One of the primary constraints is that climate forecasters have relatively poor skill in predicting sea surface temperature (SST) and thermocline depth near coastal areas due to the steep gradients in oceanographic as well as bathymétrie properties, compared to the open ocean areas. Thus, it may be difficult for regulators to plan their closed seasons and scientific cruises with much precision because of this temporal and spatial uncertainty. One of the factors preventing the more accurate prediction of ENSO impacts on the coastal ecosystem of Peru is the lack of regional
scale (e.g., coastal) observations. Enhanced observations, combined with the targeted training and further model development, would aid in the monitoring and prediction of changes in coastal environmental conditions. Further, even if there were perfect climate forecasts (an impossibility), there remains the difficult step of incorporating such information into fisheries models (Glantz, 1979).
In addition to climate there are numerous variables that impact fish populations, including fishing pressure. Year-to-year and multitimescale variability in stock abundance during non-ENSO years is still not well understood (Bakun, 1996; Sharp and Csirke, 1983; Kawasaki et al., 1991; Lluch-Belda et al., 1992). One example ofhow this uncertainty is played out in real decision making is highlighted by the two options that were being debated during the 1997-1998 ENSO event. On the one hand, at the start of the event, conservationists called for a halt to all fishing in order to preserve as many anchovy as possible in the hope of preventing a future total collapse of the fish population. A complete ban on fishing, of course, has massive social implications, including widespread unemployment, loss of export dollars, and ensuing political unrest. This regulatory move may be rationalized by claiming that it is an attempt to ensure resources for current as well as for future generations. On the other hand, as it became clear that an extremely warm event was underway, some argued, not without reason, that fishing regulations should be removed and the fishermen should be allowed to catch what they can before all the fish disappear for "natural" reasons. Again, an arguably "rational" position, albeit self-serving, based on past experience during extreme ENSO events.
To decide the best option between these two possibilities (or a combination thereof), there is a need for more reliable forecasts as well as improved fisheries population dynamics models. Only recently have meteorologists, biological oceano-graphers, and fisheries biologists begun to join forces on these problems. During the 1997-1998 event, the Peruvian authorities followed a more politically viable middle ground, by exercising what can be considered "adaptive management" practices, i.e., adjusting their standard regulatory measures based on increased observations and sampling, allowing them to set their closed fishing periods with greater flexibility in response to a changing environment and political pressure.
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