Relation between Working Time and Predetermined Working Conditions as the Basis for Seeking the Possibility of Equalizing the Length of the Working Time of a Tuna Longliner

The possibility of equalizing the length of time for daily work was, in the preceding report, eXamined usingthe records of 139 strings, which were extended along a nearly straight course and taken from 392 recordsobtained from a research tuna longliner in 2 years in the eastem mid-Pacific. These records covered 35.4% ofthe available records. The coverage of the records was increased to 90.6% ( = 355 strings) by including thoseextended along a curved or meandering course. They were classified into 23 groups with respect to position,season and gear construction. It took about 5 hours to extend a string with 2,400 hook droppers and 12.5 hoursto retrieve it on the average. The observed time length of each operation was compared with that estimated fromeither the group average of the speed or the regressive relation of the speed to the number of sections, slack inthe mainline and wind speed. Setting a difference of less than 10 min for extending work and 30 min for retrievingwork was within the permissible range, the times for extending 85.6 % of the strings and that for retrieving68.5% could be expressed by using the group average of the speed. These rates increased to 91.0% and 77.7%,respectively, when the observed time length was compared with that using the regressive relation. The stringsshowing a difference in the time length over the permissible range were concentrated in 4 groups for the extendingtime and in 10 groups for the retrieving time. The former suggested the dependence on the number of daysfishing. For the latter, the reason for the difference between these groups and others has not been clarified yet.These results suggested the possibility of equalizing the time length of daily work by adjusting the length of thestring according to the predetermined conditions.