Blair, since you were also at the meeting, I have sent an email directly to Jessica, Mike and other bio's as follows:
"Hello,
I attended the Edmonton Trout Club meeting on the evening of Jan 16, 2018 and would like to request clarification on the modeling tool explained in regards to the FSI or Fish Sustainability Index that was presented.
In the presentation, the initial explanation regarding how the FSI index was used to determine potential threats to our Native fish stocks – specifically regarding the North Central Trout Recovery Program.
In the explanation of how this model worked, the example given was as follows:
The first variable used in the initial example was water temperature. I believe the temperature noted in the example was 13 degrees which correlated to a score of 4.2 out of 5.
The second variable that was given was a mortality rate of 1 out of 5 fish – or 20% mortality rate.
The FSI score that was derived from this simple example was shown as 0.8 – or 4.2 multiplied by 20% equally 0.8 as your scorecard for the FSI.
If this is truly the way the model is working, I would like to request further clarification as I believe the example meant to derive the sustainability or mathematical probability of the fish surviving under said conditions.
The model should have calculated out a FSI as follows: (4.2 x (1-0.2)) which would give the probability of survival or in this example a score of 3.36 (or3.4 with rounding). I understood that the FSI index was trying to determine the survival rate.
If the model is using the probability of mortality in error to calculate the survival rate, then the model is wrong. The modeling tool should instead use the probability of surviving, not mortality. The modeling tool would be fundamentally incorrect and would need to be re-configured to extract useable or reliable data. If the example given is how the model calculates, then you are placing a significantly higher weighting on the catch and release mortality rate which would explain why you think catch & release is not sustainable. In this example, four times the weighting.
I am requesting clarification please. I have grave concerns that this management technique places far too much emphasis on what you refer to as Overfishing and will only serve to put more pressure on the remaining fisheries left open.
Before you enact such a large change, please ensure your modeling technique isn’t fundamentally flawed as shown in the presentation. The entire basis of the assumptions used would be incorrect.
A VERY concerned Albertan and fisherman……."
I am waiting for a reply.
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