Department of Fisheries Oceanography

“LOOK BUT DON’T TOUCH: MINIMALLY INVASIVE TRAWL SURVEY TECHNOLOGY”

By:

Nicholas M. Calabrese

Advisor

Kevin Stokesbury (UMass Dartmouth)

Committee Members

Steven X. Cadrin (UMass Dartmouth), Pingguo He (UMass Dartmouth), Michael J.W. Stokesbury (Acadia University), and Anna Mercer (NOAA Federal)

Wednesday May 28th, 2025

1:00 PM

SMAST East 101-103

836 S. Rodney French Blvd, New Bedford

and via Zoom

Abstract:

The School for Marine Science and Technology (SMAST) video trawl survey employs cameras mounted in the open codend of a trawl to identify and numerate groundfish. This minimally invasive survey technology has been used for semi-annual surveys of Atlantic Cod (Gadus morhua) in the Western Gulf of Maine since 2020. Accurate estimates of absolute abundance from the video trawl survey required estimates of catchability, efficiency, and fish length. This project aimed to address these requirements through three experiments and evaluate sampling methodology in a fourth experiment. First, a passive integrated transponder (PIT) tag detection system was developed, tested, and installed in the codend of the net. The custom-designed PIT tag detection system achieved an efficiency of 79%, with detection rates influenced by tag orientation and group size. Then, a mark-recapture experiment to estimate the efficiency and catchability of Atlantic cod was conducted using this system. A Petersen mark-recapture model, based on 1,094 tagged fish and six recaptures, accounting for both discard mortality and reader efficiency, yielded a doorspread efficiency of 12% and a catchability coefficient of 0.0024 per hour of towing. Next, the accuracy of length measurements derived from an off-the-shelf stereoscopic camera mounted within the trawl was assessed. This camera produced inaccurate length measurements, however, these findings helped inform the design of a custom imaging system. Finally, optical data from the survey were used to evaluate the effects of sampling design, tow duration, and sampling intensity on the variance of population estimates through a novel analytical approach. Stratified random sampling produced more precise biomass estimates than simple random sampling. In addition, CPUE mean, and variance increased with shorter tow durations. A 30-minute tow duration minimized within-tow variability and yielded the most precise abundance estimates, although this analysis lacked factors such as fish size and logistical constraints. Collectively, this research advances fisheries-independent survey methodology by addressing key limitations of new approaches.

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Join Zoom Meeting

https://umassd.zoom.us/j/92695694559

Meeting ID: 926 9569 4559

Passcode: 106409

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For additional information, please contact Callie Rumbut at c.rumbut@umassd.edu

Department of Fisheries Oceanography

“Collapse, recovery and collapse of an important fishery”

Alex Hansell

Research Fishery Biologist, NEFSC

Wednesday, April 30, 2025

3:00 – 4:00 pm

SMAST E 101-102 and via Zoom

Abstract:

Georges Bank is a shallow plateau off the coast of New England that has supported productive fisheries for centuries. One of these fisheries targeted yellowtail flounder (Limanda ferruginea), which at its peak caught over 30,000 mt a year. However, over the last 100 years the stock has fluctuated, with periods of high abundance (1970s and 2000s) and low stock size (1990s and 2020s). A previous review published twenty years ago documented the collapse of the stock in the 1990s and subsequent recovery in the 2000s, hypothesizing the major reason for recovery was bilateral science and successfully coordinated management intervention. Unfortunately, by the time that review was published, the stock had started to decrease again and collapsed in the 2010s. Here, we update empirical indicators of spatial distribution and growth for Georges Bank yellowtail as well as apply a state-space stock assessment model that includes process error and environmental effects on annual recruitment. Results suggest that the stock has spatially contracted on the Bank, fish are smaller with less variation in size, and recruitment has decreased in recent years due to low stock size and increasing water temperature. These results give insight into an iconic New England groundfish stock, as well as, provide a unique opportunity to study the fluctuations of a stock through multiple periods of recovery and collapse.

