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smnorris / bcfishpass

Model and monitor aquatic habitat connectivity in BC. Tools to plan and prioritize the assessment and remediation of barriers.
https://smnorris.github.io/bcfishpass
Apache License 2.0
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discard modelled natural barriers downstream of known WCT spawning? #525

Open smnorris opened 4 months ago

smnorris commented 4 months ago

Salmon and steelhead models do this. I think it makes sense for WCT - but should be confirmed by @nickw-CWF or other CWF modellers more familiar with the species.

At the moment this is moot, there are no barriers downstream of known habitat in ELKR.

nickw-CWF commented 4 months ago

This is a good question, and might warrant some further discussion. But due to the life histories of the various WCT populations (fluvial, adfluvial, resident), these natural barriers will still fragment the system (e.g., there might be an isolated population of resident WCT upstream of a falls, but the waterfall is still preventing any upstream migration).

I'm trying to remember how he handled this originally, but I think we already ignore natural barriers for accessibility/connectivity but don't change the barrier status in the underlying data?

smnorris commented 4 months ago

This probably requires a bit of digging. The access model query is the same as the other species, with the exception that we do not discard natural barriers based on upstream observations. I think the tweaks to the connectivity status were in the reporting, but I do not see the Elk specific connectivity query in current files. It is probably in there somewhere.

NewGraphEnvironment commented 2 months ago

It has been justified in the Elk in the past to not remediate stream crossing barriers because of intermixing with rainbow. Lots of digging necessary to really feel one understands it I bet but if I remember half correctly - there was some research in the area was showing that the rainbow hybridation part of the genes was getting watered out in favour of wct characteristics over time - theorized that perhaps because of the rough and wild conditions that wct are able to withstand (cold and turbid conditions). Maybe not that helpful for deciding whether to discard the natural barriers in a model run but relevant to a big cloudy picture of how all the full and partial barriers play together in wctville.