04-28-2005, 07:55 AM
Gotta lighten this one up...
Ok... for those that want to "play" with population dynamics, download this
[url "http://www.kovcomp.com/wator11.zip"]http://www.kovcomp.com/wator11.zip[/url]
unZIP it and run it. It's a very simplistic view of the predator prey relationship, but it's kind of fun to play with. Pay particular attention to the cycles on the population graph and note the relationships you see. You'll see the basic tenants of the predator prey relationship displayed there. Watching the waves in the age class graph is pretty cool too.
You don't have many parameters to play with but breeding age is one of them and you have to work with what you've got. FishBase.Org says Yellow Perch will double their population size in 1.4 - 4.4 years and Walleye in 4.5 - 14 years. I'm not sure how accurate the numbers are but it's the best I could come up with without much work and we're just playing with this thing anyway right. Take the averages of those two ranges (2.9 and 9.25 respectively), round them off, and plug them into breeding age. Because were talking in units of years for breeding age, I think 1 year is more then reasonable for Walleye starvation time don't you. Start with whatever initial population sizes you want and run it. If the whole thing doesn't go bust quickly it will stabilize as indicated by the predator/prey graph and continue to run for a long time. Want to simulate a bad year (disease, low reproduction, whatever) for one or the other, lower the initial number to half or even a quarter of the other, initialize a new simulation, run it and see what happens. Like I said, it's a simplistic view of the predator prey relationship but it is kind of fun to play with and the basic relationship is simulated.
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Ok... for those that want to "play" with population dynamics, download this
[url "http://www.kovcomp.com/wator11.zip"]http://www.kovcomp.com/wator11.zip[/url]
unZIP it and run it. It's a very simplistic view of the predator prey relationship, but it's kind of fun to play with. Pay particular attention to the cycles on the population graph and note the relationships you see. You'll see the basic tenants of the predator prey relationship displayed there. Watching the waves in the age class graph is pretty cool too.
You don't have many parameters to play with but breeding age is one of them and you have to work with what you've got. FishBase.Org says Yellow Perch will double their population size in 1.4 - 4.4 years and Walleye in 4.5 - 14 years. I'm not sure how accurate the numbers are but it's the best I could come up with without much work and we're just playing with this thing anyway right. Take the averages of those two ranges (2.9 and 9.25 respectively), round them off, and plug them into breeding age. Because were talking in units of years for breeding age, I think 1 year is more then reasonable for Walleye starvation time don't you. Start with whatever initial population sizes you want and run it. If the whole thing doesn't go bust quickly it will stabilize as indicated by the predator/prey graph and continue to run for a long time. Want to simulate a bad year (disease, low reproduction, whatever) for one or the other, lower the initial number to half or even a quarter of the other, initialize a new simulation, run it and see what happens. Like I said, it's a simplistic view of the predator prey relationship but it is kind of fun to play with and the basic relationship is simulated.
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