June 2025 - MARMAM - devlists.uvic.ca

New publication: Characterizing Fraser's Dolphin (Lagenodelphis hosei) in the Lesser Antilles: Distribution, Movements, and Co-Occurrence With Other Cetacean Species to Inform Conservation Strategies in the Caribbean
by Lucas Bernier 14 Jun '25

14 Jun '25

Dear community, On behalf of my coauthors and the Caribbean Cetacean Society, we are excited to share our latest publication “Characterizing Fraser's Dolphin (Lagenodelphis hosei) in the Lesser Antilles: Distribution, Movements, and Co-Occurrence With Other Cetacean Species to Inform Conservation Strategies in the Caribbean ” in the journal Marine Mammal Science. Abstract: Fraser's dolphin (*Lagenodelphis hosei*) is one of the least studied dolphin species due to its tropical, offshore distribution and low density. However, it is frequently observed in the Lesser Antilles, where we characterized its distribution and ecology using 4 years of data collected from Grenada to Anguilla. We employed species distribution models, movement analysis, and co-occurrence analysis with other species. Fraser's dolphin was the second most encountered delphinidae species, with confirmed sightings throughout the Lesser Antilles. Depth, slope, distance to canyons, and eastward current velocity best explained the observed distribution, accounting for 22% of the variance. The Caribbean side of the Lesser Antilles represented a continuum of suitable habitat, with resightings of 10 individuals indicating inter-island connectivity from the Grenadines to Guadeloupe (415 km). Notably, Fraser's dolphin exhibited the highest co-occurrence rate (83%) and stood out statistically from other species in co-occurrence frequency and strength, underscoring the ecological significance of interspecies interactions. Overall, Fraser's dolphins in the Lesser Antilles likely represent a single population restricted to the arc, with negligible spatial fragmentation. Our results highlight the regional connectivity and the need for cooperation and harmonization of regulations in the Lesser Antilles to ensure effective conservation of the cetacean community. open access is available at: https://onlinelibrary.wiley.com/doi/10.1111/mms.70039 For further request feel free to reach out:lucas.bernier@ccs-ngo.com Best wishes, Lucas Bernier

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New publication: Captive Male and Female West Indian Manatees Display Variable Vocal and Behavioral Responses to Playbacks of Conspecifics
by Beth Brady 13 Jun '25

13 Jun '25

Hello MARMAM community, My co-authors and I are pleased to present our new publication in early view online in Marine Mammal Science. Captive Male and Female West Indian Manatees Display Variable Vocal and Behavioral Responses to Playbacks of Conspecifics Beth A. Brady, Eric A. Ramos, Jake A. Lasala, Zoe Nadine R. Ferrell, Nicholas A. Kaney, Emerson Martinez, Maria Renee Areolla Illescas, Joe Arena ABSTRACT Manatees exhibit diverse vocalizations in various behavioral contexts, but the exact role of these sounds, particularly in terms of sex- based distinctions, remains elusive. This study sought to discern the behavioral and vocal responses of two subspecies of captive West Indian manatees (Trichechus manatus) to different call types (squeaks and squeals) to determine whether differences are related to the sex of the signaler. In Mexico, four female Antillean manatees (Trichechus manatus manatus) were subjected to playbacks, while in Florida, two male Florida manatees (Trichechus manatus latirostris) were used for a parallel experiment. Vocal responses were captured using two hydrophones, with an underwater speaker system facilitating the playback. Video footage was collected to observe behavioral changes in response to playback. Results indicated that neither male nor female manatees increased the number of calls, changed call type, or altered acoustic parameters regardless of call type or whether the sound played was male or female. Likewise, neither males nor females significantly altered their behavior or movement towards the speaker in response to male or female calls, or call type. However, individual Antillean manatees exhibited variation in their behavioral responses to playback of conspecific vocalizations. The results suggest that manatees may not distinguish between the sex of callers. Please feel free to email Beth Brady at biobbrady(a)gmail.com for a copy of our publication. Thank you, Beth Brady, PhD Director of Science and Conservation Save the Manatee Club

