Marine Mammals
Marine Mammals
Marine mammals are a diverse group of animals that depend on marine environments for all or much of their lives. They include whales, dolphins and porpoises; seals, sea lions and walruses; sea otters; manatees and dugongs; and polar bears. Although these animals evolved from terrestrial ancestors, they have developed remarkable adaptations for swimming, diving, feeding, communication, thermoregulation and reproduction in aquatic environments.
Marine mammals occupy ecosystems ranging from tropical seagrass meadows and coral-rich coastal waters to productive temperate seas and the ice-covered Arctic. They include some of the largest animals that have ever lived as well as small coastal species occupying highly specialized habitats. Their ecological roles are equally diverse, encompassing predators, grazers, nutrient transporters and ecosystem engineers.
Diversity, Ecology, and Behavior
Marine mammals display extraordinary differences in body size, feeding strategy, movement and social organization. Baleen whales filter enormous quantities of small prey from seawater, while toothed whales and dolphins pursue fish and squid using sophisticated acoustic senses. Sea otters influence coastal food webs through predation, dugongs and manatees graze aquatic vegetation, and polar bears depend heavily on marine mammals and sea-ice ecosystems for food.
Many species undertake extensive seasonal migrations between feeding and breeding areas. Humpback, blue, gray, bowhead and other whales may travel thousands of kilometers each year. Other species, including some dolphins, seals and walruses, demonstrate strong fidelity to particular feeding, breeding or resting areas.
Research increasingly shows that marine mammals possess complex social behavior and communication. Dolphins use individually distinctive signals, whales produce elaborate vocalizations, and some populations appear to transmit feeding techniques and other behaviors socially. Observations of dolphins using objects as tools and coordinated hunting by killer whales illustrate the behavioral flexibility found within the group.
Marine mammals also have major ecological effects. Sea otters can restructure coastal ecosystems through their effects on prey populations, while whales transport nutrients between feeding and breeding regions. Carcasses of whales and other large marine mammals provide concentrated sources of food and nutrients for scavengers and deep-sea communities.
Climate Change and Changing Oceans
Climate change is altering marine-mammal habitats across the world. Rising ocean temperatures, marine heatwaves, changing currents and shifting prey populations can affect where animals feed, migrate and reproduce. Several studies in the collection show that major marine heatwaves can produce substantial changes in whale populations and other marine ecosystems.
Arctic species face particularly rapid environmental change. Declining sea ice alters habitat available to polar bears, seals, walruses and Arctic whales. Reduced ice can change access to prey, migration routes, breeding habitat and interactions among species while simultaneously allowing greater shipping and other human activity in formerly inaccessible waters.
Changes in ocean productivity can also affect marine mammals far from the polar regions. Gray whales, humpback whales, seals, sea lions and dolphins may experience nutritional stress when prey becomes less abundant or moves into different regions. Long-lived marine mammals can therefore act as indicators of broader changes occurring throughout marine food webs.
Harmful algal blooms are another growing concern. Toxins produced by some blooms can move through marine food webs and accumulate in marine mammals. Research has detected algal toxins in stranded whales and documented exposure among whales, sea lions and other species.
Fishing, Vessel Strikes, and Human Activity
Accidental capture and entanglement in fishing gear remain among the most serious human-caused threats to marine mammals. Whales, dolphins, porpoises and seals may drown immediately or suffer prolonged injuries, infections, starvation and exhaustion after becoming entangled.
North Atlantic right whales illustrate the severity of this problem. With only a small population remaining, deaths caused by fishing gear and vessel strikes can significantly affect the species' prospects for recovery. Similar conflicts occur in many other regions where marine mammals overlap with intensive fishing.
Ship strikes are especially dangerous for large whales. Blue, fin, humpback, gray and right whales frequently travel through waters crossed by major commercial shipping routes. Research has shown that vessel speed strongly affects the probability that a collision will cause serious injury or death, leading to proposals for speed restrictions and changes in shipping routes.
New technologies may help reduce these risks. Thermal cameras, acoustic monitoring systems, autonomous instruments and other detection systems can identify whales near shipping lanes and provide information to vessels and resource managers. Modifications to fishing gear, including ropeless systems and acoustic devices, are also being investigated as ways of reducing entanglement and bycatch.
Underwater Noise and Industrial Development
Sound is central to the lives of whales and dolphins. Many species depend on acoustic signals for communication, navigation, locating prey and maintaining social relationships. Human activities have added substantial amounts of noise to the marine environment.
Shipping, naval sonar, seismic surveys, offshore construction and other industrial activities can interfere with marine-mammal communication or alter animal behavior. Research has documented changes in whale and dolphin distribution, vocalization, feeding and movement during exposure to intense or persistent human-generated sound.
Scientists increasingly seek to understand cumulative effects rather than examining isolated disturbances. An animal repeatedly displaced from feeding habitat or forced to spend additional energy because of disturbance may eventually experience consequences for body condition, reproduction or survival even when individual encounters do not cause obvious injury.
Offshore energy development introduces additional questions. Studies of offshore wind installations and other marine construction examine not only construction noise but also vessel traffic, habitat alteration and changes in prey communities.
Pollution and Disease
Marine mammals accumulate pollutants from their environment and food. Persistent chemicals can reach high concentrations in long-lived predators, while research has also found evidence of microplastic exposure in whales, dolphins, seals and other marine mammals.
Plastic pollution can injure animals directly through ingestion or entanglement. Studies of stranded wildlife indicate that even relatively small quantities of ingested plastic can sometimes produce serious gastrointestinal damage.
Infectious disease is another important source of mortality. Research in the collection documents bacterial, viral and other infections among dolphins, sea otters, seals and whales. Disease surveillance is increasingly incorporated into stranding investigations and population monitoring.
Avian influenza has emerged as a particularly important concern. H5N1 has spread from birds into marine mammals in several regions. Cases among seals and other marine mammals demonstrate how rapidly changing disease dynamics can create new conservation challenges.
Conservation and Protected Areas
Marine-mammal conservation has expanded considerably beyond efforts to regulate commercial whaling. Modern programs address entanglement, vessel strikes, pollution, underwater noise, disease, habitat degradation, tourism, climate change and other cumulative pressures.
Marine protected areas can provide important habitat, but their effectiveness depends on how closely their boundaries correspond with actual animal movements and ecological needs. Highly mobile species frequently travel beyond protected boundaries, requiring conservation strategies that operate across larger regions and sometimes across national borders.
