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Coastal Fishery off of South America resides at an upwelling zone. This upwelling goes through cycles during ENSO cycles. Mortality rates were highest during EN events (Hernandez-Miranda, 2006). There is a chance that there could be a long toward shift in the climate towards the EN, which would most likely have a negative effect on fish populations (Collins, 2005). Another evaluation predicts global warming will ultimately lead to longer and weaker ENSO cycles. This occurs via complex interactions between currents and atmospheric circulation. If the first case occurs and the system shifts in the El Nino spectrum, then the fish populations in this region stand to be much lower than would be expected otherwise (Zhang, 2005). In the 1990's this region underwent several mild to moderate EN events, without intervening LN events (IPCC, 2001), perhaps indicative of the first case.
Temperature anomolies during an el nino event (Image courtesy of CPC ENSO Main Page)
If this trend is the case then it would have to be taken into account and stricter enforcements would be needed to produce the same results that would be expected without climate change. The fisheries in these regions might also take additional hits during el-nino years, so additional protection might be required for these years. If the second case happens, then climate change will most likely play a much smaller role in the management of this fishery, and plans can be carried out without too much modification for climate change. There is an ongoing debate in Peru regarding the creation of a Marine Protected Area (Working Paper, 2004), which could possibly be used to safeguard fish populations to a greater extent than they would in other regions. ENSO is also linked to changes in weather, which have effects on the terrestrial environment of Western South America. Floods and landslides in Peru during El-Nino years cause an increased mortality rate by 40% (IPCC, 2001).
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