Biological Oceanography in awarming world• How do we knowit’s warmer?• Local consequences• Global ImpactsFishingPressure• Before 1950, >90% of fish caught were forhuman consumption• Since 1950, world fisheries increased 6X,but only 5% of fish go to feed humanpopulations (as fish)Fishing and theFood Chain• To assess thisscientifically, we canassign a trophicvalue to eachorganism• Sustainable fisheriesgenerally start withlow valuesTrophic Status of FisheriesRise of thePeruvianAnchovettaFisheryEl Niñocollapse ofthePeruvianFisheriesMyers, R.A., and B. Worm. 2003. Rapid worldwide depletion of predatory fish communities. Nature 423: 280-283.Demise of the Big Fish?Myers, R.A., and B. Worm. 2003. Rapid worldwide depletion of predatory fish communities. Nature 423: 280-283.Number of Large PredatorsLong Term Over-exploitationScience. 2001 July 27;293:629-639.Long Term Over-exploitationScience. 2001 July 27;293:629-639.Towards Ecological ExtinctionScience. 2001 July 27;293:629-639.Science. 2003 Aug 15;301(5635):955-8.“This complex response of phytoplankton abundance to SSTprobably arises because temperature not only affects biotadirectly, but also acts as a useful proxy for other physicalprocesses regulating the size structure, taxonomiccomposition, and abundance of phytoplanktoncommunities. For instance, seasonal and regional changesin vertical stratification and nutrients are often associated withchanges in SST. In the Northeast Atlantic, there is also astrong relation between winds and SST, particularly westerlywinds that are important for mixing and stratification, a likelyconsequence of the large-scale atmospheric forcing by theNorth Atlantic Oscillation (NAO)” --Richardson & Schoeman,Science 2004Our findings suggest that any effects ofsuch climate change will have an impacton phytoplankton, copepod herbivores,and zooplankton carnivores, therebyaffecting ecosystem services, such asoxygen production, carbon sequestration,and biogeochemical cycling. Although thedirect consequences of these changes forfisheries are not clear, it seems inevitablethat fish, seabirds, and marine mammalswill need to adapt to a changing spatialdistribution of primary and secondaryproduction within pelagic marineecosystems.--Richardson & Schoeman, Science
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