Important Marine Mammal Areas and other science-based conservation frameworks identify habitats used for feeding, breeding, migration and other essential activities. Tracking studies involving hundreds of researchers have further revealed global networks of important habitat for mobile marine animals.
Successful protection often requires cooperation among governments, researchers, fishing communities, shipping companies, Indigenous communities and conservation organizations. Local and Indigenous ecological knowledge can provide information that complements scientific surveys, particularly in remote regions where long-term observations are otherwise scarce.
Research and Monitoring Technologies
Marine-mammal science increasingly relies on a combination of field observation and advanced technology. Satellite tags and animal-borne sensors allow scientists to follow movements, dives and feeding behavior that cannot be observed from the surface.
Passive acoustic monitoring has become especially important. Underwater microphones can detect whales, dolphins and other vocal species continuously, including at night, during poor weather and in remote regions. Long-term acoustic datasets reveal seasonal movements and habitat use that visual surveys may miss.
Drones provide researchers with another powerful tool. Aerial photographs can be used to estimate body condition, count animals, identify calves and observe behavior while reducing the need for close approaches by boats. Researchers are also developing drone-assisted methods for attaching temporary scientific tags.
Environmental DNA provides a different way of detecting marine life. Genetic material collected from seawater can reveal which species have recently occupied an area and may eventually help scientists examine population structure and genetic diversity.
Autonomous gliders, acoustic buoys, ocean-bottom instruments, artificial intelligence, thermal cameras and portable molecular diagnostic systems are further expanding the ability to monitor marine mammals and respond quickly to conservation threats.
Strandings and What They Reveal
Stranded marine mammals provide scientists with valuable information about ocean health. Necropsies can reveal evidence of disease, starvation, harmful algal toxins, fishing interactions, vessel strikes, plastic ingestion and other causes of mortality.
Long-term stranding networks allow researchers to identify patterns that might otherwise remain invisible. Increases in deaths of a particular whale, dolphin or seal population can provide early warning of ecological disruption.
Strandings also create logistical and ethical challenges. Large whale carcasses can be difficult to examine or remove, while naturally decomposing carcasses can themselves provide important nutrients and habitat for coastal and deep-sea organisms.
Marine Mammals and People
Human relationships with marine mammals extend from subsistence and cultural traditions to tourism, scientific research and wildlife conservation. Whale watching and dolphin tourism can encourage public interest in conservation but may also disturb animals when vessels or swimmers approach too closely.
Effective wildlife tourism therefore requires management that balances educational and economic benefits with animal welfare and disturbance reduction.
Marine mammals are also important to many Indigenous and coastal communities. Collaborative research increasingly recognizes that local observations accumulated over generations can substantially improve scientific understanding of marine ecosystems.
The history of marine-mammal conservation demonstrates that populations can recover when major sources of mortality are reduced. Sea otters, humpback whales and several other populations have shown substantial recovery under effective protection. At the same time, species such as the vaquita and North Atlantic right whale demonstrate how quickly populations can approach extinction when threats remain unresolved.
Conclusion
Marine mammals are among the most visible inhabitants of the world's oceans, but their importance extends well beyond their public appeal. As predators, grazers, nutrient transporters and indicators of ecosystem change, they are deeply integrated into marine food webs and ocean processes.
The research summarized here shows that marine mammals face multiple interacting pressures rather than any single conservation problem. Climate change can shift prey and habitat while also increasing exposure to ships, disease and human activity. Fishing gear, vessel traffic, pollution and underwater noise can further compound these pressures.
At the same time, marine-mammal science is entering an era of increasingly sophisticated observation. Acoustic networks, drones, satellite tracking, environmental DNA, autonomous vehicles and artificial intelligence are making it possible to observe animals and ecosystems at scales that were previously impossible.
Protecting marine mammals therefore depends on combining long-term scientific monitoring with effective management of fisheries, shipping, pollution, habitat and climate-related risks. Their future will be closely connected to the broader health and resilience of the oceans themselves.
Disease and Marine Mammal Health
| Reuters | Reuters | 2026-08-23
Australia confirmed H5N1 avian influenza in a long-nosed fur seal, the country's first detected case of the virus in a native mammal and a warning about the disease's growing threat to marine mammals.
| Guardian staff | The Guardian | 2026-08-23
The death of a fur seal from H5 bird flu on mainland Australia raised concerns that the virus could cause severe losses among vulnerable seal and sea-lion populations.
| Florida Atlantic University | ScienceDaily | 2026-07-21
Researchers identified previously unknown Helicobacter bacteria in stranded pygmy sperm whales with severe gastrointestinal disease.
| Margaret E. Martinez et al. | Frontiers in Marine Science | 2026-07-20
Fatal leptospirosis in southern sea otters documents an infectious-disease threat to California's recovering otter population.
| UH News | University of Hawaiʻi | 2026-03-30
A portable molecular testing system can identify cetacean morbillivirus in the field in about an hour.
| The Marine Mammal Center | The Marine Mammal Center | 2026-02-26
H5N1 avian influenza was confirmed in northern elephant seals and other California marine mammals, prompting temporary rescue restrictions.
| UH News | University of Hawaiʻi | 2025-12-21
An 18-year review of Pacific whale and dolphin strandings found infectious disease and human-caused trauma in most investigated cases.
| UH News | University of Hawaiʻi | 2025-06-23
Striped-dolphin strandings in Hawaiʻi were linked to Brucella ceti, emphasizing disease surveillance and risks to responders.
| Tim Vernimmen | Mongabay | 2023-02-16
H5N1 outbreaks in Peru spread from seabirds into marine mammals, foreshadowing later global concerns about mammalian transmission.
| Michael J. Moore et al. | Diseases of Aquatic Organisms | 2021-02-25
A comprehensive review examines North Atlantic right-whale health, major threats, and the increasingly sophisticated tools scientists use to monitor individual whales.