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Join Zoom Meeting

https://umassd.zoom.us/j/93758230260

Meeting ID: 937 5823 0260

Passcode: 426839

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For additional information, please contact Callie Rumbut at c.rumbut@umassd.edu

Department of Estuarine and Ocean Sciences

“Advancements in fisheries conservation using technology and chemistry “

John Mohan

Fisheries Scientist

Wednesday, April 30, 2025

12:30 – 1:30 pm

SMAST E 101-102 and via Zoom

Abstract:

Effective fisheries conservation remains challenging due to overfishing and complex population structure of highly migratory species. Sharks and tunas migrate across international management regions and are captured, either accidentally as bycatch, or intentionally in commercial or recreational fisheries. Developing technology that can decrease shark bycatch and refining chemical tracer methods to elucidate population structure of fished stocks, will enhance fisheries conservation. Here, case studies will highlight the testing of shark bycatch technology and the application of natural chemical tags in migratory fish to support sustainable management and fisheries conservation.

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Join Zoom Meeting

https://umassd.zoom.us/j/97440069270

Meeting ID: 974 4006 9270

Passcode: 428029

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For additional information, please contact Callie Rumbut at c.rumbut@umassd.edu

Department of Fisheries Oceanography

“What does successful ecosystem-based management look like and how do we know when we are successful?”

Janne Haugen

Postdoc with IBSS Corp in support of NEFSC

Wednesday, April 16, 2025

3:00 – 4:00 pm

SMAST E 101-102 and via Zoom

Abstract:

Understanding what successful ecosystem-based management (EBM) looks like is essential for evaluating whether management objectives are being met. Linking performance measures to these objectives is therefore crucial for assessing progress. Although EBM holds promise for improving social, economic, and ecological outcomes, its implementation has been challenging, and its effectiveness unclear. One key difficulty lies in developing performance measures that are systematic, integrated, and adaptable to the diverse contexts and ocean-use sectors within an ecosystem – without becoming overly complex or difficult to implement. A semi-quantitative assessment framework that integrates transdisciplinary performance measures for ocean-use sectors, marine ecosystem status, management and tradeoffs, and human dimensions can help assess the effectiveness of EBM strategies. The framework measures performance across categories and synthesizes how well EBM is performing by tracking a multitude of indicators in each category. Case studies, utilization, and impacts of the framework will be discussed as well as how performance measures move management forward.

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Join Zoom Meeting

https://umassd.zoom.us/j/93758230260?pwd=OHJ5UDloQkZZaCtXcTlBNlR6Qm0rQT09

Meeting ID: 937 5823 0260

Passcode: 426839

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For additional information, please contact Callie Rumbut at c.rumbut@umassd.edu

Department of Estuarine and Ocean Sciences

“From Methane to Microplastics: Developing Next Generation In Situ Instrumentation ”

Beckett Colson

Research Engineer, Woods Hole Oceanographic Institution

Wednesday, April 16, 2025

12:30 – 1:30 pm

SMAST E 101-102 and via Zoom

Abstract:

Marine and freshwater processes have global impacts but are challenging to observe due to the range of spatial scales, environmental conditions, and temporal variability. In the Chemical Sensors Laboratory (CSL) at the Woods Hole Oceanographic Institution, we develop in situ instrumentation to reveal these processes by making continuous measurements directly in the environment. These instruments can deliver unprecedented spatiotemporal resolution. This seminar will focus on two instruments we have recently developed: (1) SAGE for measuring deep-sea methane and carbon dioxide, and (2) Scout for quantifying microplastics in waterways. SAGE uses laser spectroscopy with a membrane inlet to quantify dissolved methane and pCO₂, and a hollow-core fiber absorption cell to minimize dead volume and achieve a time response of only four minutes. SAGE has been deployed in a variety of deep-sea environments, from hydrothermal vents to cold seeps and mud volcanoes. Scout uses electrical impedance to detect, size, and count microplastics in a continuous water flow. It uses the unique electrical characteristics of microplastics to distinguish them from naturally occurring particulates. Scout has been used locally for surface water measurements, and we are developing a next generation suitable for use on autonomous and underwater platforms. With continued improvements to these instruments, we aim to unlock more avenues for scientific inquiry and collaboration.

