Hello Jeffrey,
Very interesting work on the differences between northern and southern
populations of con-specifics. In addition to the idea you discussed
regarding the interaction between predation pressure and growth rate have
you considered the differences to be a response to length of the growing
season and the need to reach a critical size for over-winter survival?
i.e., fish in northern areas take more risks for feeding because they have a
shorter growing season...the following reference may be helpful if you like
this idea:
Schindler, D.E. 1999. Migration strategies of young fishes under temporal
constraints: the effect of size-dependent overwinter mortality. Canadian
Journal of Fisheries and Aquatic Sciences 56 (supplement 1): 61-70.
Cheers,
Michael Cooperman
PhD Candidate
Dept. Fisheries and Wildlife
Oregon State University
Corvallis, OR 97333
-----Original Message-----
From: Jeffrey G. Miner [mailto:[log in to unmask]]
Sent: Friday, April 19, 2002 9:32 AM
To: [log in to unmask]
Subject: Fish Data-LMB Latitudinal Differences
We have conducted a behavioral study of YOY largemouth bass from
northern and southern systems and found that northern fish are
considerably more active and consume more (when fed ad lib) than
southern counterparts. We are planning to put this into the context
of mortality- growth rate trade-offs by developing a predation index
across latitudes. To do this we need estimates of absolute biomass
of potential predators in northern and southern systems. A
literature review indicates that there is some data from cove
rotenone studies especially in southern systems, but we have found
precious little on absolute biomass estimates of predators in
northern systems (preferably from northern US and Canada - the limit
of LMB distribution). We will like to take these data, couple it
with temperature data, size frequency distributions of these
predators, size of YOY LMB, and percentage of fish in predator diets
to get a first cut at risk across latitudes.
If you are aware of grey literature (reports, state documents) or
older refereed literature containing these data (especially absolute
biomass of predators), I would appreciate hearing from you.
Thanks.
Jeff Miner
--
Jeffrey G. Miner, Ph.D.
Associate Professor
Aquatic Ecology and Fisheries Laboratory
Coordinator, Ecology-Ethology Research Station
Graduate Program in Ecology, Evolution, and Conservation Biology
Department of Biological Sciences
Bowling Green State University
Bowling Green, OH 43403
USA
(419) 372-8330 Fax: (419) 372-2024
[log in to unmask]
http://www.bgsu.edu/departments/biology/
"First they ignore you. Then they laugh at you.
Then they fight you. Then you win."
Gandhi
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