The PCR Dilemma

[npauls]

Originally Posted by horsetrader

Do you need someone to tell you when your oil needs changing your garden needs weeding or your fence needs staining? Why do you have to wait for scientific data to show you when a water system needs help I just hope by the time that happens there is still time. Just turning it in to another put and take lake is not the proper way to manage a fishery.

Especially when fisheries have mentioned in the past that they want all the southern reservoirs with walleye in them to be self sustaining.

[freeones]

Originally Posted by horsetrader

Do you need someone to tell you when your oil needs changing your garden needs weeding or your fence needs staining? Why do you have to wait for scientific data to show you when a water system needs help I just hope by the time that happens there is still time. Just turning it in to another put and take lake is not the proper way to manage a fishery.

That's exactly the point isn't it. I DON'T need people like you telling me when to change my oil, weed the garden, or stain my fence.

I prefer to do things based on sound reason and science, not based on what some self proclaimed internet experts suggest.

Why not? Who decided that? There are lots of them in this province that provide a great deal of enjoyment for people. Why must there only be one "right" way to manage a fishery? Who's to say the current management system isn't working?

[chubbdarter]

From SRD
2.3 million Walleye fry were stocked in Pine Coulee Reservoir in the spring of 2000, with another 1.8 million stocked in the spring of 2002. Stocking of cyprinids and suckers collected from Willow Creek was also done in 2000 to try to establish a forage base for Walleye. Since then we have sampled the reservoir to monitor the Walleye population as it develops. In 2003, 2004, 2007, and 2009 gill netting was conducted to sample for larger Walleye in open, deeper areas of the reservoir. In 2005 and 2006 test angling was conducted to further sample larger Walleye for mercury analysis. In 2003, 2004, 2007, 2008, and 2009 beach seine netting in shallow areas of the reservoir was conducted to sample for juvenile Walleye (young of the year).



Gill net results

In 2003 over 60 Walleye were caught with an average fork length of about 10-11 inches. These were from the 2000 stocking event.

In 2004 close to 100 Walleye were caught with an average fork length of about 11-12 inches.

In 2007 about 50 Walleye were caught with an average fork length of about 13 inches.


In 2009 almost 130 Walleye were caught with an average fork length just over 13 inches. Stomach contents were analysed and ages determined. Only a single Walleye was less than 12 inches fork length. Its fork length was about 9.5 inches and it was aged 2 years old. This fish is believed to have resulted from natural spawning (not a stocked fish). All the other Walleye were between 12 and 15 inches long and either age 6 or age 9. They came from either the 2000 or 2003 stocking events. Stomach content analysis showed that of all the Walleye caught in 2009, only one contained partially digested fish, while all others either had empty stomachs or only invertebrates in their stomachs, mostly amphipods (Gammarus).



Test angling results

In 2005 35 Walleye caught in the spring had an average fork length of 12 inches.

In 2006 31 Walleye caught in the spring had an average fork length of 13 inches.



Beach seining results

In 2003 no young of the year Walleye were captured.

In 2004 no young of the year Walleye were captured.

In 2007 5 young of the year Walleye were captured at a single site.

Walleye spawning was also confirmed in 2007 though the use of egg traps set over spawning habitat, mid-April though mid-May.

In 2008 5 young of the year Walleye were captured at two sites.

In 2009 7 young of the year Walleye were captured at four sites.

All young of the year Walleye were around 1.5 inches long.



Ten years after completion of the Pine Coulee Project, the overall conclusion from these results is that a dense population of Walleye from the 2000 and 2003 stocking events has developed, but the growth rate of these fish has gradually decreased to the point that they have almost stopped growing now. Although spawning is occurring, there appears to be very limited survival of naturally spawned young (only one fish caught in gill nets in 2009 was a two year old). Stomach content analyses demonstrate Walleye are not feeding on fish, but primarily on amphipods (invertebrates). This is likely limiting their growth. All fish but the one age 2 fish sampled in 2009 did appear to have mature gonads, suggesting they could spawn, but the limited prey base may mean not all Walleye have sufficient energy to actually spawn. Another possibility is that despite successful spawning, very few young of the year survive the first summer due to poor conditions for survival (cold weather, wind and wave action, poor rearing habitat) or larval predation by other forage species present in the reservoir. Beach seine netting in shallow areas of the reservoir has shown White Suckers and Longnose Suckers are abundant, but the Walleye are not feeding on them. Other species of forage fish such as Lake Chub, Spottail Shiners, Emerald Shiners, and Fathead Minnow are also present, but in lower numbers.



Walleye fisheries across Alberta are classified into one of four management categories. In southern Alberta, all waterbodies were classified into one of two categories: newly stocked or vulnerable. Reservoirs and lakes in the first category have a zero catch limit (catch and release) while those in the vulnerable category allow for limited harvest. According to Alberta's Walleye Management and Recovery Plan, changes to the management status category (e.g., from newly stocked to vulnerable) are based on five biological characteristics: age-class distribution, age-class stability, growth, age-at-maturity, and catch rate. Although catch rate meets the criteria for changing the status category of Pine Coulee Reservoir,growth rate, age-at-maturity, age-class distribution, and age-class stability do not. Walleye in Pine Coulee Reservoir have reached maturity rapidly, the age-class distribution is extremely narrow (essentially only fish from the 2000 and 2003 stocking events are represented), and age-class stability is very low (if these two age classes were lost to overharvest there would be no younger age classes to fill their place). In order to change Pine Coulee Reservoir from the newly stocked to vulnerable category we need to have biological evidence that juvenile Walleye are surviving, reaching sexual maturity, and spawning successfully.



