November 2020 - MARMAM - devlists.uvic.ca

New publication on odontocetes trophic ecology and habitat use
by Genyffer Troina 26 Nov '20

26 Nov '20

Dear MARMAM Readers, My co-authors and I are pleased to announce the publication of our recent article in Marine Biology: Troina, G.C., Botta, S., Dehairs, F., Di Tullio, J., Elskens, M., Secchi, E.R. Skin δ13C and δ15N reveal spatial and temporal patterns of habitat and resource use by free-ranging odontocetes from the southwestern Atlantic Ocean. *Mar Biol* *167, *186 (2020). https://doi.org/10.1007/s00227-020-03805-8 ABSTRACT: Large diversity and abundance of cetacean species occur along the Brazilian outer continental shelf and slope waters. In the present study we analysed carbon (δ13C) and nitrogen (δ15N) stable isotopes in skin biopsies of ten odontocete species (Delphinidae and Physeteridae) to assess the intra- and interspecific patterns in the use of resources along the region. Our isotopic analysis allowed us to identify two potential subpopulations of *Stenella frontalis*. High core isotopic niche overlap between *S. frontalis* from the southern range of the study area and *Delphinus delphis*, especially in spring, suggested that they share similar resources and rely on spatiotemporal segregation to achieve niche differentiation and to minimize competition. Our isotopic data also pointed to high similarity among *Tursiops truncatus,* *S. frontalis *and* Globicephala melas* in the use of resources.* Steno bredanensis had the highest *δ15N and δ13C, which agrees with its occurrence in neritic waters. *S. longirostris* showed consistently low δ15N values, indicating that they feed at relatively lower trophic levels, and lack of niche overlap with most delphinid species, except *S. attenuata*. *Orcinus orca* and *G. melas* had very similar δ13C and δ15N values, that were consistent with feeding in offshore waters. δ13C and δ15N in *Physeter macrocephalus* suggested that individuals feed on similar trophic levels, but over a wide spatial range. The analyses of stable isotopes in skin biopsies helped us refine our knowledge about the intra-specific resource and habitat use, ecological niches and the trophic interactions amongst co-occurring cetaceans from the oceanic waters of the subtropical western South Atlantic. The article can be accessed via the link https://rdcu.be/cbadj Do not hesitate to contact me (genyffertroina(a)gmail.com) if you have any comments or questions. Kind regards, Genyffer Troina -- Dr. Genyffer Troina Postdoctoral Research Fellow Laboratório de Ecologia e Conservação da Megafauna Marinha (ECOMEGA) Instituto de Oceanografia – IO/Universidade Federal do Rio Grande - FURG Rio Grande/RS (CEP 96201900), CP 474, BRAZIL genyffertroina(a)gmail.com CV: http://lattes.cnpq.br/3997346742040354

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New publication on Atlantic spotted dolphin whistles
by Lis Bittencourt 26 Nov '20

26 Nov '20

Dear colleagues, On behalf of my co-authors I would like to announce our recent publication: "Whistles of Atlantic spotted dolphin from a coastal area in the southwestern Atlantic Ocean" Bittencourt, L., Barbosa,M., Santos-Neto, E.B., Bisi, T.L., Lailson-Brito,J.Jr., and Azevedo, A.F. (2020) ABSTRACT Atlantic spotted dolphins were recorded on the coastal area of Rio de Janeiro with equipment of 192 kHz sampling rate. The animals produced an average of 33 whistles/min. The repertoire was balanced among four contour categories, with the occurrence of a stereotyped whistle. Frequency parameters were measured between 1.3 and 29 kHz, which represents an increase in the frequency range previously reported for this species in the southwestern Atlantic Ocean. With the use of a higher sampling rate, the acoustic parameters of S. frontalis whistles have changed significantly and became more similar to those reported for North Atlantic populations. The article is open access and can be downloaded at: https://asa.scitation.org/doi/10.1121/10.0002637 Kind regards, Lis -- Lis Bittencourt Doutora em Oceanografia Laboratório de Mamíferos Aquáticos e Bioindicadores - MAQUA Universidade do Estado do Rio de Janeiro - UERJ Rua São Francisco Xavier, 524, 4º andar - sala 4002 bloco E Maracanã, Rio de Janeiro - RJ CEP 20550-013

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New publication on dolphin vertebral morphology
by María Constanza Marchesi 25 Nov '20

