Abstract:

Regulations and a strong conservation ethic among anglers make Striped Bass among the most frequently released coastal marine fishes. Given the currently assumed 9% release mortality rate, these recreational releases account for the majority of human removals from the stock. In an attempt to reduce this mortality rate, fishery managers have recently begun requiring that anglers use circle hooks when fishing with natural baits for Striped Bass. To measure the reduction in release mortality resulting from this rule change, we conducted a two-year acoustic telemetry experiment (n = 349 fish) to compare the survival of bass caught via circle hooks and conventional J-hooks. This telemetry dataset was also used to estimate mortality rate as a function of a release “condition score”, which is a simple visual assessment of the injury and vitality of released fish. By combining these telemetry results with fishery observations of release condition from a citizen science project (n = 8,349 fish), a machine learning model was developed to predict mortality rate from a suite of biological, environmental, and fishing variables. This model was then used to generate an updated comprehensive estimate of release mortality rate by accounting for fishery-wide patterns in the suite of predictors. Although we found that circle hooks did not provide a conservation benefit for Striped Bass, our results demonstrate that release mortality for the recreational fishery is on average 4%, which is less than half of the currently assumed rate. Furthermore, a significant positive relationship between mortality rate and fish size suggests that fishery removals are more focused on older fish than previously thought.

Join on Zoom!

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

Meeting ID: 937 5823 0260

Passcode:426839

Abstract:

Spectral surface wave models predict the wave action evolution of multiple wave components. It is well understood that the group speed of the wave action of a particular wave component is modified if an Eulerian near-surface current exists. However, a typical ocean wave field also introduces a significant integrated Stokes drift or Lagrangian mass transport and its impact on the group speed of a particular wave component is not well known. In this study the wave evolution equations are derived in the presence of two wave trains and the impacts of one wave train on the phase and group speeds of the other wave train are investigated. The results are extended to estimate the impact of the entire wave spectrum on the propagation of a particular wave train. It is found that the group speed of the dominant waves can be significantly enhanced by the presence of other waves by up to 0.3–0.4 m/s or 4%–5% in strongly wind-forced conditions under tropical cyclones. This increase of the group speed is almost twice as large as the advection by a sheared current with the same profile as the Stokes drift integrated over the wave spectrum. Introducing this enhanced group speed in the wave models may make a noticeable impact on their surface wave predictions. It is also found that the increase of the phase speed of a particular wave component is much larger than the advection by a sheared current with the same profile as the integrated Stokes drift.

Join via Zoom!

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

Meeting ID: 974 4006 9270

Passcode: 428029

SMAST has partnered with the Mass Environmental Police to offer a 2-day Boating safety class on Monday, June 9^th  and Wednesday, June 11^th.  The class will be offered in SMAST East 101-102. The Class size is limited, so if you are interested, please email Mike Marino (mmarino@umassd.edu) to reserve your spot. If this date/time does not work for you but you are interested in a future training, please let him know.

This year’s IMS Symposium will be held March 26 from 9-5 at SMAST East! Register HERE!

The NEW registration deadline date Thursday March 20th at 4:00 PM. We cannot accept any after that time! Please get it done ASAP so you can be sure we have you on there :). If you are planning on presenting, also submit your abstract by March 3rd, you can find the details on the website!

Kate Masury will be joing us at SMAST East 101-103 on February 26, from 3-4! Kate Masury, executive director at Eating with the Ecosystem, will be discussing “Understanding Seafood Supply Chains: Strengthening Connections Between Fisheries, Markets, and Ecosystems”. Please join us at SMAST or on Zoom!

Abstract:

New England’s seafood supply chains are dynamic and complex, shaped by ecological shifts, regulatory frameworks, and evolving consumer demand. While the region lands an incredible diversity of seafood, much of it is exported, and local markets remain dominated by imports. How can we build more resilient, place-based seafood supply chains that better support both fisheries and communities? This talk will explore these challenges through the work of Eating with the Ecosystem and its efforts to promote a more adaptive, ecosystem-based approach to local seafood. A key focus will be the Markets to Models project, a collaboration with UMass Dartmouth’s School for Marine Science and Technology (SMAST), which is piloting an innovative marketplace model to better illustrate the connections between seafood supply chains, fisheries, and ecosystems. By mapping these connections, the project aims to identify strengths and vulnerabilities within supply chains, providing valuable insights for improving market resilience and sustainability. We’ll examine how strengthening local seafood networks can enhance economic opportunities, promote ecosystem-based management, and increase access to fresh, locally harvested seafood. By rethinking how seafood moves from boat to plate, we can create a more transparent, sustainable, and adaptive future for New England’s fisheries.

The Department of Fisheries Oceanography is hosting David Bethoney, Executive Director at the Commercial Fisheries Research Foundation, for a seminar on “From Data to Discovery: The Lobster and Jonah Crab Research Fleet”. This seminar will take place in SMAST East 101-103 on February 19, from 3-4. If you can’t make it in person, feel free to join via Zoom!

Abstract:

The CFRF Lobster and Jonah Crab Research Fleet project aims to implement a cost-effective method for collecting essential biological data on two commercially important species: the American lobster and Jonah crab. This project utilizes a fishing vessel research fleet approach, where lobster and Jonah crab fishermen gather biological and environmental data during their commercial fishing trips. This presentation on the Research Fleet will consist of two parts. The first part will focus on the development and methods used in the Research Fleet, including results that directly relate to the project’s goals. The second part will highlight extension projects developed from the Research Fleet. These extension projects encompass a variety of topics and involve additional data collection and analysis based on participant interests and feedback from scientists and managers who rely on the data.

The Department of Estuarine and Ocean Science will be hosting Katrina Velle, Assistant Professor in the Biology Department at UMass-Dartmouth on February 19! Dr. Velle will be discussing “The actin cytoskeleton drives cell migration in a model of the “brain-eating amoeba”. This seminar will take place from 12:30-1:30 in SMAST East 101-103 and on Zoom.

Abstract:

The “brain eating amoeba” Naegleria fowleri has a ~95% case fatality rate, and primarily infects children. Despite its clear importance, we have little understanding of the basic cell biological mechanisms that underlie Naegleria’s pathogenesis, which is key information for the identification of new drug targets. What is clear, however, is that actin assembly and disassembly drives many cellular processes in Naegleria. The Velle lab studies how the actin cytoskeleton promotes cell migration, cell division, and osmoregulation—three phenotypes important for establishing and spreading infection. This talk will specifically focus on cell migration. To initiate an infection, Naegleria amoebae must crawl through narrow channels in the skull to reach the brain. To study this process, we expose Naegleria gruberi (a nonpathogenic model system) to different types of confinement including microchannels. Using quantitative microscopy, we show that Naegleria amoebae seek out confinement; after contacting the entrance to a microchannel, cells continue to probe the surface until they get inside. Once cells fully enter these channels, they crawl extremely quickly (up to 100 microns/min) in one direction for millimeters. While migrating in confined environments, cells show hallmarks of “blebbing” motility, in which the plasma membrane detaches from the underlying actin cortex and blisters outward, creating an actin-free protrusion. This is in contrast to unconfined cells, which typically use actin-filled protrusions to crawl. Collectively, these data suggest that once Naegleria amoebae detect an opening to a narrow channel—similar to what they encounter during infection—cells will switch to blebbing motility to crawl quickly and persistently.