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New Publication Announcement
by Ellen White 13 Jun '25

13 Jun '25

Dear MARMAM colleagues, We are pleased to announce that the following paper is now available online: Ellen L. White, Paul R. White, Jonathan M. Bull, Denise Risch, Susanna Quer, Suzanne Beck. Evaluating the performance of automated detection systems for long-term monitoring of delphinids in diverse marine soundscapes. PLOS One 20(6): https://doi.org/10.1371/journal.pone.0323768 Abstract: There is an increasing reliance on passive acoustic monitoring (PAM) as a cost-effective method for monitoring cetaceans, necessitating robust and efficient automated tools for extracting species presence. This work compares two methods, one based on the ‘off-line’ analysis of raw PAM data, using Convolutional Neural Networks (CNNs), and the second based on in-situ detections, implemented within the C-POD. The C-POD is a rapid, low-cost choice for monitoring of odontocetes, while CNNs, requiring large efforts to train, are gaining traction within bioacoustics as they offer performance benefits above standard detection and classification tools. This work represents the first empirical comparison of a C-POD with a system using a CNN on recorded raw acoustic data for monitoring delphinids. The comparison is based on 3000 hours of PAM data, collected off the west coast of Scotland, using a collocated C-POD and SoundTrap acoustic recorder. Results show that the system using a CNN achieves an overall accuracy of 0.82, and an effectiveness (F1-Score) of 0.78 as a click detector, whilst the C-POD achieves scores of 0.71 and 0.62, respectively. The method employing a CNN provides a lower missed detection rate, with the C-POD failing to detect > 90% delphinid positive hours at one focal site. However, the C-POD offered a lower false-positive rate across all analysis sites. This work highlights the importance of incorporating the right automated tools for long-term species monitoring, as the C-POD offers high precision rates for click detections, while the CNN based system provides a robust approach to identifying seasonal and diurnal trends in long-term dolphin occurrence. Keywords: Acoustics, Bioacoustics, Marine Monitoring, Machine Learning, CNNs, Delphinids. A PDF copy of the paper can be downloaded from: https://doi.org/10.1371/journal.pone.0323768 Please do not hesitate to contact me for any questions regarding our work. Best Regards, Ellen White --

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Postdoc Position in Southern Ocean marine predator tracking
by Mia Wege 12 Jun '25

12 Jun '25

*Postdoctoral Researcher in Marine Predator Ecology and Habitat Modelling* The University of Canterbury’s Gateway Antarctica, School of Earth and Environment invites applications for a Postdoctoral Researcher to analyse satellite tracking and diving data from multiple marine predator species in the Ross Sea, Antarctica. This 9-month fixed-term position (with potential for extension) will focus on modelling animal movement and habitat use to support conservation efforts in the Ross Sea Marine Protected Area. *Research Scope* The successful candidate will: - Process and analyse large, complex datasets from satellite-tagged marine predators (e.g., seals, penguins, or whales). - Develop movement ecology models and habitat suitability frameworks using R or equivalent programming tools. - Collaborate with interdisciplinary teams to link predator behaviour to environmental drivers. - Publish findings in high-impact journals and contribute to Antarctic conservation policy discussions. *Candidate Requirements* - A PhD in ecology, marine biology, biogeography, or a related quantitative field. - Proven expertise in R/Python for handling spatial/telemetry data. - Experience with animal movement analysis. - Strong publication record and ability to work independently in a remote collaboration environment. - Familiarity with Antarctic ecosystems or marine megafauna is advantageous but not essential. *Location and Benefits* - Based at the University of Canterbury in Christchurch, New Zealand: a gateway city to Antarctic research. *Application Instructions* Submit a *cover letter*, *CV*, and *contact details for three referees* to Dr Mia Wege (mia.wege(a)canterbury.ac.nz) Review begins immediately and continues until the position is filled. *The University of Canterbury is committed to fostering a diverse academic community and encourages applications from underrepresented groups in STEM.*

