LARVAL ECOLOGY OF ATLANTIC BLUEFIN TUNA (THUNNUS THYNNUS): NEW INSIGHTS FROM OTOLITH MICROSTRUCTURE, BIOTIC, AND ABIOTIC ANALYSES FROM THE GULF OF MEXICO AND MEDITERRANEAN SEA
Doctor of Philosophy
Tracey Sutton, Ph.D.
David Kerstetter, Ph.D.
Trika Gerard, Ph.D.
Raul Laiz-Carrion, Ph.D.
John T. Lamkin, Ph.D.
Atlantic bluefin tuna (ABT), Thunnus thynnus, spawn in the Gulf of Mexico (GoM) and the Mediterranean Sea (MED). Spawning occurs within narrow temporal and environmental parameters. Efforts to characterize growth of ABT in wild conditions revealed a wide range of growth variability during the early life stages. This series of studies examined potential biotic and abiotic influences of larval growth from seven ABT cohorts, and identified several key drivers of growth for this commercially valuable species. A detailed investigation of larval dynamics using otolith microstructure was conducted as follows. First, companion growth curves and stable isotope analysis from the same spawning season (2014) in the GoM and MED revealed distinct growth strategies. GoM larvae grew faster, had larger otoliths, and had wider increments associated with lower δ15N than the MED. Second, food limitation and feeding preferences explained the most variance of recent growth between two larval patches in the GoM. While mean growth rates were similar, one nursery habitat appeared better suited for faster preflexion growth, while the other had faster flexion to postflexion growth likely attributed to abundant of preferred prey (copepod-nauplii, cladocerans). Lastly, inter-annual growth from historical SEAMAP collections (2015-2017) in the GoM revealed similar growth rates between years and that among the mesoscale oceanographic features sampled, Common Water was highly suitable habitat for ABT growth. Fisheries-independent surveys targeting ABT provide larval abundances for assessments of adult spawning stock biomass. Ecological studies such as these, that incorporate environmental parameters, and integrate standardized abundance estimates, will improve current models utilized in ABT management.
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Estrella Malca. 2022. LARVAL ECOLOGY OF ATLANTIC BLUEFIN TUNA (THUNNUS THYNNUS): NEW INSIGHTS FROM OTOLITH MICROSTRUCTURE, BIOTIC, AND ABIOTIC ANALYSES FROM THE GULF OF MEXICO AND MEDITERRANEAN SEA. Doctoral dissertation. Nova Southeastern University. Retrieved from NSUWorks, . (110)
Available for download on Friday, December 22, 2023
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Funding for collections, analyses, and lab work was provided through a collaborative framework between multiple partners. These partners include Nova Southeastern University (NSU), the National Oceanic and Atmospheric Administration (NOAA), the Spanish Institute of Oceanography (“ECOLATUN” Project CTM2015-68473-R to R. Laiz-Carrión). This research was carried out in part under the auspices of the Cooperative Institute for Marine and Atmospheric Studies (CIMAS), a Cooperative Institute of the University of Miami and NOAA under cooperative agreement NA20OAR4320472. Partial funding was also provided by the NOAA RESTORE Science Program grant (NOAA-NOS-NCCOS-2017-2004875 to J. Lamkin and T. Gerard). Funding was also provided by the NOAA Fisheries and the Environment grant to K. Shulzitski. In addition, a NSU Ph.D. Graduate Fellowship partially funded tuition along with two scholarships from the Fish Florida Scholarship Program. Finally, the NOAA Bluefin Tuna Research Program (BTRP) to W. Golet and T. Sutton supported partial tuition and analysis of samples.