[All-postdocs] Bioseminar - Tiago Cidade

[Ana Velez]

Woods Hole Oceanographic Institution
Biology Department Seminar

Thursday, January 8, 2026 - 12:00 pm
Redfield Auditorium

Tiago Cidade
Fullbright Fellow, WHOI

Adaptive Fleets in a Dynamic Ocean: How Shifting Longline Strategies and Ocean Dynamics Drive Shark Vulnerability
Industrial pelagic longline fisheries are generally managed under the assumption of operational stability. However, fleets can rapidly adapt their spatial distribution and fishing strategies, leading to ecological consequences that remain insufficiently quantified. By integrating high-resolution Automatic Identification System (AIS) tracking data with onboard observations, this study demonstrates that the Spanish industrial longline fleet has substantially reconfigured its operations throughout the Atlantic Ocean following newly implemented regulations. This reorganization is characterized by increased line soak durations, overlapping gear deployments, and targeted relocations to predictable pelagic shark aggregation zones, particularly in the South Atlantic. Despite the intensification of fishing effort, these adaptations did not increase predator-gear encounter rates or meaningfully improve catch metrics relative to effort. Instead, they significantly elevate exposure and at-vessel mortality for incidentally captured shortfin mako sharks (Isurus oxyrinchus), which face two converging threats: reduced ability to evade capture within aggregation hotspots and restricted access to refugial habitats essential for post-encounter recovery. Interpreting these patterns requires acknowledging that pelagic shark movements are structured by physical oceanographic processes rather than occurring randomly. Mesoscale oceanographic features redistribute heat, nutrients, and prey, thereby creating dynamic habitats that influence predator movement, foraging behavior, and thermal access. Satellite telemetry data indicate that sharks frequently associate with eddy cores and boundaries, exhibiting looping trajectories, directional changes, and prolonged residency within these evolving features. Understanding shark responses to such oceanographic structures is critical for interpreting spatial patterns of vulnerability and for anticipating areas where ecological risk may intensify in the open ocean.

Biology Seminar Web Page<https://www.whoi.edu/what-we-do/understand/departments-centers-labs/bio/bio-highlights-events/>

For questions, contact:

Ana Maria Velez
Biology Pre-Award Administrative Associate
Ph: 508-289-2334
[signature_1005462319]

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