SCIE 1P50 Lecture Notes - Clearcutting, Ocean Current, Fisheries Management
2 Nov 2011
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Document Summary
We are placing unprecedented pressure on marine resources. Half the world"s marine sh populations are fully exploited. 25% of sh population are overexploited and heading to extinction. Predicted that populations of all ocean species we sh for today will collapse by the year 2048. Fishing practices kill non target animals and damage ecosystems. By-catch = the accidental capture of animals. Longline shing kills turtles, sharks and albatrosses. Figures on total global catch do not relate the species, age, and size of sh harvested. As shing increases, the size and age of sh caught decline. As species become too rare to sh, eets target other species. Reduction in larger predator sh simplify trophic feeding relationships. 10-year-old cod, once common, are now rare. Shifting from large, desirable species to smaller, less desirable ones. Salmon sheries in bc now in severe decline. 2009 numbers indicate a 90% reduction if the frazer river salmon catch.
