Virginia Institute of Marine Science
MARINE AND COASTAL FISHERIES
Bluefin Tuna Thunnus thynnus are highly sought after in commercial and recreational fisheries along the East Coast of North America. To appropriately assess and manage Atlantic Bluefin Tuna (ABT), it is necessary to understand their habitat use during multiple ontogenetic stages. We tagged 17 juvenile ABT in the northwest Atlantic Ocean with pop-up satellite archival tags (PSATs) to determine environmental factors that may affect habitat use. The PSATs were deployed off the coast of Massachusetts in August and September 2012. A generalized linear mixed model was applied to determine factors affecting the mean depth occupied by fish, and beta regression was used to understand factors affecting the proportion of time spent below the thermocline. Thermocline depth significantly affected the mean depth occupied by juvenile ABT and the proportion of time they spent below the thermocline. Time period (dawn, day, dusk, and night) also significantly affected the mean depth occupied by juvenile ABT. Additionally, the time period x lunar illumination interaction had a significant effect on the proportion of time spent below the thermocline. This study is the first to demonstrate that environmental factors such as thermocline depth, time period, and lunar illumination can significantly impact vertical habitat use by juvenile ABT and demonstrates the utility of generalized linear mixed models for investigating fish habitat use.
WESTERN NORTH-ATLANTIC; THUNNUS-THYNNUS DISTRIBUTION; SATELLITE ARCHIVAL TAGS; VERTICAL MOVEMENTS; BIGEYE TUNA; OCEANOGRAPHIC CONDITIONS; ULTRASONIC TELEMETRY; POSTRELEASE SURVIVAL; DIVING BEHAVIOR; THERMAL BIOLOGY
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This project was supported by the Guy Harvey Ocean Foundation and the National Science Foundation GK-12 Program (0840804). We thank the captains and crews of the Big Fish II, Big Fish III, For2na, Ocean Runner, Matador, Salty Dogs, Know Name, Game On, Sea Habit, Gina Marie, Oyster Catcher, McSeas, and Aries 55 for their participation in the study. We are also grateful to R. Brill for providing comments on an earlier version of this paper. This paper is Contribution 3538 of the Virginia Institute of Marine Science, College of William and Mary.
Marcek, Benjamin J.; Fabrizio, Mary C.; and Graves, John, Short-Term Habitat Use of Juvenile Atlantic Bluefin Tuna (2016). MARINE AND COASTAL FISHERIES, 8(1), 395-403.