Fishing with Rod Discussion Forum
Fishing in British Columbia => General Discussion => Topic started by: Rodney on April 12, 2021, 10:11:13 AM
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Fraser Valley Invasive Species Society is hosting a webinar by biologist Wendy Margetts on invasive smallmouth bass in Cultus Lake. Find out how she is monitoring the population and how you can help. The webinar is at Noon and you can register at:
https://fviss.ca/event/smallmouthbass-cultus-presentation
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Nice short and informative presentation by Wendy. I'll post up the replay when FVISS releases it. Here is an interesting screenshot, the diet components of these smallmouth bass at Cultus Lake from last year's data collection.
(https://i.imgur.com/XOJEc3w.png)
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Sculpins and crayfish- who knew, lol! So if they aren't much of a threat to salmonids, why do they need to be eradicated?
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Dave! Sculpin lives matter! ;D
I think the concern is predation on pygmy sculpin, which are endangered. She hasn't been able to differentiate between coastrange and pygmy from the batch they extracted, so can't conclude how many eaten are in fact endangered pygmy.
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Right, the legendary Cultus Lake Pygmy sculpin. Forgot about them ...
I wonder when common sense will factor into some of these policies?
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I think there has been similar prey studies for SMB and LMB in the states that show they take few salmonids. If there is an issue in the Cultus data it's that they eat similar food items and may compete with trout.
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I didn't see the presentation but an interesting slide in regards to diet composition that's probably quite contrary to the average anglers preconception. Would anyone happen to have a similar analyses of diet composition for cultus pike minnow? I have always heard of how pike minnow (and now bass) prey on salmonoid fry. While this shows possibly a different picture, like Ralph commented it may not be so much that they are actually eating them but may still be out competing them for similar diets.
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How many samples over what period of time?
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Would anyone happen to have a similar analyses of diet composition for cultus pike minnow? I have always heard of how pike minnow (and now bass) prey on salmonoid fry.
I spent a lot of time looking at NPM stomachs back in the day. NPM have a unique digestive system in that food is broken down very quickly, making identification of contents difficult. Bass may have the same characteristics. Yes, fish bones were common but I never saw an identifiable salmonid. Sculpins and crayfish were the most common item but that may be because they take longer to digest. The only for sure time I know of NPM eating sockeye was a night trawl sampling trip where a NPM vomited up several juvenile sockeye.
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from my observations, Pike Minnow have a pronounced tendency to cannibalize smaller members of their species. They also travel in shoals. I have run into cases where larger PMs regurgitated smaller PMs regularly.
If they do tend to puke stomach contents when stressed it may partially explain why you didn't see much in their stomach's Dave.
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I wonder if it is possible to DNA test their scat, like is done with Orcas and seals, to determine what they have been eating? I also wonder about seasonality - when I have fished for smallmouth, I almost always use a crawfish-imitating plastic grub, but there are definitely periods of time that they seem indifferent to crawfish presentations. When I use a micro-tube, about the size of a salmon fry, I can't keep the juvenile smallmouth away (6-8 inches). So I guess I'm suggesting that it is worth sampling smallmouth at different life stages, as their prey will vary considerably, as well as taking seasonal samples to see how much their diet varies throughout the year.
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from my observations, Pike Minnow have a pronounced tendency to cannibalize smaller members of their species. They also travel in shoals. I have run into cases where larger PMs regurgitated smaller PMs regularly.
If they do tend to puke stomach contents when stressed it may partially explain why you didn't see much in their stomach's Dave.
That’s a good point Ralph. As I recall, the stomach of a NPM is like a straight chute from the throat to the anus, making regurgitation an easy operation. One point I found interesting was the chironomid feeding, making the comment from Coho Jake regarding size classes and prey very relevant.
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I've caught PMs on dry flies in Kootenay Lake. Crawford Bay once had a large shoreline population of PMs and they'd rise to the evening mayfly hatches in late spring. Both PMs and SMB are far more trout like than most give them credit. BTW I have also found crayfish - & quite large ones in the stomachs of cutthroat. In lakes cutthroat switch their feeding strategy as they get past a lb or so in weight focusing more on sizable critters. Same with brown trout unless the waters they are in very rich in insect life.