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New Publication: Seasonal changes in physical oceanography modulate cetacean predator-prey dynamics in the San Diego Trough
by Shelby Bloom 12 Jun '25

12 Jun '25

Dear colleagues, On behalf of my co-authors and myself, we are excited to share our new publication in MEPS titled "Seasonal changes in physical oceanography modulate cetacean predator-prey dynamics in the San Diego Trough" Shelby G. Bloom, Michaela N. Alksne, Ally Rice, Matthias Lankhorst, Ana Širović, Joseph D. Warren, Simone Baumann-Pickering Abstract: In marine ecosystems, cetaceans are large mobile predators that depend on maximizing foraging efficiency. Their presence within a habitat can therefore be strongly related to the modulation of local prey by oceanographic conditions. Understanding how cetaceans are impacted by prey responses to the physical environment is challenging due to the difficulty of collecting presence data of cetaceans and their prey over long, comparable time periods. We used passive and active acoustic recordings collected from moorings within the San Diego Trough, along with physical oceanographic sampling (i.e. *in situ*, satellite-derived, and ocean general circulation model measurements), to elucidate relationships between cetaceans, their prey, and the physical environment. Our results show that the predator–prey dynamics of some cetaceans within the San Diego Trough are influenced by seasonal changes in the physical oceanographic conditions and processes that shape their prey resources. Specifically, common dolphin *Delphinus delphis* foraging activity increased during conditions associated with increased presence of diel vertically migrating fish prey. Blue whale *Balaenoptera musculus* foraging-associated acoustic activity increased during periods with increased presence of mid-water crustacean zooplankton and was replaced with breeding-associated acoustic activity during conditions associated with the waning of mid-water crustacean zooplankton. Fin whale *B. physalus* foraging-associated calling activity was more complex to model, most likely because these animals have a generalist diet and occupy this area year-round. Our results highlight environmental conditions and features relevant to cetaceans inhabiting this region and may aid in developing better spatially explicit management actions. The full article is available as open access at the following link: https://www.int-res.com/abstracts/meps/v762/meps14864 Cheers, Shelby Bloom, MS Research Data Analyst Marine Bioacoustics Research Collaborative <https://mbarc.ucsd.edu/ > Scripps Institution of Oceanography

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Invitation to contribute to survey on noise impacts and regulation for marine mammals
by michael.daehne＠gmx.com 12 Jun '25

12 Jun '25

Dear Marmam list members and experts on noise impacts on marine mammals, My student Alexander Henning has created a survey on noise impacts on marine mammals during his Bachelors thesis in Biosciences at the University of Rostock (Germany). It focusses on international and national protection of marine mammals in the context of noise-intensive offshore projects. I would like to invite you to participate in this online survey to collect and compare international approaches to noise regulation and mitigation. National approaches to managing underwater noise and protecting marine mammals are of particular interest. We particularly invite marmam participants from all countries but would specifically encourage those from countries that do not regularly participate in international steering groups considering underwater noise and would therefore be underrepresented. The survey takes approximately 15-25 minutes to complete and can be accessed here: https://docs.google.com/forms/d/e/1FAIpQLSeD6IS8unzPo56rsGUo1HBCZfzqSLXWHjT XvtJmhdmxEO19sw/viewform?usp=header Your participation would be greatly appreciated. All responses are confidential and used solely for academic purposes. Your insights would contribute a better understanding of international strategies for marine mammal protection. If you have any questions or need further information, please feel free to contact me. Thank you very much in advance for your time and support. Sincerely, Alexander Henning and Michael Dähne University of Rostock, Department of Biosciences Please respond to alexander.henning(a)uni-rostock.de <mailto:alexander.henning@uni-rostock.de> for any further questions

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New paper on the relationships between body size, nutritional state, endocrine state and calving probability in gray whales
by Enrico Pirotta 12 Jun '25

