Marine Mammal Commission

2023 Grant Awards

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Projects Funded by the Marine Mammal Commission in Fiscal Year 2023

Topic A: Research/Projects - Marine Mammal Health in a Changing Climate

Monitoring Florida manatee population health in a changing ocean: An evaluation of a practical surveillance system for a sentinel species

Burgess, L.

Anderson Cabot Center for Ocean Life, New England Aquarium

Over the past two decades, nine mass mortalities of the Florida manatee (Trichechus manatus latirostris) have been documented, resulting in the deaths of more than 2000 animals. Currently, an unusual mortality event (UME) along the east coast of Florida remains under investigation but appears to be related to the drastic loss of seagrass in the Indian River Lagoon (IRL). Manatees are increasingly at risk from both environmental and anthropogenic threats, including extreme cold temperatures, harmful algal blooms, dietary shifts to macroalgae, and watercraft strikes, which are compounded by habitat loss and destruction, and climate change. The ability to monitor physiologic responses of manatees to threats and identify changes, potentially before deleterious population consequences are observed, could greatly enhance management and mitigation efforts. Health assessments of wild manatees using capture techniques provide an enormous amount of valuable data; however, there remains an urgent need for a rapid surveillance tool to monitor and detect changes in manatee health at the population level (increasing sample size and accessibility in a cost-effective way). This project builds upon the development of a diverse panel of manatee fecal hormone assays to help monitor population health by providing indicators of stress, metabolic regulation, and reproduction, as well as a comprehensive endocrine reference dataset (seven different hormones) representing manatees in diverse known health states (+200 individuals sampled between 2003–2021). This project aims to critically evaluate the utility of using these new techniques to analyze manatee fecal samples as an early warning alert system to assess manatee population health.

Determining the relationship between prey, body condition and pregnancy in bowhead whales to predict the effects of climate change

Christiansen, F.

Aarhus University

The bowhead whale (Balaena mysticetus) is the largest predator in the Arctic and important for the marine ecosystem. With climate change having its most pronounced effect in the Arctic, it is important to understand how this will affect the bowhead whale, and consequently the Arctic marine environment. To address this knowledge gap, this project aims to determine the relationship between prey, body condition, and reproduction in bowhead whales in a major feeding area south of Disko Island, Greenland, during the spring of 2024. By using unmanned aerial vehicle (UAV) photogrammetry methods and biopsy sampling, changes in body condition (relative fatness) of bowhead whales will be measured through the feeding season relative to sex and pregnancy status. Long-term zooplankton data will be used to relate the rate of increase in body condition of bowheads (measured by the UAV) to the prey density in the area. Long-term fine-scale movement data from archival tags and regional movement data from satellite tags will be used to build a bioenergetic model of bowhead whales to relate prey density to foraging behaviour, body condition, and reproduction (pregnancy). Finally, from existing climate models (predictions of sea ice coverage and sea surface temperature), how changes in prey availability caused by climate change will be assessed to determine the effect on future body condition of bowhead whales, and its consequences on reproduction (pregnancy). With many marine top predators facing similar threats from climate change, this project will help guide current research and highlight the sensitivity of Arctic predators to environmental changes caused by climate change.

Bridging research efforts to optimize body condition evaluation in two beluga (Delphinapterus leucas) populations: Blubber stratification and use of “omics” techniques to identify biomarkers of body condition

Lair, S.

Université de Montréal

The East Beaufort Sea (EBS) beluga (Delphinapterus leucas) population is stable and of critical importance to the Inuvialuit and Inuit people of western Canada and Alaska. At the southernmost portion of the species range, the endangered St. Lawrence Estuary (SLE) beluga population is declining and faces multiple threats to its recovery, such as prey limitation, toxic contaminants and ocean noise. Despite their differing status, both beluga populations face a common threat: environmental perturbations resulting from climate change, which have the potential to negatively impact the EBS population and compound the existing threats to the SLE population. While both beluga populations have been studied extensively for four decades, knowledge gaps persist, including the ability to accurately and effectively evaluate body condition (BC). Bridging knowledge gathered for each population can remediate this. EBS beluga morphometrics and tissue samples will be collected through veterinarian-led post-mortem examinations performed as part of a health assessment over the 2023 and 2024 subsistence hunts. Longitudinal information collected on blubber stratification will help to better understand blubber morphometrics in relationship with BC in belugas. The utility of skin and outer blubber lipidomic and transcriptomic as biomarkers of BC will be assessed using the EBS belugas as a proxy for the SLE population, for which samples in free-ranging animals are limited to biopsies. This project aims to develop a minimally invasive method to assess body condition in SLE belugas. Given the rapidly occurring and inevitable impacts of climate change on marine mammal populations, this collaborative project will optimize the collection of data needed to inform the future management of these two populations.

Baleen biochemistry to understand North Atlantic right whale health in the context of climate change

Lysiak, N.

