Patterns of Vertical Habitat Use by Atlantic Blue Marlin (Makaira nigricans) in the Gulf of Mexico
We examined data from pop-up archival transmitting (PAT) tags (n = 18) to characterize aspects of vertical habitat use by blue marlin (Makaira nigricans) from the Gulf of Mexico (GOM). Two of these tags were recovered and provided fine-scale information about diving patterns and the relationship between time at depth and temperature. Similar to previous studies, blue marlin in the GOM spent most of their time at the surface and at temperatures within 3° C of surface temperatures. Time at depth was multimodal and the magnitude of the smaller modes was dependent upon the strength and depth of the thermocline. Importantly, time at depth was a complex function of the temperature change relative to the surface, time of day, lunar phase, and water column structure. Temperature change with depth between the western and eastern GOM and the adjacent western Atlantic Ocean was also examined. The depth range (maximum depths varied between 68 and 388 m) varied widely between fish and did not appear to correspond with any particular magnitude of temperature change relative to the surface. Although these data may help to improve stock assessments that are based upon habitat standardizations of CPUE, progress will be limited until the distribution of feeding activity with depth and other aspects of blue marlin behavior in relation to capture probability are elucidated.
Kraus, R. T. and J. R. Rooker.
Patterns of Vertical Habitat Use by Atlantic Blue Marlin (Makaira nigricans) in the Gulf of Mexico.
Gulf and Caribbean Research
Retrieved from http://aquila.usm.edu/gcr/vol19/iss2/11