Pollution, Toxins, and Contaminants
| Lorelei Hoffman Schwacke et al. | Frontiers in Marine Science | 2026-08
Research links PCB exposure with health, reproductive, and mortality risks in bottlenose dolphins from the southeastern United States.
| Mike Peña | UC Santa Cruz | 2026-06-12
Tests on stranded humpback whales in California detected domoic acid, illustrating how harmful algal blooms can become a serious health threat to marine mammals.
| Anaïs Remili and Tanya Brown | Phys.org / The Conversation | 2026-05-22
Molecular evidence shows persistent contaminants are affecting ringed seals already challenged by Arctic warming.
| Authors listed in article | Communications Earth & Environment | 2026-04-13
A harmful algal bloom in Argentina transferred toxins through the food web to southern right whales and sea lions, including fetal exposure.
| International Whaling Commission | IWC | 2026
Modern whale conservation extends far beyond whaling regulation to address entanglement, ship strikes, underwater noise, marine debris, pollution, strandings, and whale watching.
| The Marine Mammal Center | The Marine Mammal Center | 2026
Current rehabilitation records provide a real-time picture of disease, malnutrition, trauma, and toxin exposure among seals, sea lions, fur seals, and sea otters.
| Mongabay | Mongabay | 2025-11
Large datasets from stranded animals show that relatively small amounts of ingested plastic can cause fatal gastrointestinal damage in marine mammals.
| Ariane B. Barrette et al. | Scientific Reports | 2025-10-14
Beluga tissues contain high levels of selenium-related antioxidants that may also contribute nutritionally to traditional Inuit diets.
| Kathi A. Lefebvre et al. | Nature | 2025-07-09
Long-term bowhead-whale samples show rising exposure to algal toxins as Arctic waters warm.
| Mongabay | Mongabay | 2025-04
Fifteen years after Deepwater Horizon, dolphins and several whale species in the Gulf of Mexico continue to show long-term impacts.
| Authors listed in article | Environmental Pollution | 2023
Microplastics were detected in internal tissues including blubber from marine mammals, suggesting that very small plastic particles can move beyond the digestive tract.
| Authors listed in article | Environmental Pollution | 2021
A systematic review found widespread evidence of microplastic exposure among whales, dolphins, seals, and other marine mammals while highlighting major gaps in research methods.
| R. C. Moore et al. | Marine Pollution Bulletin | 2020-01
Microplastics were found in every beluga whale examined from the eastern Beaufort Sea, demonstrating that plastic pollution reaches Arctic marine food webs.
Climate Change, Habitat, and Food Webs
| The Guardian | The Guardian | 2026-08-17
Intensifying marine heatwaves are reorganizing British marine ecosystems, altering prey communities and the distribution of marine mammals including dolphins.
| Mišo Pavičić et al. | Frontiers in Marine Science | 2026-08-05
Changes in fish communities are evaluated in relation to prey availability for the endangered Mediterranean monk seal.
| Samantha Garrard | Phys.org / The Conversation | 2026-06-17
A strong El Niño can disrupt marine food webs and leave seals and sea lions struggling to find enough prey.
| John R. Moran et al. | Marine Mammal Science | 2026-05-03
Humpback whale numbers in Prince William Sound declined following the severe 2014–2016 Northeast Pacific marine heatwave, linking marine mammal population change with ecosystem disruption.
| Jon Aars et al. | Scientific Reports | 2026-01-29
Long-term research on Svalbard polar bears examines body condition during a period of rapid sea-ice loss and provides insight into how Arctic predators respond to environmental change.
| Vera Metcalf et al. | Arctic Science | 2025-10-09
Researchers combined scientific and Indigenous knowledge to improve understanding of Pacific walruses and the ecological changes occurring as Arctic sea ice declines.
| David Helvarg | Mongabay | 2025-10-09
California's marine mammals have recovered substantially under federal protection but face growing threats from climate change, pollution, disease, and policy shifts.
| Authors listed in article | Marine Policy | 2025-10
Spatial modeling suggests that much important dugong habitat in the Indo-Pacific lies outside existing marine protected areas and is increasingly threatened by climate change and human activity.
| Caitlin B. Harris et al. | Marine Pollution Bulletin | 2025-09
A review evaluates how rapidly expanding floating offshore wind development could affect marine mammals directly and through changes in prey and marine food webs.
| UH News | University of Hawaiʻi | 2025-06-08
Researchers explain the energetic demands of the Alaska-to-Hawaiʻi humpback migration and how marine heatwaves may affect reproduction.
| Lillian Draper Parker et al. | Scientific Reports | 2025-02-17
Archaeological polar-bear remains from Alaska's Aleutian Islands provide evidence about historical sea-ice conditions and changing marine-mammal distributions.
| Ryan R. Wilson and Erik M. Andersen | Scientific Reports | 2025-02-10
Researchers examine uncertainties in attempts to connect greenhouse-gas emissions quantitatively with changes in polar-bear demographic rates.
| Devin L. Johnson et al. | Journal of Wildlife Management | 2025
Population modeling examines the sustainability of Pacific walrus harvest as sea-ice loss transforms walrus habitat and behavior.
| L. Mikkelsen et al. | Scientific Reports | 2024
GPS tracking showed that male Svalbard walruses repeatedly return to the same seasonal areas despite large year-to-year variation in sea ice.
| Authors listed in article | Arctic Science | 2024
Earlier sea-ice retreat in Hudson Bay was associated with lower survival in some age classes of male polar bears, illustrating demographic consequences of changing ice conditions.
| Elizabeth Claire Alberts | Mongabay | 2023-05-23
Research links reduced Arctic sea ice with changing timing and routes of bowhead-whale migrations.
| Authors listed in article | Arctic Science/Polar Geography research | 2023
Evaluation of the Sea Ice for Walrus Outlook shows how scientific information and Indigenous knowledge can support communities responding to changing Arctic sea ice.
| Authors listed in article | Global Change Biology | 2017
Polar-bear feeding success was examined in relation to sea ice, prey productivity, and broader ecosystem conditions in the Beaufort and Chukchi Seas.
| Kit M. Kovacs et al. | Science Progress | 2008-07
Declining sea ice is expected to alter breeding habitat, prey, competition, disease exposure, and human activity affecting Arctic seals and whales.
| Sue E. Moore and Huntington | Ecological Applications | 2008
Arctic whales, seals, walruses, and polar bears differ greatly in their dependence on sea ice and therefore in their likely vulnerability to a warming Arctic.
