Publication Date:
2022-05-25
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy
at the
Massachusetts Institute of Technology
and the
Woods Hole Oceanographic Institution
September 2018
Description:
Highly migratory marine fishes support valuable commercial fisheries worldwide. Yet, many
target species have proven difficult to study due to long-distance migrations and regular
deep diving. Despite the dominance of oceanographic features, such as fronts and eddies,
in the open ocean, the biophysical interactions occurring at the oceanic (sub)mesoscale
(〈 100 km) remain poorly understood. This leads to a paucity of knowledge on oceanographic
associations of pelagic fishes and hinders management efforts. With ever-improving
oceanographic datasets and modeling outputs, we can leverage these tools both to derive
better estimates of animal movements and to quantify fish-environment interactions. In this
thesis, I developed analytical tools to characterize the biophysical interactions influencing
animal behavior and species’ ecology in the open ocean. A novel, observation-based likelihood
framework was combined with a Bayesian state-space model to improve geolocation
estimates for archival-tagged fishes using oceanographic profile data. Using this approach,
I constructed track estimates for a large basking shark tag dataset using a high-resolution
oceanographic model and discovered a wide range of movement strategies. I also applied this
modeling approach to track archival-tagged swordfish, which revealed affinity for thermal
front and eddy habitats throughout the North Atlantic that was further corroborated by
synthesizing these results with a fisheries-dependent conventional tag dataset. An additive
modeling approach applied to longline catch-per-unit effort data further highlighted the biophysical
interactions that characterize variability in swordfish catch. In the final chapter, I
designed a synergistic analysis of high-resolution, 3D shark movements and satellite observations
to quantify the influence of mesoscale oceanography on blue shark movements and
behavior. This work demonstrated the importance of eddies in structuring the pelagic ocean
by influencing the movements of an apex predator and governing the connectivity between
deep scattering layer communities and deep-diving, epipelagic predators. Together, these
studies demonstrate the breadth and depth of information that can be garnered through the
integration of traditional animal tagging and oceanographic research with cutting-edge analytical
approaches and high-resolution oceanographic model and remote sensing datasets,
the product of which provides a transformative view of the biophysical interactions occurring
in and governing the structure of the pelagic ocean.
Description:
Supported by the NASA
Earth and Space Science Fellowship, the MIT John S. Hennessy Fellowship, the MIT Martin
Family Society of Fellows for Sustainability Fellowship, the WHOI Ocean Venture, Grassle,
and James Stratton Fellowships and the WHOI Academic Programs Office. This research
and its dissemination was supported by funds from National Geographic, Amazon Web Services,
the Explorers Club, Rolex, Sigma Xi, the MIT Center for International Studies, WHOI
Access to the Sea and Coastal Ocean Institute Funds, MIT Graduate Student Council, MIT
Student Assistance Fund, WHOI Biology Department, American Fisheries Society, WHOI
Academic Programs Office
Keywords:
Fishes
;
Fisheries
;
Pelagic fishes
;
Eddies
;
Animal marking
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
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