25 Nov '20

Dear colleagues, My co-authors and I are pleased to announce the publication of the following open access article in Frontiers in Marine Science: Marchesi MC, Mora MS, Dans SL, Coscarella MA and González-José R (2020) Vertebral Morphology in Partially Sympatric Dolphins: A 3D Approach. Front. Mar. Sci. 7:581762. doi: 10.3389/fmars.2020.581762 ABSTRACT: In cetaceans, increased body flexibility is associated with increased maneuverability, this affects the animal’s swimming speed and foraging behavior. A more stable body form is associated with fast swimming and wide turns. One factor that affects the flexibility of a cetacean’s body is the structure and interaction of its vertebrae. Differences in vertebral morphology confer different muscular insertion sites and affect mechanical properties of swimming muscles. We studied vertebral morphology in four closely related and partially sympatric dolphin species from the Southern Hemisphere: Commerson’s dolphin (Cephalorhynchus commersonii), Peale’s dolphin (Lagenorhynchus australis), the dusky dolphin (Lagenorhynchus obscurus) and the hourglass dolphin (Lagenorhynchus cruciger). The former two species are usually considered coastal, associated with complex habitats where foraging strategies require greater maneuverability; they also show plasticity in their prey preferences. The latter two species are considered fast-swimming cooperative feeders, with long distance movements reflecting prey availability in pelagic habitats. We employed three-dimensional (3D) geometric morphometric techniques and multivariate analyses to evaluate differences in vertebral morphology. Our analyses tested whether particular morphologies that limit or enhance flexibility were associated with preferred habitats and feeding strategies. We established links between morphology and behavioral patterns based on the biomechanical significance of specific vertebral morphological features. Principal component analyses (PCA) showed great differentiation between species in all the studied regions along the vertebral column. This was especially evident in the middle area, except in the case of dusky and hourglass dolphins which showed no discernible morphological difference in their mid-column vertebrae. PCA results were supported by statistically significant Mahalanobis distances (MD) between species. Species associated with complex habitats and behaviors possessed morphological features associated with greater flexibility of the column (i.e., spool-shaped vertebrae with short erect processes), whereas cooperative-feeder species possessed features associated with greater stability (i.e., disk-shaped vertebrae with long strongly bent processes). In these closely related and partially sympatric dolphins, vertebral morphology is distinctive and varies with the differential foraging strategies and habitat of each species. These findings reveal morphological plasticity among these dolphin species, highlighting the importance of behavioral complexity and of habitat use in the evolutionary development of morphological adaptations. <> You can find the article in the following link :https://www.frontiersin.org/articles/10.3389/fmars.2020.581762/full <https://www.frontiersin.org/articles/10.3389/fmars.2020.581762/full> For questions or comments please do not hesitate to contact me (marchesimc(a)gmail.com <mailto:marchesimc@gmail.com>) Regards Dra. María Constanza (Kata) Marchesi Becaria Posdoctoral / Postdoctoral fellow Laboratorio de Mamíferos Marinos (LAMAMA) Centro para el Estudio de los Sistemas Marinos (CESIMAR) CCT CONICET-CENPAT Blvd. Brown 2915 U9120ACD Puerto Madryn, Chubut, Argentina Phone: +54 280 488-3184/488-3185 (ext 1330) www.lamama.com.ar <http://www.lamama.com.ar/> Research Gate Profile: www.researchgate.net/profile/Maria_Constanza_Marchesi “Ever tried. Ever failed. No matter. Try again. Fail again. Fail better"

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New publication on depth inference of vocalizing fin whales using acoustic interference
by Andreia Pereira 25 Nov '20

25 Nov '20

Dear colleagues, My co-authors and I are pleased to announce the publication of the following article in JASA: Pereira, A., Harris, D., Tyack, P., and Matias, L. (2020). "On the use of the Lloyd's Mirror effect to infer the depth of vocalizing fin whales," The Journal of the Acoustical Society of America 148, 3086. ABSTRACT The interference between the direct path and the sea surface reflection of a signal as measured by a receiver is called Lloyd's Mirror effect (LME). It results in a frequency-dependent interference pattern that can be observed in a spectrogram. LME depends on the receiver depth, signal source depth, signal frequency, and slant range between source and receiver. Knowing three of these parameters a priori, LME can be used to estimate the third parameter, such as source depth. Here, the work in Pereira et al. (2016) was expanded to estimate the depth of a vocalizing fin whale recorded by an ocean-bottom seismometer (OBS). In Pereira et al. (2016), the depth of a vocalizing fin whale was inferred by manually comparing spectrograms of LME transmission loss models with observed LME. This study developed an automated procedure to perform the same task using the LME interference pattern observed in the spectrograms of the hydrophone and the vertical channel of the OBS. The results show that the joint use of the two channels was the best approach to estimate a source depth using LME. LME provides a non-intrusive approach for estimating the depth at which a fin whale was vocalizing. Please contact me for the full text and supplementary material and if you have any questions. You can also find the article in the following link: https://doi.org/10.1121/10.0002426 Best wishes, Andreia Pereira -- Andreia Pereira Research Fellow IDL - Instituto Dom Luiz Faculty of Sciences of the University of Lisbon Edifício C8 - Room 8.3.20 | Campo Grande | 1749-016 Lisboa | Portugal | +351966321466 ECCO Ocean https://ecco-ocean.com/ Associação para as Ciências do Mar https://cienciasmar.wixsite.com/associacao

