Originally Posted By: gvbest
Originally Posted By: SeaDNA

Originally Posted By: JohnQ
Originally Posted By: SeaDNA
I read through the study and it states that the largest source of predation is most often squawfish but that it does vary a bit by season. It also points out that bass and walleye predation are non-neglible. HOWEVER, it's s study only on predation, it doesn't talk about the other effects up and down the food web of having these non-native species in our waters.

In general, the history of non-native species introductions is terrible in many areas and for many species. I just can't see a good justification for wanting to keep these fish around.


Actually your reading of the study did not include the trapping/netting, i.e., locations based upon walleye migrations (they do do that to spawn), the timing of the migration, i.e., position in the river in relationships to the timing and locations of downstream migrating salmonoids -- Totally in different areas at different times. Hence the "Enhancement of Salmonoids."

Now exactly where are your studies that back up you OPINIONS?? Thought so, in the cave where the sun don't shine.


First of all - bite me. rofl
Secondly, you've stated your opinion that my reading did not include - I did read the damn thing. All I'm saying is that study is based on the distribution of predator fish and estimates of their consumption of salmonids. It does not look at other species eaten by the predators or their offspring which may or may not contribute to the salmon diet. It also doesn't look at the impact of these non native species on the diets of other species in the river. It doesn't look at a whole bunch of factors that could be relevant to the impact of the non-native species on the eco-system into which they were introduced. So, it's a bit premature to conclude that walleye are good for salmon from this data alone.

As for my opinion that there's a long history of disastrous unexpected effects due to the introduction of non-native species, that's not an opinion, it's a fact.



I guess you missed the part about the what makes up the vast majority of a walleye's diet.


I guess you missed the big picture of what I said. No I did see the part about walleye eating squawfish. So I should have been more clear. What I didn't see was any mention of the non-fish portion of any of the non-native species' diets and anything about how that might connect to the greater food web up and down the food web. Yes, squawfish eat salmon and walleye eat squawfish. No that is not confirmatory evidence that walleye are good for salmon. The point is that this study is limited in what it looks at. For example do walleye or bass fry compete for other food with salmon fry? This study doesn't say anything about that.


Edited by SeaDNA (10/16/12 12:58 AM)