We will continue to monitor the reservoir and evaluate the feasibility of various options for establishing a sustainable fishery. A risk assessment considering the impacts to the reservoir itself, as well as to Willow Creek, would be required before considering introducing another prey species for Walleye. In terms of allowing limited harvest, a decision will have to be reach on whether a self sustaining Walleye fish can be established before this is considered. One factor to note is that a consumption advisory is in place for Walleye from this reservoir. Although concentrations of total mercury in analysed walley from Pine Coulee Reservoir (0.52 to 0.79 micrograms/gram) were within reported ranges for Walleye from rivers and lakes elsewhere in Canada and the United States, they were also above the threshold (0.5 micrograms/gram) where Health Canada recommends limits for consumption for different consumer groups (women, children, adults).



If you have any further questions about fisheries management on Pine Coulee Reservoir, please feel free to contact me again.

[horsetrader]

Originally Posted by chubbdarter

From SRD
2.3 million Walleye fry were stocked in Pine Coulee Reservoir in the spring of 2000, with another 1.8 million stocked in the spring of 2002. Stocking of cyprinids and suckers collected from Willow Creek was also done in 2000 to try to establish a forage base for Walleye. Since then we have sampled the reservoir to monitor the Walleye population as it develops. In 2003, 2004, 2007, and 2009 gill netting was conducted to sample for larger Walleye in open, deeper areas of the reservoir. In 2005 and 2006 test angling was conducted to further sample larger Walleye for mercury analysis. In 2003, 2004, 2007, 2008, and 2009 beach seine netting in shallow areas of the reservoir was conducted to sample for juvenile Walleye (young of the year).



Gill net results

In 2003 over 60 Walleye were caught with an average fork length of about 10-11 inches. These were from the 2000 stocking event.

In 2004 close to 100 Walleye were caught with an average fork length of about 11-12 inches.

In 2007 about 50 Walleye were caught with an average fork length of about 13 inches.


In 2009 almost 130 Walleye were caught with an average fork length just over 13 inches. Stomach contents were analysed and ages determined. Only a single Walleye was less than 12 inches fork length. Its fork length was about 9.5 inches and it was aged 2 years old. This fish is believed to have resulted from natural spawning (not a stocked fish). All the other Walleye were between 12 and 15 inches long and either age 6 or age 9. They came from either the 2000 or 2003 stocking events. Stomach content analysis showed that of all the Walleye caught in 2009, only one contained partially digested fish, while all others either had empty stomachs or only invertebrates in their stomachs, mostly amphipods (Gammarus).



Test angling results

In 2005 35 Walleye caught in the spring had an average fork length of 12 inches.

In 2006 31 Walleye caught in the spring had an average fork length of 13 inches.



Beach seining results

In 2003 no young of the year Walleye were captured.

In 2004 no young of the year Walleye were captured.

In 2007 5 young of the year Walleye were captured at a single site.

Walleye spawning was also confirmed in 2007 though the use of egg traps set over spawning habitat, mid-April though mid-May.

In 2008 5 young of the year Walleye were captured at two sites.

In 2009 7 young of the year Walleye were captured at four sites.

All young of the year Walleye were around 1.5 inches long.



Ten years after completion of the Pine Coulee Project, the overall conclusion from these results is that a dense population of Walleye from the 2000 and 2003 stocking events has developed, but the growth rate of these fish has gradually decreased to the point that they have almost stopped growing now. Although spawning is occurring, there appears to be very limited survival of naturally spawned young (only one fish caught in gill nets in 2009 was a two year old). Stomach content analyses demonstrate Walleye are not feeding on fish, but primarily on amphipods (invertebrates). This is likely limiting their growth. All fish but the one age 2 fish sampled in 2009 did appear to have mature gonads, suggesting they could spawn, but the limited prey base may mean not all Walleye have sufficient energy to actually spawn. Another possibility is that despite successful spawning, very few young of the year survive the first summer due to poor conditions for survival (cold weather, wind and wave action, poor rearing habitat) or larval predation by other forage species present in the reservoir. Beach seine netting in shallow areas of the reservoir has shown White Suckers and Longnose Suckers are abundant, but the Walleye are not feeding on them. Other species of forage fish such as Lake Chub, Spottail Shiners, Emerald Shiners, and Fathead Minnow are also present, but in lower numbers.



