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12/12/2022 2:29 pm  #1

Invasive species spiny waterflea alert

Saw that there is now an alert for spiny waterflea for Kioshkokwi Lk., Manitou Lk., and North Tea Lk. I presume this invasive species will continue to spread. Kinda sad that there will likely be adverse effects to the fishery & ecosystem in Algonquin. I hope we're not the generation that talks about the good old days before the fishery collapsed.


12/13/2022 8:28 am  #2

Re: Invasive species spiny waterflea alert

Does anyone have a link to the 'alert' in question. Is it an alert to its threatening spread or to its confirmed spread?

Here's a link to a descriptive reference on the 'spiny waterflea' ...


12/13/2022 8:56 am  #3

Re: Invasive species spiny waterflea alert

I found nothing in a couple google searches. 

The data associated with the spiny waterflea indicates a 30-40% reduction in the native zooplankton species.  While this is hardly a 'fishery collapse", I don't see this statement validated with any reference to scientific study through several links including government websites, so this could be a phrase invented by some ecological activist that has found its way into policy-guiding documents.


12/13/2022 6:28 pm  #4

Re: Invasive species spiny waterflea alert

Hi Barry,

The alert appears when generating a paddling reservation as per the text below:

Everyone can prevent further invasions into Algonquin Park by inspecting and wiping down all boating and angling gear before travelling to another waterbody.For more information, including how to recognize Spiny Waterflea, please see:Canadian Council of Invasive Species
[url=,orange%2C%20blue%20and%20green%20colouring]Ontario Invasive Species – Spiny & fishhook water flea[/url]
Thank you for helping to protect the unique aquatic ecology of Algonquin Park.

  • Spiny WaterfleaAlgonquin Provincial Park is home to some of the most unique aquatic ecosystems in Ontario including populations of Brook and Lake Trout. Sadly, these aquatic ecosystems, and the fish within them are under threat. Spiny Waterflea (Bythotrephes longimanus) is a non-native zooplankton that disrupts natural food webs and has recently been detected in Kioshkokwi Lk., Manitou Lk., and North Tea Lk. Spiny Waterflea can travel between waterbodies on angling and boating gear including canoes and kayaks. Please avoid fishing in these lakes before travelling to other parts of the park.

  • Not sure what the purpose of the 2nd URL link is though as it just directs the user to a another Reservations page with the same alert and no further details.



Last edited by hiker72 (12/14/2022 6:23 am)


12/14/2022 10:35 am  #5

Re: Invasive species spiny waterflea alert

PaPaddler wrote:

The data associated with the spiny waterflea indicates a 30-40% reduction in the native zooplankton species.  While this is hardly a 'fishery collapse", I don't see this statement validated with any reference to scientific study through several links including government websites, so this could be a phrase invented by some ecological activist that has found its way into policy-guiding documents.

The risk of fishery collapse is due to spiny waterfleas not being edible by the native species that rely on the native zooplankton as a food source. The spine on the spiny waterfleas is an effective defense mechanism against being eaten themselves. This is mentioned on the Invading Species page but it could be better highlighted:

The 30-40% reduction in native zooplankton is a disastrous reduction in the food supply for native species and would easily trigger a fishery collapse requiring a corresponding 30-40% reduction (at least) in harvest rates of sport fish to try and maintain the much reduced native populations. Of course there is a risk of much greater damage to native sport fish populations in the time between the spiny waterflea colonizing a waterbody and the invader being detected. 


12/14/2022 11:18 am  #6

Re: Invasive species spiny waterflea alert

@ RobW:  I would not agree first with the term 'fishery collapse' and secondly with the inedibility of spiny waterfleas (some species thrive when the spiny waterfleas reach high levels - admittedly, not fish like speckled trout except in the earliest stages of life!).  The small amount of research I've reviewed (a few of the articles from this google scholar search: ) does not make reference to fishery collapse and tends to assess the impact on native zooplankton and other water fleas, specifically.  Most of the publications appear to identify that our knowledge on the matter is hindered with a limited amount of information on pre-existing zooplankton levels and subsequent effects after the invasive species is detected.