Fisheries, Bycatch, and Entanglement
| Russell Parton | Phys.org | 2026-08-13
Postmortems of stranded common dolphins in Cornwall identify fisheries bycatch as the leading known cause of death.
| NOAA Fisheries | NOAA Fisheries | 2026-07-29
Blue whales remain endangered despite decades of protection, with ship strikes, entanglement, ocean noise, habitat change, and prey availability among continuing conservation concerns.
| NOAA Fisheries | NOAA Fisheries | 2026-07-29
North Atlantic right whales number only a few hundred animals, making the reduction of fishing-gear entanglements and vessel strikes critical to the species' recovery.
| Frontiers | Phys.org | 2026-07-03
Bottlenose dolphins in parts of the Adriatic frequently follow trawlers, suggesting heavy reliance on fishing activity for food.
| Newcastle University | Phys.org | 2026-07-02
Simple acoustic reflectors made from plastic bottles reduced dolphin bycatch in experimental fishing-net trials.
| The Guardian | The Guardian | 2026-06-10
An analysis of British fisheries estimated that bycatch kills large numbers of dolphins, porpoises, seals, and whales and highlighted the potential of monitoring and fishing-gear reforms.
| NOAA Fisheries | NOAA Fisheries | 2026-04-09
Humpback whale recovery has been substantial in many regions, but some populations remain endangered and face entanglement, ship-strike, disturbance, and habitat threats.
| NOAA Fisheries | NOAA Fisheries | 2026
Dolphins and porpoises are important marine predators and ocean-health indicators that face threats from bycatch, noise, pollution, habitat degradation, and climate change.
| NOAA Fisheries | NOAA Fisheries | 2025
Entanglement in fishing gear can cause drowning, starvation, infection, exhaustion, and long-term injury in whales, dolphins, porpoises, and seals.
| IWC Scientific Committee | International Whaling Commission | 2024
Scientific modeling supports the conclusion that reducing entanglements and ship strikes could substantially improve the survival prospects of North Atlantic right whales.
| Maxwell Radwin | Mongabay | 2023-05-30
The United States concluded that Mexico had not done enough to enforce protections intended to prevent vaquita deaths in illegal gillnets.
| IWC Scientific Committee | International Whaling Commission | 2023
The IWC identifies ship strikes and fishing-gear entanglement as the principal human-caused mortality threats to North Atlantic right whales.
| John Cannon | Mongabay | 2022-09-21
Ropeless fishing technologies are being developed to reduce the vertical lines responsible for many whale entanglements.
| James V. Carretta and Allison G. Henry | Frontiers in Marine Science | 2022-06-24
Researchers developed methods for evaluating the severity and likely outcomes of whale injuries caused by fishing-gear entanglements and vessel strikes.
| Mike Meÿer et al. | Journal of Cetacean Research and Management | 2022
Records of southern right whales in South Africa document mortalities, entanglements, and ship strikes and help identify areas where continued monitoring is needed.
| Andrew M. Gormley and Elisabeth Slooten | Journal of Applied Ecology | 2012-03-27
Long-term monitoring of Hector's dolphins provided evidence that a marine mammal sanctuary restricting gillnet fishing improved dolphin survival.
| Amy R. Knowlton and Scott D. Kraus | Journal of Cetacean Research and Management | 2001-12-01
Historical records of North Atlantic right whales show how ship strikes and fishing-gear entanglements prevented recovery of an already extremely small population.
| Woods Hole Oceanographic Institution | WHOI | n.d.
An accessible overview explains the major marine-mammal groups, their adaptations to ocean life, ecological roles, and threats from fishing gear, ships, and underwater noise.
Vessel Strikes and Shipping
| Sarah Kuta | Smithsonian Magazine | 2026-07-13
A surge of gray-whale deaths along North America's Pacific coast highlights concerns over malnutrition, ecosystem change, and ship strikes.
| Olivia Ferrari | Smithsonian Magazine | 2026-06-26
The article examines evidence that vessel speed limits reduce deadly collisions with critically endangered North Atlantic right whales.
| Sarah Kuta | Smithsonian Magazine | 2026-06-25
AI-assisted thermal cameras are being used to detect gray whales in San Francisco Bay and warn nearby vessels.
| Angela R. Szesciorka et al. | Frontiers in Marine Science | 2026-06-09
Declining sea ice changes bowhead-whale distribution and increases overlap with vessel traffic in the Pacific Arctic.
| Julia Saltzman et al. | npj Ocean Sustainability | 2026-02-24
A global synthesis quantifies how vessel traffic affects whales, dolphins, seals, manatees, and other marine megafauna.
| NOAA Fisheries | NOAA Fisheries | 2026
Vessel collisions are a major source of mortality for large whales, particularly where productive whale habitat overlaps with busy shipping corridors.
| The Marine Mammal Center | The Marine Mammal Center | 2026
Necropsy and stranding records from California document gray- and humpback-whale deaths, including suspected vessel strikes and predation.
| NOAA Fisheries | NOAA Fisheries | 2025
Blue, fin, humpback, and gray whales are particularly vulnerable where major West Coast shipping routes overlap with migration and feeding areas.
| Malaka Rodrigo | Mongabay | 2022-10-30
Moving a major shipping lane away from Sri Lanka's blue-whale habitat could sharply reduce collision risk.
| David W. Laist et al. | Marine Mammal Science | 2001
A foundational analysis of whale collisions found that ship speed is an important factor in the severity of vessel strikes and identified vulnerable whale populations.
| Woods Hole Oceanographic Institution | Robots4Whales | n.d.
Autonomous gliders and acoustic buoys detect whale calls in near real time, providing data that can help ships and managers reduce collision risks.
| International Whaling Commission | IWC | n.d.
The IWC describes vessel strikes as a global and frequently underreported threat to whales and coordinates international efforts to identify high-risk areas and mitigation measures.