Walleye fisheries across Alberta are classified into one of four management categories. In southern Alberta, all waterbodies were classified into one of two categories: newly stocked or vulnerable. Reservoirs and lakes in the first category have a zero catch limit (catch and release) while those in the vulnerable category allow for limited harvest. According to Alberta's Walleye Management and Recovery Plan, changes to the management status category (e.g., from newly stocked to vulnerable) are based on five biological characteristics: age-class distribution, age-class stability, growth, age-at-maturity, and catch rate. Although catch rate meets the criteria for changing the status category of Pine Coulee Reservoir,growth rate, age-at-maturity, age-class distribution, and age-class stability do not. Walleye in Pine Coulee Reservoir have reached maturity rapidly, the age-class distribution is extremely narrow (essentially only fish from the 2000 and 2003 stocking events are represented), and age-class stability is very low (if these two age classes were lost to overharvest there would be no younger age classes to fill their place). In order to change Pine Coulee Reservoir from the newly stocked to vulnerable category we need to have biological evidence that juvenile Walleye are surviving, reaching sexual maturity, and spawning successfully.



We will continue to monitor the reservoir and evaluate the feasibility of various options for establishing a sustainable fishery. A risk assessment considering the impacts to the reservoir itself, as well as to Willow Creek, would be required before considering introducing another prey species for Walleye. In terms of allowing limited harvest, a decision will have to be reach on whether a self sustaining Walleye fish can be established before this is considered. One factor to note is that a consumption advisory is in place for Walleye from this reservoir. Although concentrations of total mercury in analysed walley from Pine Coulee Reservoir (0.52 to 0.79 micrograms/gram) were within reported ranges for Walleye from rivers and lakes elsewhere in Canada and the United States, they were also above the threshold (0.5 micrograms/gram) where Health Canada recommends limits for consumption for different consumer groups (women, children, adults).





If you have any further questions about fisheries management on Pine Coulee Reservoir, please feel free to contact me again.

Definitely some interesting info. huge numbers of stocked fish with very little growth and so sustainable spawning. This is a fishery that is going to need continuing help or it can easily lost. No wheres near the health fishery some would lead you to believe. Thanks for the information Chubb.

Im thinking that amount of reproduction could be more sustainable than you may think. Walleye fry seining is not generally used quantitatively, rather, its used to confirm reproduction. To see what i mean, find out how many fry were seined the same years it was stocked with millions, it may surprise you how few show up in sampling.
They did find 3 consequetive years of spawning, thats better than a lot of our walleye populations in reservoirs ever get. When i fished PCR last winter, we used very small jigs and caught a fair number of perch size (6-8'') walleye, they are in there. Survival of the new gernerations could be limited though, consider all the burbot, pike, suckers, and other walleye they have to contend with. Growth rates suck, part of that is the reservoir was definetly stocked earlier than would have been optimal (not many years for forage base to develop). As the lake gets older it should improve, more weeds and forage can take a long time. More weeds alone would greatly benefit walleye fry by providing cover and a far greater biomass of prey (scuds etc).
The smallest of the walleye we caught last winter (some as small as 4-5'') were plump little guys, the bigger ones were skinny, i think this supports the idea theres a feeding "problem". Big sucker population, i wonder if a 0 limit or slot on pike would be worth trying. Big pike may help to thin out the suckers a bit, less competition on a biomass level.

[aulrich]

Good to hear at least some spawning happening, I would think the real critical years will be those last few before the initial stock die of old age. And maybe at that point more age classes start showing up and the size improves.

I did a little googling and it seems 10-20 years is the widest span so i'd imagine we have 5 ish years or so before we see the numbers really start to drop. My "hope" is during that time recrutment will also rise and the lake settles into a grove.

The fishing will not get any better than it is now, at least numbers wise, so enjoy it while it lasts.

[WayneChristie]

JRS, there are a lot more pike and much bigger pike in PCR than people think, Ive had the pleasure of making the aquaintance of one, for a short time anyways, 4 pound test isnt really the best for very large fish. I think with all the food for them (walleye) that in the next few years we are going to see some crazy heavy fish coming out of there. Like record size, if not heavier.
Thank you for the very informative post Mr Darter!

[calgarygringo]

I have fished many days there winter and summer. There is definitely a starvation problem with the wallys but no issues with the pike. There are many monsters in there. I have caught many in the 10-15 lb range and seen a few at the dock like some of the southern lakes. they are in there and have always been well fed looking fish. I did talk to the CO there a year or so ago and suggested some new fish such as perch, whites or just a minnow type population. He did say perch is out due to issues we are having in a lot of places and said whites the same. Said whites don't have a good survival rate on a stocking and a natural production over years works better. He was not sure about adding some kind of minnow type food as an alternative. This will turn into a pike trophy lake one of these days. There will be huge ones coming out regularly at the rate they are growing. the CO also said that the pike they had checked in there are growing at almost twice the rate of most reservoirs. I don't know where the number came from but they were doing netting there at the time as well.

[iliketrout]

Chubb thanks for the info. Good to have hard data to support what many anglers are reporting.

Does SRD have any sort of plan if/when the population crashes?

[Daceminnow]

thanks very much chubb for sharing with us your communication with the SRD.

it is definitely good to see it has been determined that successful spawning has occurred. with poor rearing habitat mentioned as one of the factors contributing to the juvenile walleye surviving, reaching sexual maturity, and spawning successfully, i wonder if there's any plans to improve the habitat. i know stream improvements in the province have been done to improve spawning and rearing grounds. is it possible for these same types of habitat improvements to be made in lakes and reservoirs as well? or is it just that PCR is a relatively new reservoir and it will take some time to develop new and better habitat for the young to utilize and survive? we stay out of it, and let the ecosystem look after itself and our fish. i also found it interesting to note they mentioned the consumption advisory. i don't quite understand how that aspect fits in with all the excellent information and data that was shared.

