Originally Posted by Smalls
Inferring anything based on a handful of structures doesn't make sense when the lifeform is affected by so many variables. This isn't grass we are talking about, which is affected by a handful of variables that can be quantified or qualified and manipulated quite easily. This is a highly mobile population that is affected by competition, predation, salinity, tides, moon phase, prey abundance, weather, etc. Unless you can eliminate or control all other variables, it is impossible to say that one factor alone contributes to the BMI of a species.
You can control the weirs, but can you control prey abundance, predator abundance, moon, sun, weather, tides, salinity, competition? No. So how do you know that the weirs are responsible, even partly, for the condition of the fish.
My thesis was heavy on statistics, so I know all about what they can and can't tell you. The difference is, I could quantify or qualify ever variable I dealt with. You can't do that here. You miss half the picture because of that. It's not a linear relationship, and will never be a linear relationship.
Weir openings alone do not equal thin fish or thick fish. They may correlate, but again, correlation does not necessarily equal causation.
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