Ocean Noise and Industrial Disturbance
| Authors listed in article | Frontiers in Conservation Science | 2026-07-29
Pantropical spotted and spinner dolphins altered acoustic signals when exposed to seismic airgun noise.
| Longfei Huang and Xiaomei Xu | Frontiers in Marine Science | 2026-07-29
Researchers characterize free-falling crushing as a potentially important but underrecognized source of construction noise affecting marine mammals.
| Alba Solsona-Berga et al. | Scientific Reports | 2026-06-25
Long-term acoustic research suggests Cuvier's beaked whales may alter their responses in regions repeatedly exposed to naval sonar.
| Shanna Hanbury | Mongabay | 2026-06-12
Shipping noise in the Strait of Gibraltar can mask long-distance calls used by long-finned pilot whales.
| Kim Nina Heimberg et al. | Scientific Reports | 2025-09-15
Researchers tested acoustic deterrents as a way to reduce conflicts between seals and people at a German swimming beach.
| NOAA Fisheries | NOAA Fisheries | 2025
Passive acoustic research allows scientists to identify marine mammals and measure how shipping, construction, seismic surveys, and other human sounds overlap with animal communication.
| Mary Jo Barkaszi and Christopher J. Kelly | PLOS ONE | 2024-03-21
A massive dataset from Gulf of Mexico seismic surveys was analyzed to determine how marine mammals respond to airgun activity and how useful observer programs are for assessing disturbance.
| Authors listed in article | Ocean & Coastal Management | 2023-11-01
Scientists review methods for measuring the effects of seismic surveys and other marine industrial activities on baleen whales.
| Alice Affatati and Angelo Camerlenghi | Frontiers in Marine Science | 2023-09-20
A systematic review summarizes research on how seismic surveys affect free-ranging marine animals, with marine mammals making up much of the available evidence.
| Elizabeth Claire Alberts | Mongabay | 2023-07-06
A U.N.-linked report reviews technologies and management strategies for reducing underwater noise from ships and other human activities.
| Elizabeth Claire Alberts | Mongabay | 2023-02-14
Scientists warn that deep-sea mining could expose whales and other cetaceans to noise and habitat disruption that remain poorly studied.
| Authors listed in article | Environmental Monitoring and Assessment | 2022
Real-time acoustic monitoring was tested as a way to reduce the effects of seismic-survey noise on western gray whales feeding near Sakhalin Island.
| A. S. Kavanagh et al. | Scientific Reports | 2019-12-16
Cetacean sightings declined substantially during active seismic surveys across a large Northeast Atlantic marine ecosystem, indicating broad behavioral responses to industrial noise.
| Shima H. Abadi et al. | Journal of the Acoustical Society of America | 2015-12
Researchers developed techniques for locating calling whales using equipment deployed during marine seismic surveys.
| NOAA Fisheries | NOAA Fisheries | 2013
Whales and dolphins depend heavily on sound, making increasing noise from shipping, sonar, construction, and seismic exploration an important conservation concern.
| National Research Council | National Academies / NCBI Bookshelf | 2003
Ocean noise comes from natural processes, marine animals, ships, sonar, seismic exploration, and other sources, creating a complex acoustic environment for marine mammals.
| National Research Council | National Academies / NCBI Bookshelf | 2003
Scientific evidence shows that intense or persistent human-generated sound can alter marine-mammal hearing, vocal behavior, movement, and potentially long-term fitness.
| National Research Council | National Academies / NCBI Bookshelf | 2003
A broad assessment of ocean noise explains why long-term increases in anthropogenic sound deserve continued research and conservation attention.
| Friedlaender Lab | UC Santa Cruz | n.d.
Biotelemetry researchers use animal-borne sensors to reveal whale feeding behavior, movement, population dynamics, and responses to anthropogenic sound.
Strandings and Mortality
| Anna Sophie Kebke et al. | Frontiers in Marine Science | 2026-08-21
Stable-isotope analysis of tissues from long-finned pilot whales reconstructs feeding ecology before a mass stranding in Scotland.
| Stephin Thomas | Mongabay | 2026-08-06
A blue whale calf stranding in Mumbai illustrates the logistical and scientific challenges of responding to rare cetacean deaths in India.
| David Brown | Mongabay | 2026-07-16
High gray-whale mortality along the Pacific coast is raising concern about another major population decline.
| Frederick Toro et al. | Frontiers in Marine Science | 2026-06-03
Spatial analysis of marine-otter deaths in Chile identifies patterns that can help distinguish human-related mortality risks.
| Josephine M. Slaathaug et al. | Frontiers in Marine Science | 2026-04-13
Gray whales using San Francisco Bay experienced unusually high mortality and showed limited links to known feeding groups.
| Paul Arnold | Phys.org | 2026-03-11
Observations from Patagonia suggest killer-whale pursuit can help trigger common-dolphin mass strandings.
| Kristin K. Brightwell et al. | Journal of Wildlife Management | 2025-02-10
Retrofitting Florida water-control structures with manatee protection systems was evaluated as a way to reduce human-caused manatee deaths.
| Spoorthy Raman | Mongabay | 2023-08-18
Projected increases in shipping associated with LNG development could raise collision and noise risks for whales on Canada's Pacific coast.
| Shreya Dasgupta | Mongabay | 2022-03-31
Scientists argue that naturally decomposing whale carcasses can provide valuable nutrients and habitat instead of always being removed.
| NOAA Fisheries | NOAA Fisheries | n.d.
NOAA summarizes conservation programs involving strandings, mortality investigations, monitoring, take reduction, permits, and responsible marine-mammal viewing.
Conservation, Policy, and Population Status
| Holly Crystal Raudino et al. | Frontiers in Marine Science | 2026-07
Research assesses dugong abundance and population status in Shark Bay using contemporary survey methods and Sea Country knowledge.
| W. Chris Oosthuizen et al. | Frontiers in Marine Science | 2026-07
New abundance estimates improve understanding of Indian Ocean humpback dolphins along South Africa's Garden Route.
| Thomas A. Jefferson et al. | Frontiers in Marine Science | 2026-06-26
Researchers assess the status of Hong Kong's Indo-Pacific humpback dolphins in the context of the larger Pearl River Estuary population.
| NOAA Fisheries | NOAA Fisheries | 2026
An overview of marine-mammal conservation explains U.S. protections for whales, dolphins, porpoises, seals, sea lions, walruses, manatees, sea otters, and polar bears.
| Authors listed in article | Journal for Nature Conservation | 2026
A global assessment of manatees and dugongs maintained in managed facilities examines how ex-situ populations might contribute to sirenian research and conservation.
| Marine Mammal Commission | Marine Mammal Commission | 2026
A consolidated status table identifies U.S. and international marine-mammal populations considered endangered, threatened, depleted, or otherwise at risk.
| UC Santa Cruz | UC Santa Cruz | 2025-06
Tracking data from hundreds of scientists identified important global habitats for whales, seals, sharks, turtles, and other mobile marine megafauna.
| Authors listed in chapter | Sea Otter Conservation II | 2025
Comparisons across North American populations explore why some sea-otter populations recover rapidly while others stabilize or decline.
