Excerpt from Hypotheses on the Origin of Exploited Skipjack Tuna (Katsuwonus Pelamis) In the Eastern and Central Pacific Ocean Figure 3.-percentage of females classified as maturing during each quarter of the year from various areas of the eastern Pacific (data are from Orange. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Catch data of the Japanese tuna longline fishery from 1964 to 1967 were analyzed to determine the distribution, abundance, and movement of skipjack tuna, Katsuwonus pelamis, in offshore waters of the Pacific Ocean. Large skipjack tuna, as well as larvae, were found to be concentrated mainly in the east central equatorial Pacific. Movement of skip-jack tuna stocks was determined by following the shifting of high-CPUE (catch per unit effort) cells from one quarter to the next. The apparent movement of skipjack tuna stocks in the Pacific appeared to coincide with the circulation of the major ocean currents; counterclockwise in the southern hemisphere and clockwise in the northern hemisphere, except in the eastern Pacific where the current flow is counterclockwise. The movement patterns of high CPUE suggested that skipjack tuna adults or their progeny could move from one area to the next. The movement pattern was used also to determine the probable migratory routes followed by skipjack tuna tagged in the eastern Pacific and recovered near the Hawaiian and Christmas islands.

Excerpt from Distribution, Relative Abundance, and Movement of Skipjack Tuna, Katsuwonus Pelamis, in the Pacific Ocean Based on Japanese Tuna Longline Catches, 1964-67 Certain characteristics of the longline gear affect the catch and catch data. And these should be cited so that conclusions drawn from the data are viewed in the proper perspective. First, the catches of skipjack tuna by this gear are extremely small. In the years 1962-66, for example, the catch of skipjack tuna in the Japanese commercial tuna longline fishery averaged metric tons per year, as compared with an average of metric tons caught by the pole-and-line fishery. The smallness of the catch reflects the inefficiency of the gear for taking this species, but, because of the wide areal coverage by this gear, these data should be useful for determining areas of high or low relative abundance. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.