12 Jun '25

Dear MARMAM colleagues, We are pleased to announce that the following paper is now available online: Enrico Pirotta, Leslie New, Alejandro Fernandez Ajó, K. C. Bierlich, Clara N. Bird, C. Loren Buck, Lisa Hildebrand, Kathleen E. Hunt, John Calambokidis, and Leigh G. Torres. Body size, nutritional state and endocrine state are associated with calving probability in a long-lived marine species. Journal of Animal Ecology. Abstract: 1 - Life-history performance of individuals in wildlife populations emerges from the interplay between the multiple processes that constitute an animal's health. Monitoring and modelling indicators of health can thus provide a way to assess and forecast the status of a population before its abundance changes. 2 - In this study, we develop a Bayesian state–space model that links multiple health indicators (representing energy, endocrine and morphometric status) and resulting female calving probability, using an 8-year dataset of repeated sightings, morphological measurements, faecal sampling and offspring observations of gray whales (*Eschrichtius robustus*) belonging to the Pacific Coast Feeding Group. 3 - Model results indicate that calving probability emerges from the combined effect of a female's structural body size and available energy reserves, while also showing a weak negative correlation with glucocorticoid levels prior to pregnancy. Assessment of population age structure suggests that the number of individuals in younger age classes is smaller than expected for a growing or a stable population, which, together with decreasing body size, could indicate an impending decline in this group. Model development was made possible by the collection of high-resolution, longitudinal data on individuals, although several mechanistic assumptions were imposed by the relatively short time series (8 years), influencing the results. 4 - Our modelling approach could inform similar efforts in other long-lived species where population dynamics cannot be easily monitored. Ultimately, models of wildlife health and vital rates can support assessments of the population-level consequences of multiple stressors, a key goal for management and conservation across systems and jurisdictions. Keywords: Bayesian state–space modelling, calving probability, early warning signals, gray whales, health, Pacific Coast Feeding Group, population consequences of disturbance. A PDF copy of the paper can be downloaded from: https://doi.org/10.1111/1365-2656.70068 Please do not hesitate to contact me for any questions regarding our work. Best Regards, Enrico Pirotta

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New publication: Rates, Oxygen Stores and Calculated Aerobic Dive Limits of Foraging Gray Whales, Eschrichtius robustus (James Sumich)
by James Sumich 11 Jun '25

11 Jun '25

My co-authors and I are pleased to share our new Note just published online in Marine Mammal Science: Sumich, James L., Renee Albertson and Lani Stelle. Ventilatory Patterns, Oxygen Consumption Rates, Oxygen Stores and Calculated Aerobic Dive Limits of Foraging Gray Whales (Eschrichtius robustus). You can access it at:http://doi.org/10.1111/mms.70032 SUMMARY: The routine ventilatory behaviors of actively foraging gray whales are expected to avoid excursions into anaerobiosis by remaining within their aerobic dive limits (ADL). We estimated ADL as the quotient of an animal’s total O2 stores divided by its rate of O2 consumption, utilizing published estimates of actively foraging gray whale field metabolic rates and of lung, blood, and muscle O2 stores to calculate ADL values and compare them to observed patterns of dive durations of adult foraging gray whales. We then discuss possible reasons why typical observed extended dive times of foraging gray whales are well short of their predicted ADL.

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New publication: Quantifying vessel noise and acoustic habitat loss in marine soundscapes
by Benjamin Hendricks 10 Jun '25