| Authors listed in chapter | Sea Otter Conservation II | 2025
Sea-otter recovery depends strongly on individual movement, local food availability, population density, and the spatial arrangement of suitable coastal habitat.
| Thomas Dallison et al. | Ocean Governance / Marine Policy | 2025
A management self-assessment tool is evaluated for improving marine-mammal conservation within area-based conservation measures.
| Mongabay | Mongabay | 2024-12
Iceland issued multi-year permits allowing continued commercial hunting of fin and minke whales, renewing debate over modern whaling.
| Elysha Iversen, Luke E. Painter and Nicole Duplaix | IUCN Otter Specialist Group Bulletin | 2024
Researchers examine ecological, social, and management questions surrounding the possible reintroduction of sea otters to the Oregon coast.
| Dana Wright | Mongabay | 2023-04-25
Scientists describe the technological and logistical challenges of studying extremely rare North Pacific right whales.
| Authors listed in article | Frontiers in Marine Science | 2022
A comparative review examines how effectively marine protected areas protect whales, dolphins, seals, and other marine mammals and identifies lessons for future reserves.
| IUCN Marine Mammal Protected Areas Task Force | Marine Mammal Protected Areas Task Force | n.d.
Kenya's Kisite-Shimoni region supports resident Indo-Pacific bottlenose dolphins, endangered Indian Ocean humpback dolphins, migrating humpback whales, and occasional dugongs.
| IUCN Marine Mammal Protected Areas Task Force | Marine Mammal Protected Areas Task Force | n.d.
The Main Hawaiian Archipelago supports an unusually diverse community of resident and migratory whales and dolphins as well as endangered Hawaiian monk seals.
Monitoring, Technology, and Research Methods
| University of Hawaiʻi at Mānoa | University of Hawaiʻi News | 2026-08-02
Researchers are using drones to place suction-cup tags on humpback whales, reducing the need for close boat approaches.
| Florida Atlantic University | EurekAlert! | 2026-07-31
Passive acoustic monitoring of bottlenose dolphins identifies coastal areas heavily used for feeding and social activity.
| Kyoto University | Phys.org | 2026-07-14
Underwater microphones reveal regular visits by small dolphins to two coastal bays in the Sea of Japan.
| UH News | University of Hawaiʻi | 2026-07-06
Drone measurements show unusually few calves in Hawaiʻi Island's spinner-dolphin population, raising concerns about long-term viability.
| James D. Karimi et al. | Frontiers in Marine Science | 2026-07-06
Habitat models map environmentally suitable areas for eight cetacean species across the Mediterranean Sea.
| PLOS | EurekAlert! | 2026-06-24
Four decades of sightings show Bigg's killer whales increasing in Washington waters while Southern Residents have changed their seasonal presence.
| Armin Rose et al. | Frontiers in Marine Science | 2026-06-22
Twelve years of acoustic monitoring show increasing seasonal harbor-porpoise detections in Pomeranian Bay.
| Andrew John Willson et al. | Frontiers in Marine Science | 2026-06-19
Satellite tags reveal how endangered Arabian Sea humpback whales use coastal and offshore habitats across seasons.
| Florida Atlantic University | Phys.org | 2026-06-15
Scientists created a detailed 3D digital archive of a vaquita skeleton as the species remains at extreme risk of extinction.
| UH News | University of Hawaiʻi | 2026-06-05
Drone measurements reveal serious fluctuations in body condition among Hawaiʻi's endangered false killer whales.
| Peter L. Tyack et al. | Frontiers in Marine Science | 2026-06-01
Decades of Sarasota bottlenose-dolphin research helped develop and validate modern animal-borne tagging technology.
| Selene Fregosi et al. | Frontiers in Marine Science | 2026-05-19
Repeated seawater sampling can estimate genetic diversity in abundant oceanic dolphin populations using environmental DNA.
| University of Washington School of Aquatic and Fishery Sciences | UW SAFS | 2026-05-15
UW researchers analyzed more than 1,700 Cook Inlet beluga calls to connect vocal patterns with behavior and improve conservation monitoring.
| UC Santa Cruz | UC Santa Cruz | 2026-02
Six decades of elephant-seal research at Año Nuevo have produced one of the world's longest-running datasets on an individual marine mammal population.
| NOAA Fisheries | NOAA Fisheries | 2026
Long-term underwater acoustic recorders allow researchers to monitor whales, seals, and walruses across remote Alaskan waters throughout the year.
| Marine Mammals Management Toolkit | Ocean Governance | 2026
Guidance explains why effective marine-mammal monitoring in protected areas requires dedicated expertise, funding, equipment, and long-term partnerships.
| Angela R. Szesciorka et al. | Scientific Reports | 2025-11-28
Year-round acoustic detections southwest of Svalbard suggest fin whales use the region for both feeding and reproductive activity.
| Danah I. Alagha et al. | Frontiers in Marine Science | 2025-10-14
Drone surveys documented exceptionally large aggregations of dugongs in Qatar, demonstrating the importance of Arabian Gulf seagrass habitats to this vulnerable marine mammal.
| Authors listed in article | Remote Sensing in Ecology and Conservation | 2025-06-23
Drone photogrammetry was used across the Indo-Pacific to measure dugong body condition and investigate environmental and human factors affecting their health.
| Authors listed in article | Ecological Indicators | 2025-02
Research found that even relatively sparse seagrass meadows can be important dugong habitat and developed a rapid drone-based method for identifying such areas.
| Authors listed in article | Journal for Nature Conservation | 2025
Drone surveys in Qatar documented dugong population structure, calves, social organization, and probable twins, strengthening the case for transboundary Arabian Gulf conservation.
| Joseph M. Eisaguirre et al. | U.S. Geological Survey | 2024-06-25
Long-term monitoring documents the remarkable recovery and expansion of sea otters in Southeast Alaska while examining ecological factors influencing population change.
| Hiroyuki Ozawa et al. | Scientific Reports | 2024-04-04
Fecal DNA and sighting records provided evidence of dugongs in parts of Japan's Ryukyu Islands where the species had been feared locally extinct.
| Carola Chicco et al. | Marine Mammal Science | 2024
Passive acoustic monitoring revealed that humpback whales occur in southern Icelandic waters during considerably more of the year than visual observations alone suggested.
| Authors listed in article | Environmental DNA | 2024
Environmental DNA was used to monitor whales, dolphins, porpoises, and their prey within a Scottish marine protected area.