I don't doubt that the impact would be 'negative' in our view - changing the lake fauna in a way that we perceive as detrimental.  But I also don't believe the existing research makes a clear distinction of the predicted outcomes as a 'collapse'.  An excerpt from one of the hits on the search cited above clarifies that there are many unknowns due to a lack of research and information:
"The complexity of  these factors suggest that we may not be able to predict the possible impacts of the co-occurrence of Bythotrephes and declining Ca on zooplankton in any particular Canadian Shield lake with confidence. Nevertheless, on average, and in lakes with both stressors, we expect to see the loss of large daphniids such as Daphnia pulicaria, a key herbivore in the aquatic food web. Over time, we expect the loss of other daphniids (e.g. Daphnia retrocurva and Daphnia dubia) and small cladocerans, with lake communities dominated by Holopedium glacialis and/or copepods. Indeed, we have some field evidence that these changes are indeed occurring (e.g. Jeziorski et al. 1015 2015)."

In the end, let's hope we gather greater knowledge and understanding of the scale of the impact and, more importantly, how to limit or eliminate potential risks!

Last edited by PaPaddler (12/14/2022 12:32 pm)


12/17/2022 11:36 am  #7

Re: Invasive species spiny waterflea alert

I'm definitely not a spiny water flea expert, in fact I had never heard of it until I saw the alert.

However in general, I do think that we hugely misunderstand how finely balanced nature is. Small changes can create huge disruptions over time. A 30-40%, reduction in say food supply to smaller fish might not simply mean let's reduce our catch by 30-40% of adult adult sport fish.

I guess what had particularly alarmed me as I googled what this spiny water flea was, is this story referencing the Walleye collapse in Mille Lacs.

Now I recognize this is just a website article, did not reference peer reviewed journal articles etc, but I do find it alarming. Who knows maybe only the Walleye fishery is severely affected, or maybe there was something else adversely affecting Mille Lacs & the combination with the spiny water flea tipped the balance.

The reality is that nature is in a very fine balance. Even very small changes have huge changes over time. For example if the average woman goes from having 2.1 babies to 2.0 babies, we could say that is a small 5% change, but the result could go from stable population to a steadily shrinking human population & not just 5% less humans (as 2.0 is not enough to account for early deaths, accidents, etc).

So reading about 30-40%, reduction in native zoo plankton, does alarm me. Maybe this results, in non-stable population reproduction rate for particular lakes & particular species of fish. I do hope my alarm is unfounded & hope people take the threat seriously & prevent further spread, so we don't generate real world data to find out how bad (or not) this spiny water flea is.

     Thread Starter

12/19/2022 7:24 am  #8

Re: Invasive species spiny waterflea alert

Good points, SeekingSolitude.  I expect we all share the same concern with protecting the environment we are familiar with. 

While nature appears to be finely balanced, it is incredibly robust and pervasive in finding a way to adapt and exist.  Ice ages that scour the landscape and snuff out nearly all of the fish from their lake/river habitats, meteorites that liquify the rocks of the crust and ignite the atmosphere (like in Sudbury), volcanoes that poison the atmosphere with acidic gasses - these are examples of the mega-dynamic changes that nature has adapted to in the past.  

This doesn't give me a pass to conclude 'human damage doesn't matter' but it does demonstrate the incredible adaptive ability that nature has...and has demonstrated on this planet for nearly four billion years.  What I find objectionable are conclusions that don't fit the data - and the media is full of conclusions/opinions designed to influence our beliefs to support their agenda.  It likely will never go away since both love and deception are innate in our species, but be aware that what we read may be related to truth or may represent someone else's 'truth'.

