SS1.06 The Ecological Impacts of Pelagic Longline Fisheries
Date: Monday, June 10, 2002
Time: 3:00:00 PM
Location: Carson A
 
WormB, Dalhousie University, Halifax, Canada, bworm@is.dal.ca
Lotze, H, K, Dalhousie University, Halifax, Canada, hlotze@is.dal.ca
Myers, R, A, Dalhousie University, Halifax, Canada, myers@mscs.dal.ca
 
ECOSYSTEM CONSEQUENCES OF PREDATOR DEPLETION IN THE OCEAN
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Experimental work in lakes and coastal marine systems suggests that the removal of predators can have cascading consequences across the entire food web, with implications for species diversity and ecosystem functioning. So far, it is not clear how the concepts that emerged from these studies can be applied to the continental shelves and the open ocean, which cover more than two-thirds of earth's surface and support most of the world's fisheries. One major reason for this is that these systems typically cannot be studied using powerful experimental techniques. Using case studies from shelf and open ocean food webs, we illustrate how cascading food-web effects can be detected in open marine ecosystems. Meta-analysis of large-scale food-web alterations conducted by fishing fleets is used to identify critical interactions among species across trophic levels. Moreover we identify those assemblages that are likely to be the most vulnerable to predator depletion. Increased empirical research is needed in order to quantify the consequences of strong human impacts on some of the least known, most extensive food webs on our planet.