Biology 2485B Final: Bio 2485B-Lecture 12:13
13 Apr 2018
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Pressure on wild populations: half of (cid:373)ari(cid:374)e fish full(cid:455) e(cid:454)ploited (cid:894)take (cid:373)ore pop (cid:449)ould(cid:374)"t sur(cid:448)i(cid:448)e, take e(cid:374)ough(cid:895, 28% are overexploited (take more than pop support, cause extinct) Groundfish: fish that live/feed bottom: commercially favoured, characteristic of k-selected. Exclusive economic zone: nation have legal right to waters. Increase due to trawling (using large boats powered by ff, fish caught, store, frozen right on ship. Gap b/w allowed and actually harvest: overestimate how much fish could catch. Industrialized fishing depleted stocks while global catch remain stable improve tech: fast ships, sonar map, satellite fleet travel longer distance. Fish down food chain: pressure increase, size/age fish declines. Tend to harvest largest/older (cause fish to become small and mature quicker: as species become rare to fish, fleets target other species, shifting from large, desirable species to small/less desire ones. Max sustainable yield: max harvest that can be taken without depleting pop permanently. Use to manage harvest of sources taken from wild.