| Elizabeth Claire Alberts | Mongabay | 2022-05-09
Acoustic monitoring documented previously undescribed gunshot-like calls from humpback whales near a South Atlantic seamount.
| Mike Gaworecki | Mongabay | 2022-02-23
Bioacoustic research provides the first detailed characterization of African manatee vocalizations and demonstrates a new monitoring tool.
| Cédric Gervaise et al. | Applied Acoustics | 2021
Researchers evaluated how passive acoustic systems can be optimized to detect and locate endangered North Atlantic right whales in busy shipping areas.
| MBARI | Monterey Bay Aquarium Research Institute | 2019-06-01
An MBARI research expedition combined environmental DNA, acoustics, and autonomous vehicles while encountering humpbacks, Pacific white-sided dolphins, and northern right-whale dolphins.
| Steffen De Vreese et al. | Scientific Reports | 2018-11-15
Passive acoustic monitoring documented marine mammals in the Greenland and Barents Seas and showed the value of year-round listening in rapidly changing Arctic waters.
| Authors listed in article | Conservation Biology | 2016
Historical evidence and spatial modeling were used to estimate how numerous North Atlantic right whales may have been before centuries of commercial whaling.
| Ursula K. Verfuss et al. | Environmental Monitoring and Assessment | 2016
Experience from European offshore wind farms provides lessons about monitoring and reducing construction-noise impacts on marine mammals.
| Woods Hole Oceanographic Institution | WHOI Marine Mammal Center | n.d.
WHOI research uses tags, acoustics, medical imaging, robotics, and other technologies to investigate marine-mammal health, behavior, diving, disturbance, and conservation.
| Daniel Costa Laboratory | UC Santa Cruz | n.d.
Biologging studies of seals, sea lions, whales, and other marine predators reveal migration corridors, feeding areas, energetics, and links between animal behavior and ocean conditions.
| Woods Hole Oceanographic Institution | WHOI Marine Mammal Center | n.d.
Marine-mammal conservation increasingly combines physiology, acoustics, robotics, tagging, health assessment, and ecosystem science to understand threats that cannot be observed from the surface alone.
Behavior, Ecology, and Communication
| Smithsonian Magazine staff | Smithsonian Magazine | 2026-08-14
Long-term observations from the Golden Gate Bridge revealed rarely documented harbor-porpoise mating behavior.
| University of the Sunshine Coast | Phys.org | 2026-08
Observations in Queensland show bottlenose dolphins using shells as tools to trap fish, with possible mother-to-calf cultural transmission.
| Frontiers | ScienceDaily | 2026-07-23
Orcas in the Gulf of California were filmed using coordinated ramming to break apart large sunfish.
| Paul Arnold | Phys.org | 2026-06-16
Female bottlenose dolphins appear able to recognize and avoid troublesome males by listening for individual signature whistles.
| Sarah Kuta | Smithsonian Magazine | 2026-06-12
Deep-sea exploration uncovered a large concentration of whale remains that has supported specialized scavenger communities over millions of years.
| Rose Hilmo and William S. D. Wilcock | Frontiers in Marine Science | 2026-05-29
Ocean-bottom seismometers recorded blue-whale song and revealed late-season distributions of singing males in the northeast Pacific.
| Authors listed in article | Frontiers in Marine Science | 2026-05-11
Researchers describe newly recognized signals in the expanding vocal repertoire of East Indian Ocean pygmy blue whales.
| NOAA Fisheries | NOAA Fisheries | 2026-04-09
Research on humpback whale migration, feeding ecology, genetics, and identification helps scientists evaluate population recovery and emerging threats.
| University of British Columbia | Phys.org | 2026-03-18
Tracked ringed seals sometimes enter higher-risk polar-bear habitat when prey diversity makes the feeding opportunity worthwhile.
| Woods Hole Oceanographic Institution | WHOI | 2026-02-10
Researchers discovered what may be the oldest preserved recording of a whale, a humpback song recorded near Bermuda in 1949.
| Nathan Angelakis | Phys.org / The Conversation | 2026-02-10
Animal-borne video captured an Australian sea-lion mother taking her pup on a lengthy foraging trip, suggesting prolonged learning opportunities.
| NOAA Fisheries | NOAA Fisheries | 2026
NOAA's Marine Mammal Laboratory studies abundance, ecology, migration, population dynamics, and behavior of whales, porpoises, seals, sea lions, and fur seals.
| NOAA Fisheries | NOAA Fisheries | 2026
Recordings and spectrograms illustrate the remarkable diversity of whale, dolphin, porpoise, and pinniped sounds used for communication and navigation.
| Leah Nguyen et al. | JASCO / Aquatic Conservation | 2026
An international blue-whale research workshop identified major knowledge gaps involving population ecology, prey, distribution, behavior, and resilience to human pressures.
| Marine Mammals Management Toolkit | Ocean Governance | 2026
Baseline data on species abundance, distribution, habitat, and threats are presented as essential to effective marine protected-area management.
| Holly E. L. Gamblin et al. | Oikos | 2025-10-28
Polar bears leave substantial amounts of marine-mammal carrion available to scavengers, suggesting their ecological importance extends well beyond their role as predators.
| Joshua G. Smith et al. | Science Advances | 2025-04-30
Sea otters responded to major changes in rocky-shore prey populations, revealing complex ecological interactions involving multiple keystone predators.
| IUCN Marine Mammal Protected Areas Task Force | Marine Mammal Protected Areas Task Force | 2025
Hundreds of Important Marine Mammal Areas have now been identified worldwide based on population vulnerability, distribution, feeding, migration, reproduction, and other ecological criteria.
| Authors listed in article | Nature Communications | 2025
Migrating baleen whales move large quantities of nitrogen and other nutrients from productive feeding areas toward tropical breeding grounds.
| Rikke Jeppesen et al. | Biological Invasions | 2024-12-10
Recovering southern sea otters in California's Elkhorn Slough suppress invasive European green crabs, demonstrating a valuable ecosystem effect of predator recovery.
| Elizabeth Claire Alberts | Mongabay | 2023-01-25
Debate over emergency protections illustrates the difficulty of balancing fisheries with the urgent needs of North Atlantic right whales.
| Elizabeth Claire Alberts | Mongabay | 2022-12-20
Research suggests extinct Steller's sea cows once reshaped kelp ecosystems through grazing, leaving an ecological legacy after their disappearance.
