SUMMARY

• Main Authors: Yasuko Semba, Takayuki Matsumoto, Hiroaki Okamoto, Toshiyuki Tanabe
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.524.6078; http://www.iccat.int/documents/cvsp/cv064_2009/no_7/cv0640702674.pdf

This document summarizes the data collected in the Japanese scientific observer program for the longline fishery in the Atlantic Ocean conducted from September 2007 to February 2008. In the 2007 fishing year (FY), eight trips (422 operations and 1,010,017 hooks) were observed. The majority of the observations were conducted in the North Atlantic. The number of observed species and individuals was 59 and 12,281, respectively. In the North Atlantic, blue shark was the most dominant followed by tuna species (mainly albacore and bluefin tuna). Except for blue shark, Atlantic, albacore was the most dominant species in the central North Atlantic, while bluefin tuna was the most dominant in eastern and western North Atlantic. In general, more species were observed in the southern area (off Florida and the tropical area) than in the northern area (off Ireland, central North Atlantic, Grand Bank). The survival rates (percentage of the species caught alive) of catches were usually high for sharks, moderate for tunas and relatively low for some billfish. The survival rates were relatively higher in northern areas and lower in southern areas. A regional difference in sex ratio was observed for many species. Females were dominant in southern areas and males were dominant in northern areas for most of the species. The length frequency distribution showed that large individuals were more frequently seen in southern areas for many species such as bluefin tuna, bigeye tuna, yellowfin tuna and blue shark. RÉSUMÉ