Quote:
Originally Posted by MathGeek
Your statement about more food always leading to plumper fish seemed quite global:
Since there are well-known counter examples on planet earth, it seemed worthy to point them out. Why would spotted seatrout not be subject to the same balance sheet considerations of every other fish species? To gain weight, the caloric intake must exceed the calorie requirements. More food is not enough if the energy requirements increase by more than the energy intake. This would be true on every planet, and for every fish species on planet earth.
We've been looking through the data and analyzing in more detail. One notable fact is that there are almost always high flow conditions (full moon, new moon, high water behind weirs) when more than 40% of the gate area is opened. It would be useful to know what current speeds are present at the weirs under these conditions, and how these current speeds compare with the naturally occurring current speeds in the estuaries over the past few thousand years.
If the freshwater trout energy expenditures can be strongly impacted by the same current speeds they have seen continuously for thousands of years, it would stand to reason that current speeds much higher than Gulf inshore species have seen for thousands of years could also have a big impact on energy expenditures. Natural selection has done its job preparing freshwater trout for stream current conditions, but natural selection may not have made inshore species well adapted to the current conditions present at the weirs.
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i hear you and my original comments were just in response to you asking for some hypotheses to why which I think are very plausible. I think the weir openings correlating to thinner fish in a system that is almost 80 square miles is pretty unplausible especially when the weirs are not stopping all bait from getting through.
There are likely several factors if not 10 or 20 that are contributing to thinner fish. A correlation does not = causation.