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Relative Abundance Of Pelagic Sharks In The Western North Atlantic Ocean, Including The Gulf Of Mexico And Caribbean Sea, Enric Cortes, Craig A. Brown, Lawrence R. Beerkircher
Relative Abundance Of Pelagic Sharks In The Western North Atlantic Ocean, Including The Gulf Of Mexico And Caribbean Sea, Enric Cortes, Craig A. Brown, Lawrence R. Beerkircher
Gulf and Caribbean Research
Little information exists on the status of pelagic shark populations in the Atlantic Ocean, especially in the Gulf of Mexico and Caribbean Sea. We derived indices of relative abundance for pelagic sharks based on mandatory logbooks and observer reports from a scientific observer program of the United States (US) pelagic longline fleet. Time series data from the pelagic longline logbook program (1986-2005) and the pelagic longline observer program (1992-2005) were standardized with Generalized Linear Model (GLM) procedures. Declines in relative abundance for the 6 pelagic shark species or genera examined in the logbook data analysis ranged from 43% for mako …
Nocturnal Depth Distribution Of Western North Atlantic Swordfish (Xiphias Gladius, Linnaeus, 1758) In Relation To Lunar Illumination, Joshua K. Loefer, George R. Sedberry, John C. Mcgovern
Nocturnal Depth Distribution Of Western North Atlantic Swordfish (Xiphias Gladius, Linnaeus, 1758) In Relation To Lunar Illumination, Joshua K. Loefer, George R. Sedberry, John C. Mcgovern
Gulf and Caribbean Research
Swordfish are known to undergo large diel vertical movements from surface waters at night to > 300 m depth during the day. Evidence presented over the past several deeades suggests the lunar cycle affects these vertical migrations. This study collected data concurrently from 7 swordfish throughout 3 consecutive lunar cycles using pop-up satellite archival tags. All individuals demonstrated an inverse relationship between recorded nocturnal depths and lunar illumination.