In truth, I'd rather be fishing. ;-)


12/19/2022 11:27 am  #9

Re: Invasive species spiny waterflea alert

You need to understand the definition of "fishery". This page is a good starting point:

In the case of Algonquin, discussion of the fishery is a discussion of the sport fishing fishery which includes specific species particularly the native trout populations but also walleye, bass, muskie, and pike populations. The trout populations would be the most significant species in that discussion. 

A 30-40% reduction in food sources would undoubtedly lead to the collapse of the sport fishery in Algonquin. Yes there will still be fish. Some species may benefit, but they won't be the sport fish species. Yes nature is robust and ecosystems are continually evolving and adapting, but if those changes result in cutting the sport fishery populations in half or worse, then the fishery that exists today will have collapsed.  

You also need to understand that scientific paper have a specific scope, state conclusions based on statistical analysis, will always state conclusions in terms of probability, are required to acknowledge the limitations of the research, and are expected to identify areas for further research. This means that a paper looking at the impact of spiny water fleas on zooplankton populations is not going to make statements about the sport fish populations since that is out of scope for the paper. Nonetheless you can apply extensive, established knowledge of how prey populations impact predator populations to state reasonable hypotheses to be evaluated with further research. Since this is science, the procedure is to design an experiment that controls for variables and generates the necessary data to be evaluated with a statistical model. It also means that a study on a single lake or small set of lakes will acknowledge that the research is insufficient to make 95% confidence level or higher statements about a random other lake. Again, since it is science the fact that other variables (pH would be an obvious one, specific nutrients another, ... ) may (likely will) impact the success of the spiny water flea in different lakes. 



12/20/2022 8:03 am  #10

Re: Invasive species spiny waterflea alert

@RobW thank you for identifying all the things you believe I need and certainly for the link that supports your point and informs of the definition of fishery.

Here's a bit of unsolicited feedback:  you might consider using a different phrase from  "you need" as it comes across as a bit condescending and domineering.  Maybe it's just me and the way I read it, but if I were to reply with "You need to understand that there is no evidence linking fleas and fishery collapse" it might be interpreted negatively by you.

I'm not committed to this subject and am certainly no expert as well, but I have spent over thirty years in the medical field (although I only have an undergraduate degree in physics) and have a robust understanding of the design, intent, interpretation, limitations and potential flaws of peer-reviewed published research.  I did a cursory search in google scholar and did not find any papers that link the spiny water flea introduction with fishery collapse (a distant link, I get it).  The point I am trying to make is, it is a leap of faith to project 'undoubted fishery collapse' from water flea introduction as a causal relationship.  I'm not arguing the 30-40% reduction of native zooplankton wouldn't have an impact, I'm arguing that linking an extreme, subjective conclusion that isn't supported by the evidence wouldn't stand up to scientific scrutiny. 

We often see this type of statement in areas where one stands to profit from it:  like extra clicks on a news story that inflates the information with dramatic terms like 'collapse' or 'chaos'.  


12/20/2022 10:03 am  #11

Re: Invasive species spiny waterflea alert

Well PA, in Ontario the relationship of organisms in the food chain is covered in Grade 4 - 

By the end of Grade 4, a student is expected to have a basic understanding that if  organisms are removed from the bottom of the food chain then there will be a definite negative impact on apex predators at the top of the food chain. When a large proportion of organisms at the bottom of the food chain are removed - say 30-40% - it will have a large impact. 



12/22/2022 9:21 am  #12

Re: Invasive species spiny waterflea alert

Thanks, Rob.  Really helpful.


5/31/2023 4:25 pm  #13

Re: Invasive species spiny waterflea alert

Currently watching a just released video from Kevin callan on a trip through north tea. He talks about the water flea and the park recommendation to clean your boat when travelling from the lakes the flea is found in, as well as cleaning your fishing gear to reduce the risk of tranferring the flea out of the infected lakes. I feel like this flea is going to be across the park pretty quickly.


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