10 Jun '25

Dear Marine Mammal Community, On behalf of my co-authors, I'd like to share our new study published in Marine Pollution Bulletin in which we describe a framework to quantify underwater vessel noise from all types of motorized craft in aquatic soundscapes and link these excess noise levels to the degree of acoustic habitat degradation for marine mammals. Title: "Quantifying vessel noise and acoustic habitat loss in marine soundscapes" Authors: Benjamin Hendricks, Matt K. Pine, Grace Baer, Maureen Welton, Helena K. Symonds, Tom Dakin, Hussein M. Alidina, Chris R. Picard, and Janie Wray Abstract: Quantifying underwater vessel noise in marine ecosystems is challenging, due to difficulties in accounting for small, not publicly tracked boats, creating a knowledge gap in marine management. We present a computationally efficient framework that detects all vessel noise in hydrophone recordings and quantifies associated excess noise levels as well as acoustic habitat loss, offering a cost-effective and replicable tool for assessing vessel noise effects on marine soundscapes. Applied to one year of acoustic data from five sites along the coast of British Columbia (BC), Canada, the detector achieved 96.4 % accuracy and was robust against varying levels of vessel traffic and weather conditions. Across sites, vessel noise impacts increased with proximity to urban centers. Following this trend, average annual vessel noise presence ranged between 24 % and 85 %, increasing the 500 Hz decidecade band by 1.0 dB to 6.4 dB across sites. The average year-round acoustic habitat loss for killer whales, expressed as the reduction of listening space in a 0.5–15 kHz communication band, ranged from 6.6 % to 46.9 %. Vessel noise impacts were generally higher during daylight hours and in the summer months. The results are the first comprehensive, empirical assessment of vessel presence and associated noise impacts for a regional ecosystem in BC. Open Access Link: https://www.sciencedirect.com/science/article/pii/S0025326X25006253 All data for this study were collected and made available by the BC Hydrophone Network and their partners: https://whalesound.ca/ We are currently working on publicly hosting the Python code for all algorithmic components described in the paper. If you are interested in using the code---or if you have any other comments or questions---please feel free to reach out. Best regards, Ben Hendricks, PhD | SoundSpace Analytics www.soundspaceanalytics.ca Email: benhendricks(a)soundspace-analytics.ca Phone: +1 250 532 3179

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New publication on Association Patterns of Indo-Pacific Bottlenose Dolphins in Waters off the North West Cape, Western Australia
by Guido Parra Vergara 10 Jun '25

10 Jun '25

Dear colleagues, On behalf of all co-authors, I am pleased to share our new publication in Marine Mammal Science: Edwards, C.M., Syme, J. and Parra, G.J. (2025), Association Patterns of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) in Waters off the North West Cape, Western Australia. Mar Mam Sci e70017. https://doi.org/10.1111/mms.70017 ABSTRACT This study examined association patterns, social clustering, and temporal stability of Indo-Pacific bottlenose dolphins off the North West Cape (NWC), Western Australia. Over 6 years, boat-based surveys collected photo-identification data, enabling repeated sampling, sighting history construction, and associate identification. Among the 344 adult dolphins identified, 116 were sighted at least five times and used in association analyses. A strong correlation (r = 0.86 ± 0.01 SE) between true and estimated association indices, along with a high coefficient of variation (S = 1.92 ± 0.9 SE), indicates a highly differentiated society with diverse relationships among individuals. Generalized affiliation indexes, social network metrics, and lagged association rates revealed predominantly loose, short-term associations within a well-connected but non-clustered social network. These fluid association patterns are likely related to the open and transient nature of this population, where individuals move in and out of the study area. These movements provide opportunities for social interactions among different individuals, and members of different groups may fission for varying periods of time. Findings from this study provide a solid baseline for future studies looking at the sociogenetic structure of this population and the environmental and social factors driving their fluid social system. Full text available at: https://doi.org/10.1111/mms.70017 All the best, Guido ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Guido J. Parra, PhD Associate Professor | College of Science and Engineering Research leader | Cetacean Ecology, Behaviour and Evolution Lab (CEBEL) Staff: http://www.flinders.edu.au/people/guido.parra Lab: www.cebel.org.au<http://www.cebel.org.au> GoogleScholar<https://scholar.google.com.au/citations?hl=en&user=7YisEoAAAAAJ> | ResearchGate<https://www.researchgate.net/profile/Guido_Parra> | LinkedIn<https://www.linkedin.com/in/guido-j-parra-093217183/> Flinders University, GPO Box 2100 Adelaide, SA 5001 Australia Tel: +61 8 8201 3565|email: guido.parra(a)flinders.edu.au<mailto:guido.parra@flinders.edu.au> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Please consider the environment before printing this email

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