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Nice short and informative presentation by Wendy. I'll post up the replay when FVISS releases it.
Thanks Rod. I'd like to watch the recording. I'm not plugged into this organization and I wasn't aware of the scheduled meeting until your post just a couple hours prior to start.
So if they aren't much of a threat to salmonids, why do they need to be eradicated?
I don't have your fisheries/research background, Dave, but isn't even 4% salmonid when extrapolated over the entire year, and over the entire biomass of bass in the lake, cause for concern?
I know we can't put the genie back in the bottle, but in my thinking, eradication can be the only desired outcome; there is no acceptable margin of error (predation).
Most of the attention of SMB in Cultus has focussed on sockeye predation, but I find the aggregate 41% diet of crayfish and sculpin to be a little alarming (...yet not unsurprising). Over time, what subtle changes will occur in the lake's ecosystem when we replace crayfish and sculpin biomass with SMB biomass?
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clarki,I think if this 4% was upper Fraser chinook or Thompson steelhead I would agree, but if these salmonids in this Cultus study are indeed sockeye they are hatchery fish put in the lake because the water quality has degraded to the point wild sockeye production is nearly nonexistent.
The reality is Cultus Lake is no longer a suitable lake for spawning or rearing sockeye, and imo the lake should not be managed as such. I don’t think there is enough littoral zone habitat to have a really large SMB population but what is there is making a decent sports fishery , ie two friends caught 5 bass there yesterday, all about a pound.
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Thanks Dave. I can appreciate that perspective.
What has happened that Cultus is no longer a suitable lake for spawning or rearing sockeye?
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I don't think anyone here is advocating that the situation be left as it is. If there is any good news it's that sport fishing provides the immediate response to the arrival of SMBs in Cultus Lake and the lower Fraser watershed.
I'd also like to point out that there are a lot of lakes and waterways just in BC that have SMB populations and there is not a lot of evidence their introduction has had a negative impact on any salmonid population. They have been in the lower Okanagan watershed for at least 50 to 60 years and the recovery of sockeye populations there over the last 30 years has taken place in spite of populations of SMBs and LMBs being present in Osoyoos Lake, Vaseaux Lake, Skaha Lake and the connecting waterways. Sockeye can now pass over the dam at OK Falls into Skaha yet that lake has hosted at least one bass tournament.
I don't know what other remediation have been suggested or is available other than sport fishing with a mandated kill. Anyone else have any ideas?
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Thanks Dave. I can appreciate that perspective.
What has happened that Cultus is no longer a suitable lake for spawning or rearing sockeye?
Cultus sockeye are unique in that they are all beach spawners, historically at Lindell Beach and a few other shore line beaches. Over the years the up welling groundwater did a great job of incubating sockeye and chum eggs, but this upwelling has been drastically altered and basically doesn't happen now. On top of that Eurasian Water Milfoil has encroached on spawning beaches, water has warmed considerably, and dissolved oxygen levels have dropped. Over fishing in past years and a myxosporean parasite that affected the fishes kidneys also played a big part in this stock's decline.
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I don't think anyone here is advocating that the situation be left as it is.
Why not?
It's a ditch now that has the prime ecology for bass not salmon.
I don't think Cultus lake sockeye need another 100 years of study
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Cultus sockeye are unique in that they are all beach spawners, historically at Lindell Beach and a few other shore line beaches. Over the years the up welling groundwater did a great job of incubating sockeye and chum eggs, but this upwelling has been drastically altered and basically doesn't happen now. On top of that Eurasian Water Milfoil has encroached on spawning beaches, water has warmed considerably, and dissolved oxygen levels have dropped. Over fishing in past years and a myxosporean parasite that affected the fishes kidneys also played a big part in this stock's decline.
"hits thanks button"
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Why not?
It's a ditch now that has the prime ecology for bass not salmon.
I don't think Cultus lake sockeye need another 100 years of study
Politically there is going to be pressure to do something to remove them even if it's too late, won't work and can't help the Cultus Sockeye. I bet the SMBs got into the lake naturally. Silver Lake just south across the border has them. They have been legally stocked in Washington by the WDFW. Now they are in Cultus they will probably move into the Vedder and Fraser. I think the Harrison will be very favorable habitat for them. It's very similar to some of the rivers I fished for them in Ontario though on a much larger scale. If that happens I don't know how the cutthroat population will fare. Experience in lakes such as St Mary's on Saltspring is the cutts adapt well and both simply move into separate niches. No one talks about getting them out of that lake or Shawnigan or Skaha. They have fit right in.
