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Fishery Bulletin 89(3). 1991 



1 



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Date 



Figure 4 



Daily percentage of longline sets that caught one or more 

 yellowfm tuna in the Gulf of Mexico. Curve is fit using robust 

 locally-weighted regression. 



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Date 



Figure 6 



Percentage of cloud-free water pixels used to derive sea- 

 surface temperatures from Advanced Very High Resolution 

 Radiometer satellite images used in the study, 1986-88. Curve 

 is fit using robust locally-weighted regression. 



35 



° 30- 



C 25 



3 



C 20 



f 

 O 15 



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SEP87 NOV8? JAN88 



Figure 5 



Daily mean yellowfin catch/1000 hooks in the Gulf of Mexico, 

 1986-87. Straight line is overall mean yellowfin CPUE. Curve 

 is fit using robust locally-weighted regression. 



Image database 



The regression analysis of satellite-derived SST with 

 the buoy SST data showed acceptable agreement 

 between the two temperature values (r 2 0.902, n 206; 

 Fig. 7). There was some tendency for SST from 

 satellites to be lower than those from buoys at the 

 higher temperature ranges, with the imagery acquired 

 by NOAA-10 satellite accounting for most of the 

 variation. 



The geographic region in this study, excluding land, 

 covered 1,512,272 ocean surface pixels. Cloud cover 

 and/or the position of the satellite track reduced the 



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Date 



Figure 7 



Mean satellite-derived sea-surface temperature (SST) for the 

 Gulf of Mexico derived from Advanced Very High Resolution 

 Radiometer imagery, 1986-88. Curve is daily mean surface 

 temperature recorded at National Weather Service data buoy 

 42001, located at latitude 25.9°N, longitude 89°W. 



number of pixels available for analysis in each image. 

 Image coverage of the study region ranged from less 

 than 1% to 70% of the available pixels, with no seasonal 

 pattern to the coverage (recall that summertime images 

 were generally excluded from the analyses) (Fig. 6). 

 Figures 6 and 7 also portray the temporal coverage of 

 the imagery used in our analyses. The mean image-wide 

 derived SST and the daily mean surface temperature 

 recorded at the National Weather Service data buoy 

 42001 (latitude 25.9°N, longitude 89°W) both follow 