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New publication: Protected area evaluation for Amazon River dolphins (Vanessa Mintzer)
by Mintzer,Vanessa J 24 Nov '20

24 Nov '20

New publication: Protected area evaluation for Amazon River dolphins (Vanessa Mintzer) Dear Colleagues, My co-authors and I are pleased to announce the publication of our new paper in Biological Conservation: "Protected area evaluation for the conservation of endangered Amazon river dolphins (Inia geoffrensis)." Citation: Mintzer, Vanessa J., Vera MF da Silva, Anthony R. Martin, Thomas K. Frazer, and Kai Lorenzen. "Protected area evaluation for the conservation of endangered Amazon river dolphins (Inia geoffrensis)." Biological Conservation 252 (2020): 108851.https://doi.org/10.1016/j.biocon.2020.108851 Shareable full-text: https://authors.elsevier.com/a/1c4EX1R%7EeIUjd<https://urldefense.proofpoint.com/v2/url?u=https-3A__authors.elsevier.com_a…> ABSTRACT: The potential value of protected areas for the conservation of cetaceans is widely recognized; however, few evaluation methods exist to assess their effectiveness. In this study, a modeling approach based on long-term mark-recapture/resight data was used to assess the effectiveness of a Brazilian reserve in protecting endangered Amazon River dolphins or boto (Inia geoffrensis), a species killed for use as fish bait. We built an annual discrete-time model with subdivisions based on hydrological periods and age classes. It included transition probabilities in and out of the reserve that were estimated utilizing multi-state mark-recapture models. To evaluate five reserve configurations, we re-estimated the transition probabilities to represent changes in the reserve boundaries. Model predictions showed that four scenarios, including one representing the existing boundaries, would be insufficient to protect the local boto population (no = 528) and a steep decline in abundance would occur in the next 50 years (0 ? n50 ? 108). However, one reserve configuration, encompassing both flooded forests and adjacent river habitats, and including beaches and channel/floodplain entrances, resulted in a nearly stable population in the same time frame (n50 = 515). These findings suggest that, with careful design and efficient management, protected areas could be an effective conservation tool for boto populations that exhibit site fidelity to Amazonian floodplains. With appropriate mark-recapture/resight data, the modeling framework employed could be extended to evaluate and design protected areas for populations of other species in other systems. Please reach out to me at vjs(a)ufl.edu<mailto:vjs@ufl.edu> with any questions. Thank you, Vanessa J. Mintzer, Ph.D. Wildlife Research Partnerships vanessamintzer.com Research Scientist Galveston Bay Dolphin Research Program Galveston Bay Foundation vmintzer(a)galvbay.org Courtesy Assistant Professor Fisheries and Aquatic Sciences Program School of Forest Resources and Conservation University of Florida vjs(a)ufl.edu ?

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New Publication: Sea otters and anthropogenic risk analysis in San Francisco Bay (Jane Rudebusch)
by Jane Anne Rudebusch 24 Nov '20