Dace

thanks for everyones comments on pcr. havent fished there before so dont know much about it but thought i might throw my 2 bits out there too.

a lake system can only support a fixed level of biomass and thats it. usually and naturally that biomass is balanced across something called a food chain.

i strongly strongly suggest that it might be a bad idea to ever adjust a water bodies biomass by stocking a single species(unless your trying o repair previous damage). otherwise you only introduce a shock to the system which has to kick it out of balance. One really big link in the chain.

the fish are in a slow stavation cycle. you may disagree but the fact they kill everything you drop in might just be a hint about the feeding pressure.

the population will eventually crash and die off from age or disease. good for the pike right now but that is just a little longer cycle which will crash eventually too.

now could it be fixed. sure just start adjusting the biomass
possibly some commercial netting of walleye. then addition of some walleye, pke and feeder minnows in a set balance.


but i wonder if anyone wants a balanced system. or maybe with the fishing pressures we have today, can we even have a balanced system.

thats my thoughts.. thanks for reading.

[horsetrader]

Originally Posted by jrs

Im thinking that amount of reproduction could be more sustainable than you may think. Walleye fry seining is not generally used quantitatively, rather, its used to confirm reproduction. To see what i mean, find out how many fry were seined the same years it was stocked with millions, it may surprise you how few show up in sampling.
They did find 3 consequetive years of spawning, thats better than a lot of our walleye populations in reservoirs ever get. When i fished PCR last winter, we used very small jigs and caught a fair number of perch size (6-8'') walleye, they are in there. Survival of the new gernerations could be limited though, consider all the burbot, pike, suckers, and other walleye they have to contend with. Growth rates suck, part of that is the reservoir was definetly stocked earlier than would have been optimal (not many years for forage base to develop). As the lake gets older it should improve, more weeds and forage can take a long time. More weeds alone would greatly benefit walleye fry by providing cover and a far greater biomass of prey (scuds etc).
The smallest of the walleye we caught last winter (some as small as 4-5'') were plump little guys, the bigger ones were skinny, i think this supports the idea theres a feeding "problem". Big sucker population, i wonder if a 0 limit or slot on pike would be worth trying. Big pike may help to thin out the suckers a bit, less competition on a biomass level.

There seems to be quite a size problem there seems to be very little size increase between 2007 and 2009 with 130 walleye caught in 2009 and only 1 being under the 12" mark and that being the only naturally spawned fish. It will be interesting to see over the next few years just what happens. I can see the younger fish can survive and grow on just invertebrates but as they mature they need more food source or they will become a very stunted fishery. I don't know if a harvest of walleye would really change things that much it will give possibly more invertebrates per fish but will that be enough to increase fish size. Or is introducing another food source the way to go.

[AK47]

Why not stock perch in there? Perch would be perfect as it will be a great food for both walleye and burbot and pike.

[npauls]

Originally Posted by AK47

Why not stock perch in there? Perch would be perfect as it will be a great food for both walleye and burbot and pike.

The problem with the perch would be that they could escape and spread through other water systems connected to pcr and take over like they have in many other places.

I think whitefish, shiners, or chubbs would be a good addition if they were to stock a bait fish.

[AK47]

Originally Posted by npauls

The problem with the perch would be that they could escape and spread through other water systems connected to pcr and take over like they have in many other places.

I think whitefish, shiners, or chubbs would be a good addition if they were to stock a bait fish.

what is connected to PCR? Is there such a huge risk?

[npauls]

If I remember right I think it drains back out into a small creek system which feeds some other smaller waters.

I will have to look it up to make sure and get back to you on what it is connected to.

I know that Alberta fisheries is really iffy about perch right now due to so many small waters filled with stunted perch.

[Dan Foss]

Very Very interesting information and thank you to chubbs for providing it and all your hard work on the several projects you have going on right now.

A few things caught my attention.....

I know a bunch of you are still discussing if stocking prey species is a viable option to raise size.... However, from books that I have read and if some of our actual bios on the board would like to chime in to clairify that would be awesome, it seems to me that what I have read follows a similar line to what pelada trochu was referring to when he brought up that a lake can only support a fixed level of biomass and the entire ecosystem including forage can be messed when you add large quantities of fish like has occurred at PCR. However, I dont believe removing biomas and trying to force a balance by introducing pike and forage would be an answer. Now that it has been confirmed that there has been spawning on whatever limited basis, the first thing that I believe would need to be studied is the spawning success rates and a estimation of percentage of fry that survive. Then It would need to be determined what the biggest threats are to the young fry. This is where we could possibly best help out the fishery. In this stage we could determine if it is that there the environment proposes the greatest challenges to young fry, then we can look into improving breeding grounds, improving sections of the lake to provide cover for young fry which in tern may also provide additional cover for forage fish and increase those populations.

