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
><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> To leave the Fish-Sci list, Send blank message to: mailto:[log in to unmask] For information send INFO FISH-SCI to [log in to unmask] ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> To leave the Fish-Sci list, Send blank message to: mailto:[log in to unmask] For information send INFO FISH-SCI to [log in to unmask] ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><> ><>
|