New England Aquarium

North Atlantic right whales (NARWs) experience a myriad of stressors, including human interactions that lead to mortality, serious injury, and morbidity. Their reproductive rate is depressed, with many adult females experiencing longer calving intervals in recent years. The result is a population in decline. Simultaneously, climate change and ocean warming have caused shifts in both Calanus finmarchicus and NARW distribution. While NARWs are a well-studied population, there are major knowledge gaps in the extent to which anthropogenic and natural stressors impact individual health, nutritional state, and fecundity. Baleen is a tissue that holds multi-year, individual ecological and physiological records, accessible through measuring carbon and nitrogen stable isotopes and hormones (progesterone, estrogen, testosterone, cortisol, corticosterone, and thyroid) in longitudinal samples. This study aims to analyze baleen plates to create comprehensive biochemical records from each individual whale that will be compared to its known sighting and reproductive histories. This dataset will enable an assessment of: 1) how anthropogenic interactions impact the health and reproduction of individuals, 2) how climate change has influenced the nutritional state and reproductive success of the NARW population.

Developing a standardized assessment protocol for visual characterization of skin lesions associated with freshwater exposure in common bottlenose dolphins (Tursiops truncatus)

Mintzer, V.

Galveston Bay Dolphin Research Program

Exposure to low salinity water is an emerging critical health issue for bay, sound, and estuarine dolphin populations. As a result of global climate change, the intensity and frequency of storms causing heavy precipitation and flood events is increasing. This will lead to more frequent freshwater fluctuations and corresponding low-salinity events in estuarine systems. The need to advance the assessment of skin lesions as an indicator of health issues associated with freshwater exposure has been identified in the literature. This project aims to hold a collaborative workshop to create a standardized protocol to visually assess the skin condition of common bottlenose dolphins (Tursiops truncatus) using photographs taken during photo-identification surveys. With the input of federal managers, veterinary pathologists, and field researchers, a standardized method for identifying and quantitatively assessing freshwater skin disease, and other relevant associated conditions, will be developed. By standardizing the visual assessment of severity and progression of skin lesions associated with freshwater exposure in free-ranging dolphins, this protocol will be an important first step to advance knowledge of climate-driven salinity fluctuations affects on marine mammal health.

Physiological impact of climate change across decades on the sentinel species of Antarctica, the crabeater seal (Lobodon carcinophaga)

Tift, M.

University of North Carolina, Wilmington

The western Antarctic Peninsula (wAP) has experienced some of the greatest rates of warming in the world due to anthropogenic climate change. The effects of environmental warming have already been observed on species such as Antarctic krill, and these changes are expected to intensify as temperatures continue to increase. Crabeater seals are particularly vulnerable to shifts in Antarctic krill as they are extreme specialists with their average diet consisting of more than 87% krill. Additionally, crabeater seals are an ice-obligate species, meaning they require sea ice for resting, mating, and molting. The ability of the crabeater seal to withstand both environmental stressors and shifts in their major prey species is not well understood. Current modeling predicts crabeater seals may shift their habitat further south along the wAP to avoid decreased sea ice concentrations and krill abundance. However, the physiological response of crabeater seals is unknown. This projects aims to gain an insight into how crabeater seals have been affected by these stressors by examining hormones in inert tissues such as whiskers and teeth. A novel method to measure stress (cortisol, corticosterone) and reproductive (estradiol, testosterone, progesterone) hormones from historical crabeater seal teeth collected from 1950-1990s using liquid chromatography tandem mass spectrometry will be developed. Additionally, the same reproductive and sex hormones in whiskers collected from crabeater seals in 2007, 2022 and 2023 will be analyzed. These hormones will be related to sea-ice concentration and krill abundance from the National Snow and Ice Data Centre and KRILLBASE, respectively. This analysis provide a better understanding of the physiological response of crabeater seals to environmental stressors. Additionally, this study will help to predict how crabeater seals will respond to future perturbations not only in the wAP, but across Antarctica.

A decadal assessment of gray whale prey, body condition and vital rate response to environmental change

Torres, L.

Oregon State University

It is critical to understand how climate change will impact the availability of prey to marine mammals, and consequently how these changes will impact predator health and population vital rates. Photogrammetry of images collected from Unoccupied Aircraft Systems (UAS) has become a popular and effective approach to quantify body condition of baleen whales as a proxy for foraging success under the assumption that environmental variability regulates prey availability to which whales respond physiologically. This project aims to prove this assumption and justify calls to monitor environmental conditions associated with body condition, which would enable responsive conservation management. Gray whale foraging data collected from 2016- 2026 along the Oregon, USA coast will be analyzed, including paired environmental (e.g., broadscale: climatic indices; mesoscale: upwelling indices; fine scale: insitu data), prey availability, and individual body condition data, with associated demographic information. Analysis of this unique dataset will allow for the assessment of how health (body condition) and vital rates (growth and pregnancy rates) are influenced by climate-driven variability on prey availability to improve the understanding of environmental drivers, vulnerable demographic units, and time lags of population response. Analytical methods will be developed using artificial intelligence to quantify relative prey abundance from recreational echosounder data, which is often collected but rarely utilized. This research will improve not only gray whale population management, but also inform health surveillance methods, population assessments, and conservation management of other baleen whale populations in the face of climate change.

Out of Cycle Award

Support for southern right whale (Eubalaena australis) unusual mortality event emergency response in Argentina September – October 2022

M. Sironi & M. Uhar

Instituto de Conservacion de Ballenas

Between September – October 2022, at least 30 dead adult and juvenile southern right whales were documented in Argentina. This award supports the emergency response to this unusual mortality event, including surveys for stranded whales, necropsy response, and analysis of samples to investigate cause of death.