Tom, When Kenny Rose and I were doing such models as parts of larger IBMs for YOY fish with flounder, yellow perch, walleye etc. we made the assumption that in relation to the swimming speed of a YOY fish, a zooplanktor's movement was essentially nil. Thus in our enounter rate models we only considered the speed at which the forager moved and didn't worry about the movement of the zooplankton. I don't think that any of our reviewers had any prolem with that assumption. If you're unwilling to accept that assumption, I think that you could make a reasonable assumption of zoop moving at one body length per sec. For zoop, then that would give you swimming speeds of about 0.5 to 5.0 mm/s depending on the size of your zoop. If you use the Gerritsen & Strickler (1977) equations to calculate an enounter rate (see also Bailey & Batty 1983 or a version that is in one of my recent papers, Tyler & Rose 1997, J.Anim.Ecol 66:122) then I think that you'll find little difference in encounter rates if the range of prey movement is 0.5 to 5.0 mm/s.
cheers, Jeff
On Fri, 13 Jun 1997, Thomas Miller wrote:
> I am trying to model encounter rates of YOY fish with their prey > and am finding myself limited in the number of zooplankton prey taxa that > I can find information on swimming behaviour. Any suugestions on > references I might look at would be appreciated. > > If you reply to me directly, I will post a summary to the list at > a later date. > > Thanks in anticipation > > Tom Miller >
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