Articles tagged with Marine Mammals
A new study finds that female walruses in the Chukchi Sea rely on biomarkers from algae growing within sea ice as a primary food source. The researchers tracked these markers using liver tissues from harvested animals, revealing a difference in foraging behavior between males and females.
Researchers discovered three phases of growth that explain how cetaceans shift their nasal passage from a parallel to an angled orientation. This finding provides insight into the developmental process and could inform our understanding of cetacean evolution.
Sea otters have a higher basal metabolic rate than predicted for their size, with skeletal muscle being the primary source of this hypermetabolism. This process, known as thermogenic mitochondrial leak, allows them to maintain a normal body temperature in cold water environments.
Fossilised footprints from 58 million-year-old rocks in Wyoming reveal that early mammals used marine habitats, pushing back an estimated 9.4 million years of previous assumptions. The prints showed diverse tracks, including those of semiaquatic mammals and artiodactyls.
Researchers have proven that a sexually transmitted herpesvirus causes cancer in California sea lions, with parallels to human cervical cancer. The study suggests pollutants and viruses play a role in cancer development, making sea lions a valuable model for human cancer research.
A recent study found that viral-caused cancer in California sea lions is significantly increased by exposure to toxins in the environment. The disease has claimed 18-23% of adult sea lion deaths, highlighting the need for improved efforts to prevent ecosystem contamination with pollutants.
A new study reveals that California's coastal gillnet fisheries took a greater toll on harbor porpoises than previously thought, with the population recovering dramatically since their ban. The Morro Bay stock has rebounded by seven-fold, from an estimated 570 animals in 1991 to approximately 4,200 porpoises today.
Scientists have identified a novel skin disease in dolphins caused by climate change, with patchy and raised lesions covering up to 70% of their bodies. The study provides the first-ever case definition for freshwater skin disease in bottlenose dolphins.
A new study reveals that dolphins adjust their heart rate to suit the length of their planned dive, conserving oxygen and avoiding decompression sickness. This conscious adjustment allows them to safely dive for long periods, providing insights into marine mammal physiology.
Mercury concentrations in ringed seals from the Canadian Arctic have remained stable since 1977, with limited declines detected. Climate parameters may be influencing mercury accumulation in seals, according to a 45-year study.
A new report by the Pacific Northwest National Laboratory suggests that marine renewable energy devices are unlikely to cause harm to marine animals or environments. The study found that small numbers of operational devices may not significantly affect marine ecosystems, but further research is needed to confirm this.
A global analysis of over 300 marine species spanning more than 100 years shows that mammals, plankton, fish, plants, and seabirds are changing in abundance as oceans warm. Some marine species are benefiting from climate change, while others are declining due to warming temperatures.
A 15-year study links Arctic sea ice decline to the emergence of a deadly phocine distemper virus in northern sea otters and other marine mammals. The loss of sea ice facilitates disease transmission among species, highlighting the need for understanding PDV transmission in rapidly changing environments.
Researchers used images from tourists to study the smalleye stingray, finding individuals migrated hundreds of kilometers along the coastline. The findings highlight the need for more knowledge about this endangered species' ecology and behavior to inform conservation efforts.
A recent study found that climate change can have long-lasting negative impacts on dolphin populations, with a 12% decrease in survival rate following a heatwave in Shark Bay, Western Australia. The researchers also observed fewer births among female dolphins, which persisted for at least six years.
A study found that warmer ocean temperatures reduce maternal care and immune response in fur seal pups, leading to increased hookworm infections and deaths. In colder years, pups receive more care and have a stronger immune system.
Researchers discovered a large bone belonging to the extinct marine mammal Paleoparadoxia, which lived in Japan and the western coast of North America 23-10 million years ago. The well-preserved fossil provides valuable insights into the locomotion of hind limbs.
A coalition led by the Mexican government has developed a bold emergency plan to rescue and protect the critically endangered vaquita porpoise. The plan includes construction of a sea pen sanctuary with up to $3 million in funding, aiming to recover a population that once numbered 600 animals.
Researchers have developed a new passive acoustic monitoring method using autonomous underwater vehicles, gliders, and floats to capture sounds of marine life. The method, which was tested in the US Pacific, has the potential to provide more accurate data on marine mammal density and abundance.
A recent study found that dolphin serum contains high levels of antioxidant protein, which may hold clues to treating aging-associated diseases in humans. Researchers also discovered 11 proteins more prevalent in dolphin serum than in human samples, including vanin-1 and adiponectin.
Researchers found high levels of pesticides and contaminants in California condors near the coast compared to inland birds. The study suggests that feeding on marine mammal carcasses could complicate condor recovery due to potential harm from toxic substances.
A four-year study found substantial differences between fetal and newborn dolphins in the Gulf of Mexico affected by the Deepwater Horizon oil spill. The researchers identified lung abnormalities and small size among stranded perinatal dolphins, suggesting they died in the womb or shortly after birth due to exposure to petroleum products.
Scientists from GEOMAR found a possible reason for increasing oxygen deficiency in tropical zones, attributing it to fluctuations in trade winds. This change affects the habitat of fish species and can reverse once trade winds strengthen.
A new analysis reveals the scope of by-catch in various regions, with high rates found in the eastern Pacific, Mediterranean, southwest Atlantic, and Southern Indian oceans. The study emphasizes the importance of community engagement and data-driven approaches to mitigate by-catch, particularly in less-regulated small-scale fisheries.
Scientists have identified issues with standard toxicity testing data used to inform dispersant decisions, highlighting the need for more accurate and comparable data. The current practices do not adequately replicate field conditions, such as sea state and weather, or consider exposure durations and concentrations.
Scientists detected H1N1 virus in free-ranging northern elephant seals off California coast, indicating potential for transmission to humans. The discovery highlights the importance of protecting workers handling marine mammals and preventing disease transmission between species.
A new study reveals that white shark diets change with age, but individual sharks show surprising variability in dietary preferences. The researchers analyzed growth bands in shark vertebrae to trace variations in diet over a shark's lifetime.
A Harvard University study reveals that circumpolar rivers are the primary source of toxic mercury in the Arctic, surpassing atmospheric forces. The discovery has significant implications for protecting the health of northern populations and the environment.
A study by ecologists in New Zealand found that a 1170 km2 marine sanctuary significantly improved survival of Hector's dolphins, one of the rarest dolphin species. The research revealed a 5.4% increase in survival rates since the Marine Protected Area was designated in 1988.
Severe ill health has been found in bottlenose dolphins in Barataria Bay, Louisiana, which received heavy exposure to oil during the Deepwater Horizon spill. Preliminary results show underweight, anemic and diseased dolphins, as well as low levels of stress response hormones.
Researchers found that seal mothers adopt a wide range of mothering styles, with some being very attentive while others are not. The study also revealed large differences in response to potential dangers among both female and male seals, with no correlation to age or size.
Researchers found that adolescent great whites struggle with capturing and killing large marine mammals due to their weak jaws. However, they can maintain high bite forces using a unique jaw muscle arrangement, a trait common among successful predators.
Researchers used molecular probes to identify a toxic diatom linked to the deaths of over 400 California sea lions. The DNA probe tests detected a short but significant bloom in Pseudo-nitzschia australis, allowing researchers to connect the sea lion deaths to the bloom.
The ONR report highlights the need for further research into the effects of underwater noise on marine life, including non-hearing physiological effects and behavioral changes. The report also reviews current scientific knowledge and expert opinions on the topic, emphasizing the importance of understanding the impacts of human activiti...