It could be that midsize pike are feeding on the young walleye as there are no fish populations the right size for the size pike(obviously the large pike will feed on walleye, burbs, suckers, ect. but what of the pike that are not quite big enough for that size meal...... they certainly are not going to jump size classes by feeding on shrimp and such like the walleye do)

My point is that with the confirmation of successful spawning, the next step should be to learn why we are not seeing higher rates of these age classes. I definitely donot dispute that this lake shouldn't be considered for a reduction in walleye biomass as I believe it is clear that food competition is definitely a primary issue which may also be effecting development of young fry, but before anything is done I believe that there should be questions investigated regarding spawning success, fry survival, reasons why there are such low survival rates, and why there is currently such small populations of forage fish.

I also agree that it takes a long time for a lake to establish beds for large populations of forage. But this may also be an area that couple be assisted with.

once again very interesting information and great contribution guys

[horsetrader]

Originally Posted by Dan Foss

Very Very interesting information and thank you to chubbs for providing it and all your hard work on the several projects you have going on right now.

A few things caught my attention.....

I know a bunch of you are still discussing if stocking prey species is a viable option to raise size.... However, from books that I have read and if some of our actual bios on the board would like to chime in to clairify that would be awesome, it seems to me that what I have read follows a similar line to what pelada trochu was referring to when he brought up that a lake can only support a fixed level of biomass and the entire ecosystem including forage can be messed when you add large quantities of fish like has occurred at PCR. However, I dont believe removing biomas and trying to force a balance by introducing pike and forage would be an answer. Now that it has been confirmed that there has been spawning on whatever limited basis, the first thing that I believe would need to be studied is the spawning success rates and a estimation of percentage of fry that survive. Then It would need to be determined what the biggest threats are to the young fry. This is where we could possibly best help out the fishery. In this stage we could determine if it is that there the environment proposes the greatest challenges to young fry, then we can look into improving breeding grounds, improving sections of the lake to provide cover for young fry which in tern may also provide additional cover for forage fish and increase those populations.

It could be that midsize pike are feeding on the young walleye as there are no fish populations the right size for the size pike(obviously the large pike will feed on walleye, burbs, suckers, ect. but what of the pike that are not quite big enough for that size meal...... they certainly are not going to jump size classes by feeding on shrimp and such like the walleye do)

My point is that with the confirmation of successful spawning, the next step should be to learn why we are not seeing higher rates of these age classes. I definitely donot dispute that this lake shouldn't be considered for a reduction in walleye biomass as I believe it is clear that food competition is definitely a primary issue which may also be effecting development of young fry, but before anything is done I believe that there should be questions investigated regarding spawning success, fry survival, reasons why there are such low survival rates, and why there is currently such small populations of forage fish.

I also agree that it takes a long time for a lake to establish beds for large populations of forage. But this may also be an area that couple be assisted with.

once again very interesting information and great contribution guys

You bring up some good points but I still think the main problem to be concerned with is an acceptable food source for the mature walleye. What is the sense in developing the spawning just to have another water system full of stunted fish.

[Dan Foss]

Originally Posted by horsetrader

You bring up some good points but I still think the main problem to be concerned with is an acceptable food source for the mature walleye. What is the sense in developing the spawning just to have another water system full of stunted fish.

Yes I meant to mention that as well. It appears that forage is an issue and i meant to make the connection that whatever issues there are with the young fry walleye may be the same reason why the forage populations are so low as well. For example if it is a protection issue where they are not seeing enough areas in the lake where they can hide from the mid size pike, is it excessive competition for food to the point where forage populations would be larger if the general biomass was smaller....(more forage fish per walleye and higher forage populations if there were less mouths to feed)

it appears that the issue with PCR is not one solitary issue bur perhaps a combination of various issues: a) spawning success rates b) coverage for forage as well as fry b) too large of a bio mass of a single walleye class.

A couple other possibilities for some of these issues that have popped in my head while thinking about the issue off the forum: is it possible that one reason why low success rates or spawn is due to the burbot population feeding on fry and walleye eggs? Is it possible that the forage populations would be at a healthy, self sustaining level if there were fewwer walleye of the same year class? It is clear that there is alot of small food sources as it has been proven that this is primarily what the walleye eat; given that, forage fish should have plenty of food to support a large population. Is it possible that with such high populations of walleye that they are just whipping out the forage fish preventing them from establishing the population capabilities that they should be able to achieve given the food source?


I just had a little realization....... I almost like fish and fishing way to much. These discussions are 1000x more interesting than anything on TV. I feel sorry for some of my friends that have to listen to me talk about this stuff for hours and probably just sit there thinking im crazy

[WayneChristie]

Originally Posted by Dan Foss

I just had a little realization....... I almost like fish and fishing way to much. These discussions are 1000x more interesting than anything on TV. I feel sorry for some of my friends that have to listen to me talk about this stuff for hours and probably just sit there thinking im crazy

Too much? nah, not possible
more interesting than tv? so is picking belly button lint for the most part!
and if you are crazy for that, join the club, Im a proud member myself

[slough shark]

fairly simple solution in my mind anyways, reduce walleye biomass by allowing a limit of a couple walleye to be taken, this followed by a mass introduction of feeder fish, I'm thinking some minnow type (shiners perhaps) as well as whitefish. I is possible for a few years of chaos but after a few years it would likely balance out and there may be a balanced fishery at the end of it all. The pike that are already in there would bring the biomass down as the feeder fish would allow the pike to develop at a normal rate. 1 reg change there should be right now, no keeping pike for a few years there and keeping say 2 walleye.

