this delta is now the Cultus Lake Provincial Park.
If you walk along the beaches of the southern portion of this delta in early December, you might get lucky and see a few endangered sockeye salmon spawning there. They seek out warm groundwater seeps and inflows.
Many of the places where groundwater flows into the lake are very sandy and not suitable for spawning sockeye, and here lies the opportunity for salmon habitat restoration.
If the groundwater flowing into unsuitable locations could be collected in a drainage gallery, would sockeye salmon use it and do well? We won’t know until it’s tried.
An uncommon preference
The third population of groundwater spawning sockeye salmon in S'ohl Te’m:e’xw is the threatened Widgeon River-Type sockeye salmon.
This population does not rear in a lake before heading out to the ocean; a very uncommon trait.
They spawn in a small area that is fed with upwelling groundwater flowing out of a rock slide deposit in the floodplain of the Pitt River.
Optional reading
If you want to learn more about the status of this population and the previously discussed Cultus Lake sockeye you may find this COSEWIC report interesting.
Take notice of the angular gravel in this spawning habitat. It also has a relatively high percentage of fine sediment and a very shallow depth of water over the gravel.
This is an area under tidal influence, so these sockeye wait until high tide to come in and spawn.
The Widgeon sockeye must move through dense stands of reed canary grass in a tidal marsh habitat. In some places, they have cleared significant patches of usable spawning gravels.
This is a post-spawning Widgeon sockeye salmon; note the subdued colours and small body size.
You’ve reached the end of Lesson 3.
Remember, think once, think again and then again before undertaking habitat restoration work. Only time will tell if you did the right thing.
Like the Cultus Lake sockeye discussion, there appear to be sites suitable for the construction of upwelling spawning ponds. However, any disturbance of this vulnerable area could bring unintended consequences – so no action has been taken to date.
For the Widgeon sockeye, the thinking part continues, as it’s important we get the decision right.
Take a few minutes to review your notes and – when you’re ready – click below to take the quiz for this Lesson.