Tactics of Pacific Northwest albacore fishermen - 1968, 1969, 1970

Graduation date: 1974This study examines the relationship between fishing activities\ud of Pacific Northwest albacore fishermen and the availability of albacore.\ud Tactical responses of troll-boat fishermen were compared to\ud changes in daily apparent albacore abundance. Tactical responses\ud included boat aggregation and total applied effort (number of boats)\ud within a particular area, and net daily distances traveled by individual\ud boats and the medial center of the fleet. Apparent abundance estimates\ud were derived from logbook catch records collected during the\ud 1968, 1969 and 1970 seasons.\ud Fishing power estimates of individual vessels allowed comparisons\ud to be made of the most successful and least successful boats.\ud In general, the most successful boats were larger, fished nearer\ud the fleet center, traveled less net distance each day and caught more\ud but smaller fish than the less successful boats. The magnitude of the\ud differences between the most successful and least successful boats\ud decreased progressively from 1968 to 1970.\ud Apparent abundance fluctuations were synchronous in separate\ud areas of the 1968 fishery but not in the 1969 and 1970 fisheries.\ud Fluctuations tended to be periodic in 1969 and 1970 but not in 1968.\ud No generalizations as to apparent abundance (patchiness, size of\ud albacore concentrations) could be determined among years.\ud Fishermen responded quickly to changes in apparent abundance\ud during 1968. Boats were highly aggregated on days of high catches,\ud and dispersed on days of low catches. Fishermen responses during\ud 1969 were one day out of phase with catches. Boats aggregated one\ud day after days of high catches, indicating that fishermen experienced\ud difficulty in staying on concentrations of fish. In 1970 fishermen\ud experienced no difficulty in staying on fish concentrations as record\ud daily catches were reported.\ud According to interviews and questionnaires, albacore fishermen\ud rely heavily on inter-boat communications for planning their daily\ud fishing tactics. A consequence of this reliance on radio communication\ud appears to be a greater degree of boat aggregation and less willingness\ud to scout in areas away from the central fleet area. Areas to the north\ud and south of the central fleet were shown to have high estimates of\ud albacore abundance but were exploited by very few boats. Greater\ud dispersal of the fleet and use of several survey boats are suggested\ud as a means of increasing the total fishing catch