[freeones]

Originally Posted by chubbdarter

From SRD
2.3 million Walleye fry were stocked in Pine Coulee Reservoir in the spring of 2000, with another 1.8 million stocked in the spring of 2002. Stocking of cyprinids and suckers collected from Willow Creek was also done in 2000 to try to establish a forage base for Walleye. Since then we have sampled the reservoir to monitor the Walleye population as it develops. In 2003, 2004, 2007, and 2009 gill netting was conducted to sample for larger Walleye in open, deeper areas of the reservoir. In 2005 and 2006 test angling was conducted to further sample larger Walleye for mercury analysis. In 2003, 2004, 2007, 2008, and 2009 beach seine netting in shallow areas of the reservoir was conducted to sample for juvenile Walleye (young of the year).



Gill net results

In 2003 over 60 Walleye were caught with an average fork length of about 10-11 inches. These were from the 2000 stocking event.

In 2004 close to 100 Walleye were caught with an average fork length of about 11-12 inches.

In 2007 about 50 Walleye were caught with an average fork length of about 13 inches.


In 2009 almost 130 Walleye were caught with an average fork length just over 13 inches. Stomach contents were analysed and ages determined. Only a single Walleye was less than 12 inches fork length. Its fork length was about 9.5 inches and it was aged 2 years old. This fish is believed to have resulted from natural spawning (not a stocked fish). All the other Walleye were between 12 and 15 inches long and either age 6 or age 9. They came from either the 2000 or 2003 stocking events. Stomach content analysis showed that of all the Walleye caught in 2009, only one contained partially digested fish, while all others either had empty stomachs or only invertebrates in their stomachs, mostly amphipods (Gammarus).



Test angling results

In 2005 35 Walleye caught in the spring had an average fork length of 12 inches.

In 2006 31 Walleye caught in the spring had an average fork length of 13 inches.



Beach seining results

In 2003 no young of the year Walleye were captured.

In 2004 no young of the year Walleye were captured.

In 2007 5 young of the year Walleye were captured at a single site.

Walleye spawning was also confirmed in 2007 though the use of egg traps set over spawning habitat, mid-April though mid-May.

In 2008 5 young of the year Walleye were captured at two sites.

In 2009 7 young of the year Walleye were captured at four sites.

All young of the year Walleye were around 1.5 inches long.



Ten years after completion of the Pine Coulee Project, the overall conclusion from these results is that a dense population of Walleye from the 2000 and 2003 stocking events has developed, but the growth rate of these fish has gradually decreased to the point that they have almost stopped growing now. Although spawning is occurring, there appears to be very limited survival of naturally spawned young (only one fish caught in gill nets in 2009 was a two year old). Stomach content analyses demonstrate Walleye are not feeding on fish, but primarily on amphipods (invertebrates). This is likely limiting their growth. All fish but the one age 2 fish sampled in 2009 did appear to have mature gonads, suggesting they could spawn, but the limited prey base may mean not all Walleye have sufficient energy to actually spawn. Another possibility is that despite successful spawning, very few young of the year survive the first summer due to poor conditions for survival (cold weather, wind and wave action, poor rearing habitat) or larval predation by other forage species present in the reservoir. Beach seine netting in shallow areas of the reservoir has shown White Suckers and Longnose Suckers are abundant, but the Walleye are not feeding on them. Other species of forage fish such as Lake Chub, Spottail Shiners, Emerald Shiners, and Fathead Minnow are also present, but in lower numbers.



Walleye fisheries across Alberta are classified into one of four management categories. In southern Alberta, all waterbodies were classified into one of two categories: newly stocked or vulnerable. Reservoirs and lakes in the first category have a zero catch limit (catch and release) while those in the vulnerable category allow for limited harvest. According to Alberta's Walleye Management and Recovery Plan, changes to the management status category (e.g., from newly stocked to vulnerable) are based on five biological characteristics: age-class distribution, age-class stability, growth, age-at-maturity, and catch rate. Although catch rate meets the criteria for changing the status category of Pine Coulee Reservoir,growth rate, age-at-maturity, age-class distribution, and age-class stability do not. Walleye in Pine Coulee Reservoir have reached maturity rapidly, the age-class distribution is extremely narrow (essentially only fish from the 2000 and 2003 stocking events are represented), and age-class stability is very low (if these two age classes were lost to overharvest there would be no younger age classes to fill their place). In order to change Pine Coulee Reservoir from the newly stocked to vulnerable category we need to have biological evidence that juvenile Walleye are surviving, reaching sexual maturity, and spawning successfully.



We will continue to monitor the reservoir and evaluate the feasibility of various options for establishing a sustainable fishery. A risk assessment considering the impacts to the reservoir itself, as well as to Willow Creek, would be required before considering introducing another prey species for Walleye. In terms of allowing limited harvest, a decision will have to be reach on whether a self sustaining Walleye fish can be established before this is considered. One factor to note is that a consumption advisory is in place for Walleye from this reservoir. Although concentrations of total mercury in analysed walley from Pine Coulee Reservoir (0.52 to 0.79 micrograms/gram) were within reported ranges for Walleye from rivers and lakes elsewhere in Canada and the United States, they were also above the threshold (0.5 micrograms/gram) where Health Canada recommends limits for consumption for different consumer groups (women, children, adults).