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Ralph, is there a waterway that connects Silver lake with Cultus lake? I know they were connected eons ago but don't think they are now.
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Ralph, is there a waterway that connects Silver lake with Cultus lake? I know they were connected eons ago but don't think they are now.
Silver Lake is relatively high in the hills and drains south through Maple Creek into the North Fork Nooksack River. I don't see any way it could connect to the north. It is far more likely that the SMB's came up the Vedder and swam up into Cultus, if they weren't introduced. Maple Creek has some cascading waterfalls, so no salmon can make it up to the lake.
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https://elevationmap.net/cultus-lake-british-columbia
the elevation rise north of Silver Lake is 10 feet meters or less before it descends down to the Lindell Valley and Frost Creek. Maybe it's possible the lake could be high enough at times to spill some water off to the north?
I am only saying this because I find it difficult to believe a member of the bucket brigade could transport bass from the Okanagan or the Gulf Islands and keep them alive long enough to move them to Cultus Lake. I remember someone else suggested the same idea for LMBs getting into the Sumas and Vedder from Judson and Laxton Lakes. I was very skeptical but am much less so now.
BTW Silver is a more alkaline lake than most we have in the valley. It had a nice trout fishery at one time.
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Silver Lake is relatively high in the hills and drains south through Maple Creek into the North Fork Nooksack River. I don't see any way it could connect to the north. It is far more likely that the SMB's came up the Vedder and swam up into Cultus...
sure but from where? Cultus is the first known location of SMBs in the Fraser watershed.
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sure but from where? Cultus is the first known location of SMBs in the Fraser watershed.
Or multiple fish dropped by eagles? There are quite a few aggressive eagles at Silver Lake, and I would imagine a SMB could survive a 5-10 minute flight no problem. :D
Is that really the first known location in the whole Fraser watershed? Are there none it the lakes in the Thompson system?
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sure but from where? Cultus is the first known location of SMBs in the Fraser watershed.
This is my point. I believe these bass were transported by people who knew exactly what they were doing. The niche provided by the NPM removals created a pretty good environment for the bass to populate the lake ... now have several year classes that are apparently thriving. When some of these fish reach 4 or 5 pounds this lake will busy with anglers.
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Or multiple fish dropped by eagles?
waterfowl transportation of larva spiny ray fry has been suggested as one method of introduction to nearby watershed the idea being they may be able to survive on the wet feathers.
best info I can find on Fraser Watershed.
The first recorded occurrence of smallmouth bass in the South Thompson River watershed was in Phillips Lake in 1999 (Steve Maricle,BC MOE Regional Biologist, pers. comm.; Ken Tsumura, pers. comm., cited in Hatfield and Pollard 2006). However, no local or downstream captures have since been recorded for this waterbody, suggesting a failed introduction or erroneous species identification (Steve Maricle,BC MOE Regional Biologist, pers. comm.). Smallmouth bass have been recently confirmed in Gardom Lake, where a gravel outlet filter was constructed by the BC MOE in 2007 to prevent downstream movement of spiny-rayed fish species during seasonal outflows (Steve Maricle,BC MOE Regional Biologist, pers. comm.).
Following an angler-reported occurrence of smallmouth bass in July 2006, BC MOE staff confirmed this species to be present in four mainstem lakes and the mainstem channel of Beaver Creek, a tributary of the Quesnel River north of Williams Lake, BC (see Table 35 and Figure 9). Based on the lack of historic stocking of bass species by government agencies in the middle Fraser River watershed and the geographic isolation of these confirmed occurrences from other known smallmouth bass populations in BC, it seems certain that they were established through one or more local, unauthorized introductions (Tom Wilkinson, BC MOE Regional Biologist, pers. comm.).
