Remotely sensed oceanographie patterns and variability

RESUME Data from the Japanese longline bluefin fishery in the Gulf of Mexico for 1979 and 1980 were combined with in situ oceanographie data from four research cruises and several ship-of-opportunity XBT transects, and with infrared and visible ssatellite imagery from GOES, TIROS-n, and NIMBUS-7. Catch per unit effort, CPUE, for Atlantic bluefin tuna (Thunnus thynnus thynnus) in 1979 was approximately one third that in 1980 and appears to be associated with the area fished. Using GOES infrared data, the boundary of the Gulf Loop Current was located and compared with the CPUE; the high 1980 catch was correlated with proximity to the surface thermal front of the current and appears to reflect a change in fishing strategy between years. Correlations with other environmental factors such as sea surface temperature, tempera­ ture differences, time (spectral estimates), and configuration of the Loop Current, were generally inconclusive. Polar orbiting satellite data, with at most twice-per-day observations, provided very few useful current boundary locations whereas GOES, with its hourly imagery schedule for oceanographie features, allowed comparisons almost every day during the fishing season. Operational application of satellite data to fisheries oceanography in the tropics and sub-tropics requires the high imaging frequency of geostationary vehicles because of cloud abundance, separation, and advection rates.