| Mike Gaworecki | Mongabay | 2022-06-15
Bioacoustic studies revealed unusual humpback calls in the South Atlantic and bottlenose-dolphin behavior in New York Harbor.
| Grace Hansen | Mongabay | 2022-06-07
Experimental evidence suggests some whales respond to human-generated noise in ways resembling anti-predator behavior.
| Olga Koubrak, David L. VanderZwaag and Boris Worm | Ocean & Coastal Management | 2021-02-01
North Atlantic right-whale conservation in Canada illustrates how climate-driven shifts in whale distribution can require rapidly changing fisheries and shipping policy.
| Authors listed in article | Ecology and Evolution | 2018
Genetic and photo-identification data were combined to study movement and connectivity of bottlenose dolphins among marine protected areas in western Ireland.
| Scott Veirs, Val Veirs and Jason D. Wood | PeerJ | 2016
Measurements showed that commercial shipping produces noise at frequencies used by endangered southern resident killer whales for communication and echolocation.
| Authors listed in article | PLOS ONE | 2015
Vessel interactions caused common dolphins in New Zealand to spend less time foraging and delayed their return to normal feeding behavior.
| L. W. Lefebvre et al. | Pacific Conservation Biology / USGS | 2000
Research comparing Florida and Puerto Rico examines how manatees use seagrass habitats and how grazing ecology can inform conservation management.
| NOAA Fisheries | NOAA Integrated Ecosystem Assessment | n.d.
Marine mammals serve as major predators and ecosystem indicators in the California Current, where their distributions respond to environmental variability and human pressures.
| Pinniped Cognition and Sensory Systems Laboratory | UC Santa Cruz | n.d.
Research on seals, sea lions, and walruses explores hearing, cognition, vocal learning, sensory biology, and adaptations to aquatic environments.
Physiology, Genetics, and Evolution
| Michelle N. Hartwick et al. | Frontiers in Marine Science | 2026-08
Body-condition patterns in Arctic seals vary with season and development, providing a baseline for evaluating environmental stress.
| Travis Park | Nature Reviews Biodiversity | 2026-07-14
A review traces cetacean evolution from terrestrial ancestors to the extraordinary ecological and anatomical diversity of modern whales and dolphins.
| Angela L. Sremba et al. | Frontiers in Marine Science | 2026-07-10
Gene-expression comparisons among gray, humpback, and fin whales offer new tools for studying cetacean physiology and environmental responses.
| Virginia Gewin | Nature | 2026-05-27
Researchers are extracting hormone histories from baleen, whiskers, and tusks to reconstruct pregnancy, stress, and life-history events in marine mammals.
| Frontiers | Phys.org | 2026-04-30
Australian fur seals rapidly increase heart rate at the surface after dives, helping clear metabolic byproducts accumulated during foraging.
| Theresa-Anne M. Tatom-Naecker et al. | Frontiers in Marine Science | 2026-04-21
Fatty-acid signature analysis is tested as a new method for estimating the diets of free-ranging bottlenose dolphins.
| UH News | University of Hawaiʻi | 2025-11-13
Energetic modeling estimates the daily prey requirements of Hawaiʻi's deep-diving short-finned pilot whales.
| Lennart Schreiber et al. | Nature Communications | 2025-05-15
Sedimentary ancient DNA reconstructs 12,000 years of marine-mammal distribution shifts around northern Greenland.
| Madonna L. Moss et al. | Royal Society Open Science | 2025-01
Stable-isotope evidence from archaeological and modern sea otters helps reconstruct the species' historical ecology and may inform future recolonization efforts.
| Authors listed in article | Nature | 2025
Cellular experiments indicate unusually effective DNA repair may contribute to the bowhead whale's exceptional longevity.
| Janet M. Lanyon et al. | Marine Mammal Science | 2024-10-04
Researchers directly measured the metabolic requirements of wild dugongs to estimate how much seagrass these large marine herbivores need.
| UC Santa Cruz | Marine Mammal Physiology Project | n.d.
Experimental physiology research investigates how whales, dolphins, seals, sea lions, and sea otters expend energy and cope with environmental challenges.
| Terrie Williams Laboratory | UC Santa Cruz | n.d.
Comparative research investigates diving physiology and the behavioral and physiological effects of human disturbance on dolphins, narwhals, seals, and sea otters.
Tourism and Human–Marine Mammal Interactions
| Kim Bassos-Hull et al. | Frontiers in Marine Science | 2026-08
Researchers evaluated how two bottlenose dolphins behaved after being returned to the wild following two years in managed care.
| Brookfield Zoo Chicago | Phys.org | 2026-05-28
Human-associated feeding behavior has reshaped social connections among bottlenose dolphins in Sarasota Bay over decades.
| Douglas Clark | Phys.org / The Conversation | 2026-05-01
Camera monitoring shows that polar-bear visits to human infrastructure reflect more than simple hunger and may involve curiosity and local conditions.
| Mongabay | Mongabay | 2025-12
Rapidly growing swim-with-whale tourism in Timor-Leste raises concerns about disturbance along an important cetacean migration corridor.
| Changsoo Kim et al. | Scientific Reports | 2025-07-18
Surveillance technology was used to monitor interactions between wild dolphins and a dolphin undergoing rehabilitation.
| Jinyan Chen et al. | Asia Pacific Journal of Tourism Research | 2024-09-09
Public perceptions of dolphins in tourism reveal tensions among entertainment, education, conservation, and animal welfare.
| Jinyan Chen et al. | Hong Kong Polytechnic University | 2024
Analysis of social-media discussions explores public attitudes toward wild dolphin tourism and dolphin attractions and the ethical questions surrounding both.
| Authors listed in article | Frontiers in Marine Science | 2021
Citizen scientists, tourism operators, fishers, and researchers have helped build knowledge of whales and dolphins along Kenya's poorly studied Indian Ocean coastline.
| A. Cecchetti et al. | Journal of the Marine Biological Association of the UK | 2017
Researchers studied how whale-watching vessels alter the short-term behavior of common dolphins in the Azores.
| Leslie F. New et al. | Ocean & Coastal Management | 2015-10
A review examines how repeated whale-watching disturbance may translate from short-term behavioral effects into population-level consequences.
| Michael Lück | Ocean & Coastal Management | 2015-01
Surveys of whale- and dolphin-watching tourists in New Zealand investigated what visitors want to learn and how wildlife tourism can contribute to education.