24 Nov '20

Dear friends and colleagues, On behalf of my co-authors, I am pleased to share our new Open Access paper published in PeerJ on informing sea otter reintroduction into San Francisco Bay through a spatial risk assessment of human-caused stressors in the region. The article is available here: https://peerj.com/articles/10241/ Assessing anthropogenic risk to sea otters (Enhydra lutris nereis) for reintroduction into San Francisco Bay Jane Rudebusch 1,2, Brent B. Hughes 3, Katharyn E. Boyer 1,4, Ellen Hines 1,2 1. Estuary & Ocean Science Center, San Francisco State University 2. Department of Geography and the Environment, San Francisco State University 3. Department of Biology, Sonoma State University 4. Department of Biology, San Francisco State University Southern sea otters have been actively managed for their conservation and recovery since listing on the federal Endangered Species Act in 1977. Still, they remain constrained to a geographically small area on the central coast of California relative to their former coast-wide range, with population numbers far below those of the estimated optimal sustainable population size. Species managers have discussed reintroducing southern sea otters into parts of their historic range to facilitate sustained population growth and geographic range expansion. San Francisco Bay (SFB), historically home to several thousand sea otters, is one location identified as a candidate release site for these reintroductions. The return of sea otters to SFB could bring benefits to local ecosystem restoration and tourism, in addition to spurring sea otter population growth to meet recovery goals. However, this is a highly urbanized estuary, so sea otters could also be exposed to serious anthropogenic threats that would challenge a successful reintroduction. In light of these potential detriments we performed a spatially-explicit risk assessment to analyze the suitability of SFB for southern sea otter reintroduction. We looked at threats to sea otters specific to SFB, including: the impacts of vessel traffic from commercial shipping, high-speed ferries, and recreational vessels; environmental contaminants of methylmercury and polychlorinated biphenyls; major oil spills; and commercial fishing. Factors that influenced the relative threat imposed by each stressor included the spatio-temporal extent and intensity of the stressor and its mitigation potential. Our analysis revealed the complex spatial and temporal variation in risk distribution across the SFB. The type and magnitude of anthropogenic risk was not uniformly distributed across the study area. For example, the central SFB housed the greatest cumulative risk, where a high degree of vessel traffic and other stressors occurred in conjunction. The individual stressors that contributed to this risk score varied across different parts of the study area as well. Whereas vessel traffic, particularly of fast ferries, was a high scoring risk factor in in the north and central bay, in the south bay it was environmental contaminants that caused greater risk potential. To help identify areas within the study area that managers might want to target for release efforts, the spatially-explicit risk map revealed pockets of SFB that could provide both suitable habitat and relatively low overall risk. However in some cases these were adjacent or in close proximity to identified high-risk portions of habitat in SFB. This predictive suitability and risk assessment can be used by managers to consider the spatial distribution of potential threats, and risk abatement that may be necessary for sea otters to re-occupy their historic home range in SFB. Questions or comments can be directed towards myself or Dr. Ellen Hines (ehines(a)sfsu.edu) Best, Jane Rudebusch Jane A. Rudebusch, M.S. jrudebus(a)mail.sfsu.edu

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New publication: Can dolphins decide to reduce their heart rate?
by Andreas Fahlman 23 Nov '20

23 Nov '20

Dear MarMamers My coauthors and I would like to share our new publication on conditioned heart rate responses in dolphins (https://www.frontiersin.org/articles/10.3389/fphys.2020.604018/abstract) In this study we show that the change in heart rate during diving varies depending on anticipation. This suggest that dolphins conditionally reduce their heart rate, and these results provide further evidence for the Selective Gas Exchange hypothesis (https://royalsocietypublishing.org/doi/full/10.1098/rspb.2018.0482) that explains how marine mammals can selective exchange oxygen and carbon dioxide without exchange of nitrogen and thereby maximize aerobic dive duration and also minimize the risk of the bends (see below for short video explaining this hypothesis). For more information, the title and abstract is below and also a link to the open access article. In addition, we have also included a video abstract of the paper, and also a link to an educational video explaining the Selective Gas Exchange hypothesis. If you have any questions, please do not hesitate to get in contact: afahlman(a)whoi.edu Title: Conditioned variation in heart rate during static breath-holds in the bottlenose dolphin (Tursiops truncatus) Authors: Fahlman,A., Cozzi, B., Manley, M., Jabas, S., Malik, M., Blawas A., and Janik, V.M.. DOI: 10.3389/fphys.2020.604018 URL: https://www.frontiersin.org/articles/10.3389/fphys.2020.604018/abstract Abstract: Previous reports suggested the existence of direct somatic motor control over heartrate (fH) responses during diving in some marine mammals, as the result of a cognitive and/or learning process rather than being a reflexive response. This would be beneficial for O2 storage management, but would also allow ventilation-perfusion matching for selective gas exchange, where O2 and CO2 can be exchanged with minimal exchange of N2. Such a mechanism explains how air breathing marine vertebrates avoid diving related gas bubble formation during repeated dives, and how stress could interrupt this mechanism and cause excessive N2 exchange. To investigate the conditioned response, we measured the fH-response before and during static breath-holds in three bottlenose dolphins (Tursiops truncatus) when shown a visual symbol to perform either a long (LONG) or short (SHORT) breath-hold, or during a spontaneous breath-hold without a symbol (NS). The average fH (ifHstart), and the rate of change in fH (difH/dt) during the first 20 s of the breath-hold differed between breath-hold types. In addition, the minimum instantaneous fH (ifHmin), and the average instantaneous fH during the last 10 s (ifHend) also differed between breath-hold types. The difH/dt was greater, and the ifHstart, ifHmin, and ifHend were lower during a LONG as compared with either a SHORT, or an NS breath-hold (P < 0.05). Even though the NS breath-hold dives were longer in duration as compared with SHORT breath-hold dives, the difH/dt was greater and the ifHstart, ifHmin, and ifHend were lower during the latter (P < 0.05). In addition, when the dolphin determined the breath-hold duration (NS), the fH was more variable within and between individuals and trials, suggesting a conditioned capacity to adjust the fHresponse. These results suggest that dolphins have the capacity to selectively alter the fH-response during diving and provide evidence for significant cardiovascular plasticity in dolphins. Video summary: https://www.youtube.com/watch?v=666zieqGv0A Explanation of the Selective Gas Exchange hypothesis: https://www.youtube.com/watch?v=sfBOpUuJv1c

