Overfishing Changes

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Pages: 3

Predicted Changes to British Fish Stocks by 2100

Global fish stocks face crisis: a combination of overfishing, pollution, environmental change, and habitat destruction are predicted to lead to the collapse of all fish and seafood species by 2048 (Worm, et al. 2006). The increase in the human population during the 20th century and the range of new and efficient methods for harvesting our seas have bought us to a point where 70% of global fisheries are now being fished beyond their capacity.
By the 1980s, 100% of British fish stocks were being fished unsustainably. There has since been some improvement, however mature fish are not being allowed to thrive in sufficient numbers to allow populations to regrow (Holmes and Armstrong 2010). The
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The fishing methods employed by the British fleet are largely unselective and have the potential to bring in massive catches. Seine nets are used to encircle entire schools before being pulled shut into a fully enclosed “purse”. Longlines hook epipelagic fish, birds, mammals, and reptiles. Trawls tear up the seabed, destroying the benthic infauna and epifauna, and disturbing the substrate. The majority of the waters surrounding the United Kingdom are bottom trawled multiple times a year (Kurlansky 1997). Seamounts are particularly slow to recover after periods of trawling; their isolation acts as a barrier to recolonization. Resistant species and early colonizers rapidly become dominant, unbalancing the ecosystem. Due to the slow growing nature of soft corals and the increasing issue of ocean acidification, the system may remain at this early stage of succession for long periods (Williams, et al. 2010). Drift nets entrap a variety of marine taxa, and along with longlines and seine nets can continue to “ghost fish” when lost. In low visibility, synthetic nets can maintain a high catch for a long period of time, with the initial victims acting as bait for larger species (Matsuoka, Nakashima and Nagasawa …show more content…
This has created a situation where despite a lower abundance of fish annual catch is increasing. We currently measure fish stock fluctuations using Landings Per Unit of Power (LPUP). The LPUP of British bottom trawling fleet has declined by 94% over the previous 118 years (Thurstan, Brockington and Roberts 2010). Although we are not landing fewer fish than a century ago, the effort and expenditure needed to catch those fish has increased to the point where fishing on an industrial level may soon become economically