FishingDownFW

FishingDownFW - 1 Ecological and evolutionary consequences...

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Unformatted text preview: 1 Ecological and evolutionary consequences of human activities Humans as the ultimate top predators From hooking Fishes individually Angling Hand line Demersal long line Floating long line Pelagic trawl Purse seine Bottom trawl to shing with nets Decline of global sheries over the past 50 years # of collapsed sheries = # at < 10% of historical maximum Atlantic Cod: A case study of the sh that changed the world 2 Atlantic Cod: portrait of overexploitation: Why doesnt the stock recover, even when Fshing is stopped altogether? Cod population sizes Small-scale inshore Fsheries Seasonal eets Offshore bottom trawlers Interntl. quotas; Canada EEZ Moratorium declared ishery closed indeFnitely Canadian landings of Cod (1850-present) Size at maturity Size at maturity Has there been evolution as a result of human Fshing pressure? Size at maturity Mature too young: few eggs produced ewer years of reproduction; less likely to survive to reproduce Prior to mechanized Fshing: stabilizing selection for size at maturity...
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FishingDownFW - 1 Ecological and evolutionary consequences...

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