Massachusetts Maritime Academy

Acoustic telemetry is a common methodology in the study of animal movement, behaviour, and physiology in aquatic environments. In the marine environment, receiver performance is limited by environmental conditions and habitat (which modulate receiver detection range) and the number of tagged animals in the system (with signal collisions reducing the receiver’s ability to decode unique transmitter IDs). The Innovasea NexTrak receiver was developed to address the key challenges of detection range, number of transmissions successfully decoded, and quality of detection data. To assess how NexTrak receivers perform relative to the commonly used VR2AR receiver, we co-deployed NexTrak and VR2AR receivers on six moorings within a larger acoustic array deployed to study white shark movement ecology in Mahone Bay, Nova Scotia, Canada. We compared receiver performance in terms of (i) number of animals detected, (ii) number of transmissions received, (iii) structure and duration of detection events, and (iv) the effects of environmental noise on detection rates. Results showed 27.7 ± 14.4% more white sharks and 86.0 ± 20.9% more detections for NexTrak relative to VR2AR. At the detection-event level, NexTrak recorded more detections (3.9 ± 3.6, range: 0–19) than VR2AR (2.2 ± 3.0, range: 0–11). Detection events were also longer for NexTrak (471 ± 321 s, range: 0–1549 s) than for VR2AR (324 ± 241 s, range: 0–893 s), equating to a 45% higher detection-event duration as a proxy for increased detection range. While noise was a significant predictor of hourly detections, with each mV increase associated with a ~ 0.4% reduction in detections, there was no discernable difference between NexTrak and VR2AR in their performance relative to noise in our relatively quiet study system. Overall, it is evident that the NexTrak receiver has the potential to improve acoustic telemetry capabilities though enhanced detection efficiency and data quality relative to VR2AR. Improvements in detection range and decoding efficiency have implications for research costs, array design decisions, and the accuracy and precision of continuous movement tracks in fine-scale positioning arrays.

Abstract River herring (alewife, Alosa pseudoharengus and blueback herring, A . aestivalis ) can act as vectors of nutrient transfer between marine and freshwater environments. Adult river herring can transfer marine-derived nutrients to freshwater ecosystems during spawning migrations through excretions and direct consumption of adults, eggs, and early phase juveniles by freshwater scavengers and predators. Adults and juveniles can transfer nutrients derived during freshwater residency back to the marine environment following emigration and the same excretion and consumption mechanisms. Potential nutrient transfers were assessed by applying carbon, nitrogen, and sulfur stable isotope analyses to a collection of juvenile and adult alewives, baseline food web components, and freshwater fish predators in three ponds in southeastern Massachusetts USA. Out-migrating adult alewife tissue stable isotope values were lower for both carbon and sulfur but higher for nitrogen than in-migrating conspecifics reflecting incorporation of freshwater-derived nutrients. Most juvenile alewife stable isotope values were at steady state with freshwater food webs at the time of sampling reflecting additional export of freshwater-derived nutrients with their eventual emigration to the marine environment. Stable isotope-based detection of marine-derived nutrients in freshwater predators was limited to catadromous elvers ( Anguilla rostrata ), anadromous white perch ( Morone americana ), and semi-anadromous yellow perch ( Perca flavescens ) with no marine-derived nutrients detected in resident freshwater fish predators. However, juvenile alewives were observed in stomachs of smallmouth ( Micropterus dolomieu ) and largemouth bass ( M . nigricans ). Results further inform current alewife ecosystem-level interactions with the marine and freshwater environments that they occupy during different life history phases for the many coastal watersheds in New England.

Abstract Juvenile Kemp’s ridley (Lepidochelys kempii), loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles regularly strand following seasonal cold-stunning events in southern New England, but much of their pre-stranding ecology is poorly understood. To determine general trends in foraging preferences, habitat usage, and trophic position we used a combination of bulk (BSIA) and compound-specific (CSIA) stable isotope analyses. Carbon (δ13C) and nitrogen (δ15N) BSIA was performed on whole blood (n = 240) and muscle (n = 340) samples collected from stranded individuals of all three species. Sulfur (δ34S) BSIA (whole blood, n = 24; muscle n = 32) and δ15N CSIA (whole blood, n = 7; muscle n = 25) were applied to a subset of samples to further infer habitat use and trophic information. Stable isotopic niche overlap and muscle isotope-based trophic position (TP) estimates were similar for the three species, with green (TPBSIA=2.6, TPCSIA=2.9) and loggerheads (TPBSIA =3.1, TPCSIA=3.3) having the lowest overlap and greatest TP separation. Kemp’s ridley had intermediate estimated TP (TPBSIA 2.8, TPCSIA 3.1) and a high degree of overlap with the two other species. Turtle straight carapace length (SCL) was the main predictor of intraspecific stable isotope variation, and δ15N increased with SCL for all species and both tissue types. These patterns are consistent with ontogenetic TP increases as well as transition from oceanic to nearshore isoscapes. Higher intraspecific variation in BSIA-based TP estimates relative to CSIA-based estimates as well as variable inter-tissue stable isotope offsets provide evidence of individual variability in residency in nearshore waters prior to stranding.