Smallmouth bass presence was confirmed for 50 waterbodies on Vancouver and the Gulf Islands, including 36 lakes and 14 streams (see Table 18). Unconfirmed occurrences for smallmouth bass were recorded for three additional lakes. Based on provincial watershed coding, confirmed and unconfirmed occurrence records for this species are distributed across 20 separate drainages, linked only by marine or estuarine waters.
First observation dates for Salmon River and Kawkawa Lake smallmouth bass are relatively recent, in 2000 and 2003, respectively (Tracy Cone, DFO Area, pers. comm.; Justin Peterson, Angler, pers. comm., cited in Hatfield and Pollard 2006). Neither population originated through authorized stocking activities (Erin Stoddard, BC MOE Regional Biologist, pers. comm.). This, together with the lack of direct physical connectivity between these waterbodies, suggests that their smallmouth bass populations originated through independent unauthorized introductions. Only a single capture of smallmouth bass has been reported for Kawkawa Lake, this individual weighing approximately 1.4 kg (Erin Stoddard, BC MOE Regional Biologist, pers. comm.). The lack of subsequent captures in this system may indicate a failed introduction attempt (Erin Stoddard, BC MOE Regional Biologist, pers. comm.).
https://waves-vagues.dfo-mpo.gc.ca/Library/337851.pdf
A Review of Yellow Perch (Perca Flavascens), Smallmouth Bass (Micropterus Dolomieu), Largemouth Bass (Micropterus Salmoides), Pumpkinseed (Lepomis Gibbosus), Walleye (Sander Vitreus) and Northern Pike (Esox Lucius) Distributions in British Columbia. 2009
FWIW I heard the Kawkawa report which was of a large dead female is now regarded as a hoax. I have heard of LMBs in Salmon but not SMBs. Either way it's though the illegal introduction was thought to have failed.
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Another quote from the paper above re: the spread of LMBs in the Fraser Valley:
McPhail (2007) states that largemouth bass dispersal into Lower Mainland Region occurred via the trans-boundary Sumas River system while local advocates for promotion and conservation of bass angling opportunities have advised government biologists of their belief that largemouth bass are naturally recruiting into waterbodies in the lower Fraser River watershed from long-established upstream sources on the Fraser River floodplain
so the Sumas River could offer a pipeline for bass populations introduced in Washington State into the Fraser Valley and subsequent distribution (or illegal local transport & introduction) in the Fraser Valley.
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Another quote from the paper above re: the spread of LMBs in the Fraser Valley:
so the Sumas River could offer a pipeline for bass populations introduced in Washington State into the Fraser Valley and subsequent distribution (or illegal local transport & introduction) in the Fraser Valley.
BTW what is your source for there being SMB in silver lake? I have never seen them there (I haven't fished it much) and I don't know of any in the Nooksack watershed (there are plenty of LMB though).
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You think I got Silver Lake in Whatcom confused with the multitude of other Silver Lakes in Washington? Could be! Whatcom Lake definitely has SMBs as do many other watersheds, many of which cross the border. Pretty hard to find definitve info as to where they is and where they ain't.
The first documented introduction of smallmouth bass in Washington occurred in 1924, when a shipment of smallmouth arrived from the “east” and was released by a private individual into a small lake on Blakely Island in the San Juans (Lampman 1946). Other early plants were made into Lake Washington in 1925 and into the Yakima River in 1926 (Lampman 1946). Since then, smallmouth have become widely distributed across Washington, and significant populations are now found in a fairly large number of Washington streams and lakes, including the Columbia, Snake, Yakima, Okanogan, and Grande Ronde Rivers, and Lake Washington, Lake Sammamish, Lake Whatcom, Lake Stevens, Lake Osoyoos, Moses Lake, Potholes Reservoir, and several other smaller lakes on either side of the Cascade Mountains (Wydoski and Whitney 1979) (Figure 8-2). WDFW has expanded the range of smallmouth bass in Washington through a program of selective transplantation aimed at increasing fishing opportunity and success rates for this highly-prized sport fish. In recent years, smallmouth bass have been successfully transplanted into Banks Lake (1981), Mayfield Lake (1982), Lake Whatcom (1983), Palmer Lake (1983), and Lake Goodwin (1984) (Fletcher 1986).
https://www.nwcouncil.org/sites/default/files/Vol._III_Ch._8__Smallmouth_Bass.pdf
this site lists 64 waters as where to fish for SMBs.
