Seasonal Distributions of Larval Flatfishes (Pleuronectiformes) on the Continental Shelf Between Cape Cod, Massachusetts, and Cape Lookout, North Carolina, 1965-66
Seasonal Distributions of Larval Flatfishes (Pleuronectiformes) on the Continental Shelf Between Cape Cod, Massachusetts, and Cape Lookout, North Carolina, 1965-66

Author: W. G. Smith

Publisher:

Published: 1975

Total Pages: 636

ISBN-13:

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Larval flatfishes, representing 4 families, 17 genera, and 15 species, were identified from collections taken during a 1-yr survey designed to locate spawning grounds and trace dispersion of fish eggs and larvae on the continental shelf. Most flatfishes began spawning in the spring, a time of marked seasonal temperature change. The seasonal distribution of larvae indicated that: 1) bothids had longer spawning seasons than pleuronectids; 2) pleuronectids spawned largely in the northern half of the survey area during the spring; 3) most bothids spawned in the southern half, beginning in spring and continuing through early fall; 4) although cynoglossids spawned incidentally off North Carolina, most of their larvae were transported into the survey area from spawning grounds south of Cape Lookout; 5) the few representatives of the family Soleidae originated south of Cape Lookout; 6) spawning that began in the spring proceeded from south to north as the season progressed, but spawning that began in the fall proceeded from north to south, suggesting that the onset of spawning is triggered by spring warming and fall cooling; 7) most species spawned within a relatively narrow range of temperature; 8) salinity had no apparent influence on spawning.

Distribution, Relative Abundance, and Movement of Skipjack Tuna, Katsuwonus Pelamis, in the Pacific Ocean Based on Japanese Tuna Longline Catches, 1964-67
Distribution, Relative Abundance, and Movement of Skipjack Tuna, Katsuwonus Pelamis, in the Pacific Ocean Based on Japanese Tuna Longline Catches, 1964-67

Author: Walter M. Matsumoto

Publisher:

Published: 1975

Total Pages: 802

ISBN-13:

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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.