If you have any further questions about fisheries management on Pine Coulee Reservoir, please feel free to contact me again.

Great info Chubdarter. That's the kind of thing you can make informed decisions with.

Here's my take on it -

Everything is just fine, and while it's going to change over time, it's going to be just fine in the future too.

The best news to come out of that is that there is successful spawning and replacement in PCR. That's good evidence that the walleye population in PCR can be self sustaining at some level. Probably not at today's level, but that level is artificial, and could likely be maintained through periodic stocking.

IMHO, this boils down to exactly what a few others have talked about - overall biomass and the quality of the lake itself. No matter what "solution" is proposed, there's very little that can be done about those factors, they're fixed and finite.

The relatively low recruitment numbers speak more to the forage base and quality of the reservoir habitat than anything else. Like any other ecosystem, it's working toward balance. Every doe in the herd doesn't have twins after a particulary harsh fall and winter, and if the spring/summer are brutal, it's the fawns that are first to die. I don't see the walleye population being any different. When the stocked age classes begin dieing off, then recruitment will step up to help fill void left in the available biomass.

Stocking forage, having a limited harvest, changing the structure of the lake, etc... will all have major effects on the ecosystem. In a relatively fixed system like PCR, those are all short term fixes aimed at a particular goal - to increase the size of the walleye population at the expense of the overall numbers of walleye. I don't agree with that line of thinking, not every lake needs to be managed as a "trophy" fishery, and furthermore, I don't think every lake can be managed that way. PCR isn't much more than big slough, it's never going to be a true trophy walleye fishery.

I wouldn't screw around with it if it was me, nature will take care of it itself, and those wanting fewer numbers and bigger fish will get their way eventually, just by doing nothing.

The lake has forage species (shiners, fathead minnows, chubs, all stocked or can enter through the inlet canal, screens are not sufficient to stop young of year cyprinids, or burbot, or suckers for that matter). Very low numbers of minnows in the lake from what i understand, plenty of suckers though. I just don't know if i can see walleye harvest being allowed, aside from the tag system, the lake is too close to Calgary.

[horsetrader]

Originally Posted by freeones

Great info Chubdarter. That's the kind of thing you can make informed decisions with.

Here's my take on it -

Everything is just fine, and while it's going to change over time, it's going to be just fine in the future too.

The best news to come out of that is that there is successful spawning and replacement in PCR. That's good evidence that the walleye population in PCR can be self sustaining at some level. Probably not at today's level, but that level is artificial, and could likely be maintained through periodic stocking.

IMHO, this boils down to exactly what a few others have talked about - overall biomass and the quality of the lake itself. No matter what "solution" is proposed, there's very little that can be done about those factors, they're fixed and finite.

The relatively low recruitment numbers speak more to the forage base and quality of the reservoir habitat than anything else. Like any other ecosystem, it's working toward balance. Every doe in the herd doesn't have twins after a particulary harsh fall and winter, and if the spring/summer are brutal, it's the fawns that are first to die. I don't see the walleye population being any different. When the stocked age classes begin dieing off, then recruitment will step up to help fill void left in the available biomass.

Stocking forage, having a limited harvest, changing the structure of the lake, etc... will all have major effects on the ecosystem. In a relatively fixed system like PCR, those are all short term fixes aimed at a particular goal - to increase the size of the walleye population at the expense of the overall numbers of walleye. I don't agree with that line of thinking, not every lake needs to be managed as a "trophy" fishery, and furthermore, I don't think every lake can be managed that way. PCR isn't much more than big slough, it's never going to be a true trophy walleye fishery.

I wouldn't screw around with it if it was me, nature will take care of it itself, and those wanting fewer numbers and bigger fish will get their way eventually, just by doing nothing.

Sorry but if you read the information you will see the numbers are going up but the size is not so what you will end up with is another stunted walleye fishery until it dies. Without a proper food source the fish will not increase in size and reproduction will be minimal.

[oilngas]

Chub Darter;
I agree that things are just fine, the grandkids really enjoy catching the smallish walleye. They are of age where catching is way more important than fishing, they are after grandpa to take then out on the ice ASAP. I know that after a few hour on the lake we will be back heading to town with tired and happy kids.
it's great to have this resource so close to Calgary

[Dan Foss]

Originally Posted by oilngas

Chub Darter;
I agree that things are just fine, the grandkids really enjoy catching the smallish walleye. They are of age where catching is way more important than fishing, they are after grandpa to take then out on the ice ASAP. I know that after a few hour on the lake we will be back heading to town with tired and happy kids.
it's great to have this resource so close to Calgary

Sure, It is a great location. Nice and close to calgary, the dock is set up in a prime spot for fishermen just off that weed bed and dropoff(awesome walleye structure in any lake). But let me pose the question to you in this format:

My interpretation of the information provided is that there is a confirmation that there is a lack of forage base, extremely heavy competition for food, and either low spawning rates or low survival rates for fry. Given these facts, the fishery will eventually die off as there seems to be only 2 year classes of walleye in the lake. what would you propose then? a massive restocking to create 2 definitive year classes again so we can maintain our catch rates of 100+ stunted walleye in a trip? I can greatly appreciate the family value aspect that PCR has but here is the million dollar question: Would you be willing to sacrifice your 100+ walleye/day numbers for a lower 20-30 walleye/day if the walleye were varied in sizes (some big some small) if it meant the lake was NATURALLY restocking itself with young of the year? As a family you could still go there in a couple of hours everyone will have caught multiple fish. The fishing off the dock will always be really good given the structure that the dock sits on.

