Speaker I: Dr. Steven Cadrin

Title: New Frontiers in Fisheries Science

Abstract: Fishery science was traditionally focused on single species population dynamics to achieve optimum yield. However, the effects of climate change on fishery productivity and efforts to mitigate the effects of climate change have accelerated the need for socio-ecological approaches. Traditional stock assessments that assume stationary productivity are no longer accurate for many species impacted by climate change. In response, recent stock assessments of New England groundfish identified ecosystem influences, like bottom temperature, Mid-Atlantic Cold Pool indices, and the Gulf Stream index, which have significant effects on recruitment, natural mortality, growth, and catchability of fisheries and surveys. These environmental effects are being used to standardize fishery and survey catch rates and as covariates in population dynamics models. Accounting for environmental drivers in stock assessment and fishery management can adapt to changing conditions, but fishery managers cannot completely mitigate the effects of climate change.

Reducing emissions through the development of renewable energy may be the most effective strategy to mitigating the effects of climate change. However, offshore wind farms also effect fisheries through ecosystem changes and direct impacts on fishing. In response, fisheries research is pivoting to multi-scale socio-ecological studies to understand potential impacts on the ecosystem and fisheries. Pre-construction baseline surveys are ongoing and transitioning to construction or operation phase monitoring to detect impacts on all major ecosystem components, from plankton to whales. Fishery monitoring data designed to support stock assessment and fishery management are now being used to estimate economic impacts. These recent applications demonstrate how climate change and offshore wind farms have accelerated the development of marine spatial planning, ecological research at multiple scales, operational socioeconomic analyses, and ecosystem approaches to stock assessment and fishery management.


Speaker II: Ágata Piffer Braga

Title: River Plume Front Evolution: Structure and Dynamics Observed from 32 Consecutive Frontal Transects Obtained by a T-REMUS

Abstract: The sharp fronts that bound river plumes are knowingly a highly dynamic region. However, plume fronts are challenging to sample repeatedly and thoroughly, due to their propagation speed, and relatively small spatial and temporal scales. Much of the existing literature examines fronts at a specific period of the plume evolution, usually within the near field, and provides only partial insight into their structure. These studies often focus on vertical profiles obtained through limited casts or describing the velocity structure while the front passes over a mooring. In the latter, the density structure is constrained to a few discrete points at the locations of the CTD sensors along the mooring line.

To achieve a more holistic understanding of the frontal zone, we developed a unique sampling plan with an autonomous underwater vehicle (T-REMUS) assisted by a drone, drifters, and shipboard sensors. The method allowed us to accomplish more than 32 frontal crossings throughout the Merrimack River Plume propagation, from the discharge until its arrest. Our goal was to compare the data collected in these crossings of the front and observe how the dynamics and main characteristics changed over time, while also evaluating their interplay and mutual influences. Additionally, aerial drone footage supplemented the T-REMUS data, capturing visual changes such as shifts in the foam line, variations in surface color, and surface roughness.

Our results identify three distinct stages in frontal zone evolution: Advective, Transition, and Arrested. These stages involve changes in the stratification, intensity, shape, and depth of the frontal revolving cell and downwelling, aligning with shifts in momentum equation dominant terms. Initially, acceleration and pressure gradient terms prevail, gradually ceding influence to the growing Coriolis effect, working together with acceleration to counterbalance pressure gradients. This deceleration process likely contributes to the release of frontal energy via internal waves and a shift in the turbulent processes of the front.


Speaker III: Robert DiGiovanni

Title: Whales, seals, and sea turtles.  What is going on in Southern New England and New York Bight?

Abstract: The Atlantic Marine Conservation Society (AMSEAS) was formed in 2016 with the mission of promoting marine conservation through action.  AMSEAS is a 501 © 3 not for profit organization authorized by National Oceanographic and Atmospheric Administration (NOAA Fisheries) and the United States Fish and Wildlife Service (USFWS) to respond to stranded marine mammals and sea turtles, as part of the marine mammal health and stranding response program and sea turtle salvage network.  Between 2017 and 2023 AMSEAS has responded to over 1300 whales, dolphins, seals and sea turtles.  Of these animals, over 100 were large whale stranding in the New York Bight.  AMSEAS conducts outreach and education programs with the public and municipalities discussing the animals that can be encountered and the threats they face.  Research programs include surveys for marine mammals and sea turtles (aerial, shipboard, and land) to assess seasonal occurrences.  Research programs for AMSEAS build on thirty years of seal research in the northwest Atlantic.  This research includes the seal ecology and health assessment program. This program is a partnership between AMSEAS, Marine Mammals of Maine (MMoME), Northeast Fisheries Science Center (NOAA Fisheries, NEFSC), Naval Undersea Warfare Center (RI), and Tufts University, Runstadler Lab) which collaborate to collect data on seal ecology, samples collected include biological, life history and satellite tagging data from wild caught animals.  AMSEAS also prepares for critical events through the operation of the Specially Trained Animal Response Team (START) and the operations of the sea turtle critical care facility built during Covid to assist our network partners with cold stunned sea turtles. This talk will review current stranding occurrences for large whales and present data on harbor and gray seal movement in Southern New England and the New York Bight.

  1. Atlantic Marine Conservation Society, 381 Suite 19, Old Riverhead Road, New York 11978
  2. UMASS Boston, 100 Morrissey Blvd, Boston, MA 02125


Speaker IV: Siddhant Kerhalkar

Title: Physics of Hurricane wake evolution: A case study in the Arabian Sea

Abstract: Hurricanes (also called cyclones) traversing oceans often leave behind cold, salty and chlorophyll-rich water wakes due to increased vertical mixing from high wind stress. However, comprehensive in-situ observations of the recovery of these wakes are rare. In this talk, we describe a coordinated ship survey in the Arabian Sea onboard R/V Roger Revelle during June 2023, as a part of the joint India-USA program EKAMSAT*. The observational survey was conducted about 7 days after the passage of the slow-moving cyclone Biparjoy. A uCTD profiler with 4m vertical resolution was used to sample multiple zonal sections straddling a filament that emanated from the wake of the cyclone. Characterized by cold, salty and high chlorophyll waters, this approximately 30 km wide filament had a stronger front (with a buoyancy gradient of 2.5×10-7 s-2 ) at its eastern edge and a weaker but more dispersed front (a buoyancy gradient of 1.5×10-7 s-2 ) at its western edge. In this talk, we will further discuss the dynamics leading to this asymmetry of fronts at the edges of the filament, specifically looking at the vertical structures of temperature, salinity and velocities. While the surface recovery of the wake is often thought of in one-dimensional terms (i.e. dependent on daily heating and cooling cycles) following a cyclone, these observations underscore the role of coupling of the winds and the underlying three-dimensional ocean frontal processes in evolution of the cyclone wake, therefore further improving ocean modeling globally.

*Acknowledgements: The authors would like to acknowledge the support of the EKAMSAT (Enhancing Knowledge of the Arabian Sea Marine Environment through Science and Advanced Training) collaboration by the Office of Naval Research (USA) and the Monsoon Mission of the Ministry of Earth Sciences (India).