The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) in 2024, gives us at least 7 years of data to analyze accounting for technology samples in marine and ships’ ballast water monitoring and forecasting. Marine technology played a crucial role in closing the gap between the adoption of the Convention and its coming into force, a 13-year gap that involved world-wide experimentation and investment in marine technologies which had to be approved for compliance by the International Maritime Organization (IMO) as well as Port States. Compliance Monitoring Devices (CMDs) with rapid results have been generally used in providing marine environmental invasion controls and have been used by Port States to enforce compliance in ballast water management. Qualitative, regulatory and quantitative data have been synthesized in this study from select experiments to test for compliance monitoring success. Going forward, rapid result devices will remain ideal in ship and port time management, particularly with a move towards electronic ballast water record books which also serve as an important forecasting tool for compliance as such data can be pre-delivered to the electronic records of the Port State for reaction prior to ship arrival, that way major issues can be dealt with while the ship is en voyage, for pre-emptive national security measures.

Climate change is shifting animal distributions. However, the extent to which future global habitats of threatened marine megafauna will overlap existing human threats remains unresolved. Here we use global climate models and habitat suitability estimated from long-term satellite-tracking data of the world’s largest fish, the whale shark, to show that redistributions of present-day habitats are projected to increase the species’ co-occurrence with global shipping. Our model projects core habitat area losses of >50% within some national waters by 2100, with geographic shifts of over 1,000 km (∼12 km yr−1). Greater habitat suitability is predicted in current range-edge areas, increasing the co-occurrence of sharks with large ships. This future increase was ∼15,000 times greater under high emissions compared with a sustainable development scenario. Results demonstrate that climate-induced global species redistributions that increase exposure to direct sources of mortality are possible, emphasizing the need for quantitative climate-threat predictions in conservation assessments of endangered marine megafauna.

Abstract Diadromous fishes migrate between marine and fresh waters for reproduction. For anadromous species, which spawn in freshwater, improved access to freshwater spawning and nursery habitats and ability of juveniles to emigrate to the ocean may support population recovery. Despite the potentially enormous influence of early life stage survival on adult population size, managers and scientists have limited capacity to assess numbers of juvenile anadromous fishes leaving freshwater ecosystems. Such data are critical for evaluating reproductive success and habitat suitability and have been identified as a top priority in anadromous fish research and management. We developed a state‐of‐the‐art underwater video and computational system to collect videos to estimate abundances and migration timing for juvenile river herring (Alosa pseudoharengus; Alosa aestivalis). We collected continuous video in the Monument River (Bourne, Massachusetts, USA) from June to November 2017. We trained three types of neural network models to detect and count fish in video frames and evaluated model performance by comparing human counts to model outputs. Our top model assessed presence and absence (F1 = 87%) and counted fish (counting error 9.4%) with an accuracy comparable to human counters (F1 = 88%). Our system's capability to collect accurate counts of emigrating juveniles will provide critical information that could be related to the numbers of spawning adults, system‐specific productivity, and spawning and nursery habitat suitability. Both the video collection system and computational model may be transferrable to other sites and for other species where tracking juvenile emigration may inform management efforts.

Disaster researchers have long sought to classify hazard events using various characteristics. Despite varying perspectives on how hazard events differ, the most commonly used classification in disaster scholarship categorizes hazard events as either emergencies, disasters, or catastrophes, which generally are described as being distinguished based on impacts, needs, stakeholder involvement, and management approach. Although this hazard event classification is useful, disaster scholars have noted it needs further refinement and development. In an effort to address these calls from disaster scholars and create a more robust hazard event classification, the traditional classification is revisited and expanded. Specifically, this article proposes the addition of a second dimension, response duration, to the existing hazard event type classification, which to this point has largely been defined by scale of impacts, needs, stakeholder involvement, and management approach. This paper argues short and long-duration emergencies, disasters, and catastrophes are categorically different and therefore require different management approaches, and can be used to categorize and distinguish between events such as COVID-19 and Hurricane Katrina and the Levee Failure. The proposed change would have important implications for emergency management practice and policy and would encourage a re-evaluation of the kinds of hazard events considered to be part of the academic purview of emergency management.

Panelists outline three qualitative methodologies: stasis networks, interlocking surveillance, and rhetorical platform analysis. Each methodology guides researchers and practitioners to identify and resolve different types of issues with the communication design of quantitative work, such as conflicts that emerge during the interpretive labor or how to assess and act against harmful policies that impact the data digital platforms collect and use.

Technical and professional communication (TPC) has taken a more proactive approach to social justice initiatives with the reintroduction of the "turn." Based on the authors' teaching and research experience with a range of students and across diverse institutional contexts, this paper outlines four key arenas that enrich and support commitments to social justice and equity. Focusing on areas including user experience (UX) & design, crisis and risk communication, surveillance technologies, and pedagogies, policies, and assessment, this "dream course" aims to show how social justice can be embedded into TPC course design, content, activities, assignments, and assessments throughout the process of building, facilitating, and evaluating courses.