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Join Zoom Meeting

https://umassd.zoom.us/j/97440069270?pwd=L2Z1bDZESTFCKzJYZWduYVhWenYvZz09

Meeting ID: 974 4006 9270

Passcode: 428029

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For additional information, please contact Callie Rumbut at c.rumbut@umassd.edu

DFO Doctoral Dissertation Defense by Benjamin Galuardi

Date:                 Monday, April 28, 2025

Time:                 1:00 p.m.

Topic:                Estimating Population-Level Movement Rates of Large Pelagic Species from Electronic Tag Information

Location:          SMAST East, Rooms 101-103

Zoom Link:     https://umassd.zoom.us/j/93461632396

Meeting ID: 934 6163 2396

Passcode: 351775

Abstract:

Spatial structure and movement have important implications for stock assessment of highly migratory species and management of fisheries that target them. Telemetry data from electronic tags (E-tags) are valuable for determining habitat utilization and behavior and offer a unique path to providing fishery-independent information on movement rates. The bridge between individual E-tag deployments and population level inference can be summarized through Markovian movement matrices, stratified in space and time (e.g., seasons). To properly apply E-tag information to populations, a thorough understanding of the limitations of the technologies and the methods by which information is derived is necessary. Chapter 1 provides a review of E-tag types and geolocation techniques for estimated location and location error. A practical integration of geolocation models and population level inference is presented in Chapter 2 as a package for the R statistical software, SatTagSim. The methods draw from an advection-diffusion framework to produce simulations based on E-tag geolocation estimates and error structures. The products and methods in Chapter 2 are applied to a large E-tag dataset for Atlantic bluefin tuna (Thunnus thynnus) in Chapter 3. Tagging data from both the eastern and western Atlantic are used to generate seasonal movement matrices. These matrices are designed to be used in a variety of spatially explicit operational and stock assessment models and management strategy evaluations. Results suggest that estimates of movement rates were more reliable for simpler movement patterns (e.g., movement among fewer areas). Deriving movement estimates from E-tag data can benefit spatially explicit stock assessments and operating models for simulation testing by providing movement estimates that are independent of fishing patterns and can be beneficial in the estimation process of spatially explicit stock assessments and management strategy evaluations. This dissertation provides tools, readily available results for future assessments, and general guidelines on the trade-off between data availability and spatial inference.

ADVISOR(S):                                Dr. Steven X. Cadrin, UMass Dartmouth

                                           (scadrin@umassd.edu )

COMMITTEE MEMBERS:          Geoffrey Cowles, UMass Dartmouth

                                                          Gavin Fay, UMass Dartmouth
Molly Lutcavage, UMass Boston

                                                          Timothy Miller (NEFSC)

NOTE:                All SMAST Students are ENCOURAGED to attend.

The Department of Fisheries Oceanography is hosting Tasha O’Hara, Research Biologist at the Coonamessett Farm Foundation, for a seminar on “Addressing dynamic environmental challenges through cooperation and innovation”. This seminar will take place April 9th from 3-4 in SMAST East 101-103, but a Zoom option is available as well! 

Abstract:

Benthic surveying is crucial for understanding marine ecosystems and developing sustainable resource management strategies. While traditional sampling methods provide valuable biological data, they often face challenges like gear escapement and overfilling. To overcome these limitations and address emerging environmental concerns, innovative, non-extractive surveying tools are increasingly necessary. The HabCam v3 Habitat Mapping Camera system integrates imaging and environmental sensor data to capture real-time information, enabling marine assessments without disturbing fragile ecosystems. This non-invasive technology plays a key role in cooperative research efforts, including Atlantic sea scallop (Placopecten magellanicus) stock assessments and benthic ecosystem surveys in offshore wind sites across New England waters. By leveraging advanced technologies on commercial platforms, researchers, industry members, and fishing communities can strengthen collaboration and build trust in shared scientific endeavors. This talk will highlight HabCam’s optical work conducted by CFF during annual stock assessments and provide an overview of ongoing offshore wind cooperative research and its benefits.

The Department of Estuarine and Ocean Science is hosting Trish Atwood, Associate Professor at Utah State University & Leader of the Aquatic Ecology and Global Change Lab, for a VIRTUAL seminar on April 9th! She will be speaking about her work on“Managing and Protecting Marine Carbon: A New Challenge for Marine Conservation”. This seminar will be held on Zoom from 12:30-1:30, but streaming will be available in SMAST East 101-103.

