It should be noted that these model predictions are the relative sizes 

 (i.e., ratios) of the oil-impacted and non-impacted catches. These ratios 

 provide a measure of the oil spill impact expressed as percent catch deviations 

 from some non-impacted average catch or expected "normal" catch. Given the 

 actual size of this baseline catch, the predicted percent catch deviations can 

 either be converted into simple economic terms by assigning a dollar value to 

 the particular species under study, or be used in sophisticated econometric 

 models to project the onshore impacts of an offshore oil spill. No economic 

 component is presently included in the model system. The projected annual 

 relative sizes of the oil impacted and non-impacted catches can be used to 

 assess the short-term impact in the fishery, while the cumulative percent 

 catch deviations over any chosen number of years may be used as an estimate of 

 the long-term impact. 



For more detailed descriptions of the model system and individual 

 submodels, the reader is referred to Reed (1980), Reed et al. (1981, 1982), 

 and Spaulding, Saila et al. (1981, 1982), Lorda et al. (1982), Anderson and 

 Spaulding et al. (1982). 



APPLICATION OF MODEL SYSTEM TO GEORGES BANK STUDY AREA: SELECTION OF CASES 



Selecting the appropriate oil spill test cases to perform is extremely 

 complicated given the number of variables in the many model components, 

 and the complex interconnections among the various submodels. Rather than attempt 

 to determine through trial and error which spills would have the greatest impact 

 on a given fishery or on the combined fishery, it was decided to select several 

 oil spill scenarios that might be typical for the area and the proposed oil 

 exploration activities. This selection process was performed after a review of 

 the literature on likely spill locations and sizes (Danenberger 1977; Devanney 

 and Stewart 1974; Moore et al. 1973). 



To investigate the sensitivity of the model system a series of simulations 

 has been performed varying spill location, spill size, oil type, and spill 

 timing. An analysis of these results suggests that spill timing is one of the 

 most critical parameters in determining impact. 



To study the influence of spill timing on impact, a series of independent 

 monthly blowout spill simulations was performed. Each discharged 68 million 

 gallons of Norwegian Statfjord Crude over 30 days. Table 1 shows a detailed 

 list of the oil spill fates input data for these monthly spill cases. Spill 

 site location, the existing OCS Sale No. 42 lease sites, and the proposed OCS 

 Sale No. 52 sites are shown in figure 2. 



Three major criteria have been used in the selection of candidate fish 

 species: (1) species which rank high in terms of commercial value and volume, 

 (2) species which have been reasonably well studied and for which biological 

 information is sufficient for building population dynamics models, and (3) 

 species for which data concerning early life history stages are available for 

 Georges Bank. Based on these considerations, Atlantic cod, Gad us morhua and 

 Atlantic herring, Clupea harengus will be discussed here. 



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