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Workshop: distance sampling when animals are missed at zero distance, 11-12 Jan 2021
by Len Thomas 23 Nov '20

23 Nov '20

Training workshop on distance sampling when animals are missed at zero distance Registration is now open for our latest online interactive training workshop. Join us by video from anywhere around the world! For full details, and to register, please go to http://workshops.distancesampling.org/mrds-jan-2021.html Workshop Overview Conventional distance sampling methods assume that all animals at zero distance are detected with certainty. However, in some situations this assumption is violated, and some animals are missed, causing a negative bias in the density and abundance estimates. This occurs on some shipboard surveys of marine mammals, for example, where animals may be missed on the trackline because they are underwater while the survey vessel passes, or because the sea conditions are rough so that even some animals right on the line are missed. The former (being underwater and so not available for detection) is often called availability bias and the latter perception bias. In this two-day workshop, we cover survey protocols and analytical methods for dealing with both perception bias and availability bias. The workshop is intended for those already familiar with the basics of distance sampling. Instructors Len Thomas and David Borchers Centre for Research into Ecological and Environmental Modelling University of St Andrews Timing 11th and 12th January 2021 17:00-19:30 Grenwich Mean Time (GMT/UCT) // 12:00-14:30 Eastern Daylight Time (EDT) // 09:00-11:30 Pacific Daylight Time (PDT) Enrolment limit 15 participants Format and delivery method The workshop will be a mix of live online interactive sessions, delivered via videoconference software (Microsoft Teams), and computer exercises. There will be two sessions in total, on successive days, with a total class time of 5 hours (including breaks) and an additional computer exercise to complete after the first day and before the second. Exercises can be undertaken using Distance for Windows or R (via the mrds package). Other workshops We plan to offer a selection of introductory and more advanced/specialised workshops in 2021, via video conference. For more information, see https://workshops.distancesampling.org/

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Unpaid positions survey
by Phil Clapham 23 Nov '20

23 Nov '20

In an effort to gather some data on the reliance (or otherwise) of research projects on entry-level labor (paid or unpaid), I'd appreciate *directors of research projects* taking a few minutes to answer some questions about their experiences. I am particularly but not exclusively interested in projects operating as either small non-profits, or in developing countries (or both); but I'm interested to hear from anyone who is actively conducting marine mammal research *and* in a position to take on interns or other entry-level positions. Please email me at phillip.clapham(a)gmail.com and I'll send you the survey. Thanks. -- Phillip J. Clapham, Ph.D. Research Associate Smithsonian Institution National Museum of Natural History Senior Scientist Seastar Scientific Inc. Vashon Island, WA *"Science flies you to the moon. Religion flies you into buildings."* - Anon. *"The young know everything. Unfortunately, they don't know anything else." *- Anon.

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Funding opportunity
by Tim Werner 20 Nov '20

20 Nov '20

With support from NOAA-Fisheries, Ocean Associates and the Consortium for Wildlife Bycatch Reduction are pleased to announce the availability of funding to support competitive proposals focused on documenting or reducing marine mammal bycatch in non-US fisheries. To apply, please see: https://www.bycatch.org/content/funding-opportunities. Timothy B. Werner Senior Associate OAI Consulting Website: bycatch.org Twitter: @bycatch.org

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