Abstract:

The ocean is a critical reservoir of carbon, storing vast amounts both in marine life and in seabed sediments. However, human activities—particularly certain types of fishing—pose significant threats to this carbon stock. This talk explores how fisheries, especially those involving bottom trawling and large-scale biomass extraction, contribute to the loss of marine carbon. Bottom trawling disturbs carbon-rich sediments, potentially releasing stored carbon into the water column and atmosphere. At the same time, the removal of fish biomass represents a direct extraction of organic carbon that would otherwise remain part of the marine carbon cycle. By examining the mechanisms through which fisheries impact carbon storage, this presentation highlights the urgent need to integrate carbon conservation into marine management strategies. Protecting seafloor habitats and reducing high-impact fishing practices could play a pivotal role in climate mitigation efforts, offering a powerful, nature-based solution for maintaining ocean health and planetary stability.

Department of Fisheries Oceanography

“Environmental Effects on Population Dynamics of New England Yellowtail Flounder”

By: Jessica Kittel

Advisor: Steven X. Cadrin

Committee Members: Kevin Stokesbury (UMass Dartmouth), Gavin Fay (UMass Dartmouth), Lisa Kerr (U Maine), Alex Hansell (NEFSC)

Monday April 7th, 2025

2:00 PM

SMAST East 101-103

836 S. Rodney French Blvd, New Bedford

and via Zoom

Abstract:

Yellowtail flounder, Limanda ferruginea (a.k.a., Pleuronectes ferruginea, Myzopsetta ferruginea), inhabit the continental shelf of the northwest Atlantic and historically supported target fisheries off New England. However, the Georges Bank and Southern New England/ Mid-Atlantic stocks have declined in recent decades and have not recovered despite severely restricted fisheries, suggesting that productivity may be negatively affected by climate change. Ocean waters off New England are warming four times faster than the global average, and decreased yellowtail flounder productivity has been associated with ocean warming in the region. US stock assessments of yellowtail flounder have exhibited retrospective patterns, in which contemporary estimates of abundance decrease when a new year of data is added, presenting a major source of uncertainty for determining stock status and informing rebuilding plans. Retrospective patterns may result from model assumptions that do not account for environmental effects on population or fishery dynamics. In the face of climate change, there is increasing exploration of climate impacts on stock dynamics in the context of stock assessments. However, incorrectly integrating climate information can contribute to model misspecification. Thus, it is important to identify significant relationships and understand mechanisms before including them in assessments. Process error refers to the variability in population dynamics due to natural fluctuations (such as environmental effects) not captured by the model. State space models explicitly model this uncertainty, potentially improving the accuracy of assessments and supporting more adaptive, sustainable fisheries management. I led a review of the available information on environmental drivers that may be impacting US stocks of yellowtail flounder from literature and harvesters’ ecological knowledge, tested relationships between environmental indices and components of productivity (i.e., recruitment, growth, maturity, survival), and helped developed stock assessment models that account for environmental effects. Chapter One reviews the available information on environmental drivers impacting stocks of yellowtail flounder off New England from literature and harvesters’ ecological knowledge. Results suggest that several aspects of yellowtail flounder population dynamics have been sensitive to the environment, including geographic distribution, recruitment, and potentially other components of production such as natural mortality and growth. Chapter Two tested relationships between environmental indices and components of population dynamics. Generalized Additive Models (GAMs) were applied to explore relationships between the identified environmental variables and stock dynamics to determine what data should be explored in the yellowtail flounder stock assessment models. Several potential climate impacts were identified. Recruitment of yellowtail flounder off southern New England was correlated to the Mid-Atlantic Bight Cold Pool. Recruitment of yellowtail flounder on Georges Bank was correlated with bottom temperature and the Atlantic Multidecadal Oscillation. Chapter Three developed an assessment model for the Georges Bank yellowtail flounder stock that accounts for environmental effects. Results show that incorporating environmental covariates into the stock assessment improves model diagnostics and reduces uncertainty in short-term projections. This research has implications for improving assessment and management of New England yellowtail flounder fisheries and serves as a model for how appropriate ecosystem drivers can be identified for use in integrated state-space stock assessments for other assessments.