https://wdfw.wa.gov/species-habitats/species/micropterus-dolomieu#locations
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You think I got Silver Lake in Whatcom confused with the multitude of other Silver Lakes in Washington? Could be! Whatcom Lake definitely has SMBs as do many other watersheds, many of which cross the border. Pretty hard to find definitve info as to where they is and where they ain't.
https://www.nwcouncil.org/sites/default/files/Vol._III_Ch._8__Smallmouth_Bass.pdf
this site lists 64 waters as where to fish for SMBs.
https://wdfw.wa.gov/species-habitats/species/micropterus-dolomieu#locations
Yeah, there are lots of Silver Lakes! Lake Whatcom and Lake Samish both have SMB but both drain to the ocean in small streams, not via the Nooksack. I still favor my theory that LMB's got into the Fraser system via a flood event and Judson/Boundary lake. I know it has no natural outlet most of the time, but I also know that area floods when the Fraser floods.
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I think there's also a good chance they (LMB) spilled over from Silvermere lake. During freshet, the Fraser actually backs up into Silvermere (or within inches). I first encountered LMB in Stave river around 2003.
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I'm not sure if Judson or Silvermere had LMB first though..
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Doesn't Hatzic also have a large population of bass in it? That directly connects to the Fraser as well.
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I'm not sure if Judson or Silvermere had LMB first though..
I caught my first LMB out of Judson in March of 1990 or thereabouts. It was well known as a bass fishing lake already at that point.
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I caught my first LMB out of Judson in March of 1990 or thereabouts. It was well known as a bass fishing lake already at that point.
I caught bass in Judson Lake about 1970, think there were black crappie in the lake as well back then.
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I've got some good memories of Silvermere from the late 60s and 70s. There was an old dock with a diving board on the Highway. Starting Labour Day my Dad and I would fish worms from a float from there and had good catches of small cutthroat plus some very large Black Crappie. The spot became popular as did the eastern shore by the highway. There was a grassy field and was mostly used by sunbathers. It was about then the private rights to lake was asserted. Then the highway was widened and the shoulders posted as No Parking. We also caught crappie in come of the local soughs and lakes in the 60s. Whonnock had them by then. Where did they come from?
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Here is the replay of that webinar:
https://www.youtube.com/watch?v=VGyi6c8kYSw
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Thanks!
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I liked the part about them needing more money for more studying. Absolutely refreshing hearing scientists come to the conclusion
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I liked the part about them needing more money for more studying. Absolutely refreshing hearing scientists come to the conclusion
Then can expect a donation from you!
Have watched it all but they clarified that the 4% diet of salmonids were sockeye smolts and the data was gathered when the smolts exit the lake. I'd guess that a significant take for this endangered run?
Dave do you think that's so?
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Then can expect a donation from you!
Have watched it all but they clarified that the 4% diet of salmonids were sockeye smolts and the data was gathered when the smolts exit the lake. I'd guess that a significant take for this endangered run?
Dave do you think that's so?
If I thought Cultus Lake sockeye could be saved, then yes 4% would be significant. Thing is I don't believe these fish can be saved.
Rather than destroying bass nests for IMO misguided reasons, this could be a great opportunity to study the impacts bass can have on other fish species.
On another note, I wonder what percent sockeye would be in the resident Bull Trout?
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Here is the replay of that webinar:
https://www.youtube.com/watch?v=VGyi6c8kYSw
Some interesting info presented. Hope they continue to get the resources to continue their study.
Now that the SMB are there, and there's no possibility of eradication, now we'll have to live with it. Will be interesting to see if they can be managed in some way to limit negative impact...
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Watched the recording.
What I found interesting was the amount of predation of SMB adults on juveniles and the research that extensive culling of adults had the opposite intended effect by increasing bass populations due to decreased predation on juvies.
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Here’s what I know about cultus lake bass, they love John Kents pumpkin head fly.
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Fraser Valley Invasive Species Society researcher Wendy Margetts in the news today:
https://globalnews.ca/video/7901034/b-c-biologist-fights-invasive-fish-in-cultus-lake (https://globalnews.ca/video/7901034/b-c-biologist-fights-invasive-fish-in-cultus-lake)