[Bigdad013]

Originally Posted by Dan Foss

Sure, It is a great location. Nice and close to calgary, the dock is set up in a prime spot for fishermen just off that weed bed and dropoff(awesome walleye structure in any lake). But let me pose the question to you in this format:

My interpretation of the information provided is that there is a confirmation that there is a lack of forage base, extremely heavy competition for food, and either low spawning rates or low survival rates for fry. Given these facts, the fishery will eventually die off as there seems to be only 2 year classes of walleye in the lake. what would you propose then? a massive restocking to create 2 definitive year classes again so we can maintain our catch rates of 100+ stunted walleye in a trip? I can greatly appreciate the family value aspect that PCR has but here is the million dollar question: Would you be willing to sacrifice your 100+ walleye/day numbers for a lower 20-30 walleye/day if the walleye were varied in sizes (some big some small) if it meant the lake was NATURALLY restocking itself with young of the year? As a family you could still go there in a couple of hours everyone will have caught multiple fish. The fishing off the dock will always be really good given the structure that the dock sits on.

I would do the sacrifice in a second. Catching 100 fish all the same I think would get boring after awhile. At least you could have a sandwhich and a drink inbetween..

[BeeGuy]

Originally Posted by freeones

Great info Chubdarter. That's the kind of thing you can make informed decisions with.

Here's my take on it -

Everything is just fine, and while it's going to change over time, it's going to be just fine in the future too.

The best news to come out of that is that there is successful spawning and replacement in PCR. That's good evidence that the walleye population in PCR can be self sustaining at some level. Probably not at today's level, but that level is artificial, and could likely be maintained through periodic stocking.

IMHO, this boils down to exactly what a few others have talked about - overall biomass and the quality of the lake itself. No matter what "solution" is proposed, there's very little that can be done about those factors, they're fixed and finite.

The relatively low recruitment numbers speak more to the forage base and quality of the reservoir habitat than anything else. Like any other ecosystem, it's working toward balance. Every doe in the herd doesn't have twins after a particulary harsh fall and winter, and if the spring/summer are brutal, it's the fawns that are first to die. I don't see the walleye population being any different. When the stocked age classes begin dieing off, then recruitment will step up to help fill void left in the available biomass.

Stocking forage, having a limited harvest, changing the structure of the lake, etc... will all have major effects on the ecosystem. In a relatively fixed system like PCR, those are all short term fixes aimed at a particular goal - to increase the size of the walleye population at the expense of the overall numbers of walleye. I don't agree with that line of thinking, not every lake needs to be managed as a "trophy" fishery, and furthermore, I don't think every lake can be managed that way. PCR isn't much more than big slough, it's never going to be a true trophy walleye fishery.

I wouldn't screw around with it if it was me, nature will take care of it itself, and those wanting fewer numbers and bigger fish will get their way eventually, just by doing nothing.

Great post. What you are talking about perhaps without realizing it is "Population Ecology".

Over-population has some pretty typical outcomes.

[freeones]

Originally Posted by horsetrader

Sorry but if you read the information you will see the numbers are going up but the size is not so what you will end up with is another stunted walleye fishery until it dies. Without a proper food source the fish will not increase in size and reproduction will be minimal.

I read the information. I just don't agree with you regarding how that information is interpreted.

The lack of growth is directly related to the forage base, size, and quality of the water body, I think everyone would agree on that. Put a walleye fry in your fish tank at home, and no matter what or how much you feed it, it isn't going to grow to be a 10lber. Reproduction is limited by the same factors. There won't be a big recruitment year class until there's room in the lake for them to actually compete and survive.

The fishery won't die. It won't stay the same as it is today, but it's not going to die unless it's opened up to unregulated harvest. There is natural reproduction, and the lake has proven that it is capable of sustaining a walleye population. It will find it's own equillibrium, likely one closer to what those who support monkeying around with it want anyway.

I agree it's a stunted walleye population. The difference is, I'm OK with that. If I want to catch fewer bigger fish, I go to a different lake, there's tons of options available for that. If I want to go with kids and catch 100 small ones, I go to PCR. It's a unique lake, and it has a place as is, despite those who wish to change it to meet their definition of a "good" fishery.

[freeones]

Originally Posted by BeeGuy

Great post. What you are talking about perhaps without realizing it is "Population Ecology".

Over-population has some pretty typical outcomes.

Thank you.

I'm well aware of it, and I'd like to think I have a pretty good understanding of what the limiting factors are and how it will play out long term. The stocking of millions of walleye in a new, previously uninhabited reservoir is going to take a while to sort itself out.