Sea Otters Face New Deadly Threat, and Humans Can Catch It, Too
Matthew Russell
Sea otters, the smallest marine mammals in North America, are iconic symbols of the California coast and a keystone species. These furry creatures once numbered in the hundreds of thousands, but due to hunting, habitat loss, and pollution, they have become one of the most endangered marine mammals in the world. In recent years, a new threat has emerged that could drive otters to extinction: a bacterial infection known as toxoplasmosis.
Photo: Adobe Stock / erikakirkySea otters are a marine mammal found along the coasts of the Pacific Ocean.
The Bacterial Threat
Toxoplasmosis is caused by the parasite Toxoplasma gondii, which can infect a wide range of mammals, including humans. The parasite can be found in the feces of infected cats, and it can survive in the environment for months, even years. Sea otters are particularly vulnerable to toxoplasmosis because they can become infected by ingesting contaminated water or prey, such as shellfish or crabs.
Toxoplasmosis is not the only threat facing sea otters. Another major threat comes from bacterial infections, which can cause severe illness and death in these animals. The most common bacterial infection found in sea otters is caused by the bacterium Streptococcus, which can infect the lungs, liver, and other organs. Streptococcus infections can be fatal for sea otters, and outbreaks of the disease have been responsible for significant declines in sea otter populations in the past.
Photo: In addition to Streptococcus, sea otters are also vulnerable to other bacterial infections. One such infection is caused by the bacterium Vibrio, which can be found in coastal waters and can infect sea otters through open wounds or ingestion of contaminated water or prey.
Another bacterial infection that can affect sea otters is caused by the bacterium Leptospira, which is found in the urine of infected animals and can be transmitted through water or contaminated soil, reports the Centers for Disease Control and Prevention. To protect sea otters from these bacterial threats, researchers and conservationists are working to better understand the risk factors associated with these infections and to develop effective prevention and treatment strategies.
Making matters worse for these small, furry mammals:
- Sea otters are particularly susceptible to bacterial infections because they have a weaker immune system compared to other marine mammals.
- Bacterial infections are not only a threat to wild sea otters, but also to otters in captivity, where they can spread rapidly and cause significant mortality.
- In addition to bacterial infections, sea otters are also vulnerable to viral infections such as the herpes virus, which can cause severe disease and death in these animals.
Photo: Potential Health Risks of Toxoplasmosis
Toxoplasmosis can have serious consequences for sea otters. Studies show infection can lead to neurological problems, blindness, and even death. Another study conducted by the University of California, Davis, found that toxoplasmosis was responsible for the deaths of nearly 40% of the southern sea otters that were necropsied between 1998 and 2004.
Humans can also be at risk of infection from Toxoplasma gondii, the CDC reports. While healthy individuals may experience flu-like symptoms, the infection can be more severe in people with weakened immune systems, such as those with HIV or cancer.
Photo: Adobe Stock / David A LitmanToxoplasmosis can cause severe illness in sea otters, including death.
Threats to Otters
Habitat loss is a major threat to sea otters, as human activities such as coastal development, oil spills, and commercial fishing have damaged or destroyed large areas of the otters' natural habitat, SeaOtters.com reports. Pollution is another significant threat, as pollutants such as oil, pesticides, and heavy metals can accumulate in otters' bodies and disrupt their immune systems, studies show. Climate change also poses a threat to sea otters, the NRDC reports, as rising temperatures and ocean acidification can affect the availability of the otters' prey and disrupt their reproductive cycles.
Toxoplasmosis adds another layer of danger to an already precarious situation. When sea otters consume contaminated food or water, they can become infected with T. gondii, USA TODAY reports, which can cause severe illness or death. Studies show toxoplasmosis has been identified as a leading cause of death in sea otters in Southern California. The parasite can also affect the reproductive success of sea otters, as infected females may experience stillbirths or abortions.
Photo: Adobe Stock / Africa StudioToxoplasmosis can be transmitted through cat feces into water streams.
In addition to toxoplasmosis, sea otters face other threats that could drive them to extinction, including:
- Overfishing: Overfishing can deplete the otters' food sources and lead to starvation.
- Entanglement in fishing gear: Sea otters can become entangled in fishing gear such as nets and traps, which can cause injury or death.
- Disease: In addition to toxoplasmosis, sea otters are vulnerable to other diseases such as canine distemper virus and avian influenza.
- Predation: Sea otters may be preyed upon by sharks, killer whales, and other predators.
Photo: Humans and Toxoplasmosis
The impact of human activity on the spread of toxoplasmosis among sea otters cannot be ignored. The National Oceanic and Atmospheric Administration (NOAA) identifies land-based sources of pollution, particularly from urban and agricultural runoff, as a significant threat to the marine environment. When it rains, water runs off into streams, rivers, and eventually the ocean, carrying with it a range of pollutants, including cat feces contaminated with T. gondii.
In addition to runoff, human activities such as beach closures and coastal development can also impact sea otter populations. Beach closures due to bacterial contamination can reduce the availability of food for sea otters, leading to malnourishment and weakened immune systems. Coastal development can also lead to habitat loss and degradation, as well as increased pollution from runoff and other sources. The loss of habitat and food sources can further make sea otters more susceptible to disease, including toxoplasmosis.
Photo: Reducing the Risk of Transmission
To reduce the risk of transmission of toxoplasmosis, it is essential to properly dispose of cat feces. Cat owners should always dispose of litter in the trash, and outdoor cats should be kept in a litter box or on a leash. In addition, beachgoers can help by following beach closure notices and avoiding areas where sea otters are present, as well as minimizing disturbance to sea otters and other marine mammals in their natural habitats.
Toxoplasmosis is not the only threat to sea otters, but it is one that can be controlled. By taking simple steps to reduce the risk of transmission, we can help protect these charismatic creatures and ensure that they continue to thrive in our coastal waters.
Photo: The Importance of Sea Otters
Sea otters play an important role in the marine ecosystem. According to Defenders of Wildlife, they are a keystone species, meaning that their presence or absence can have a significant impact on the overall health of the ecosystem. Sea otters feed on sea urchins, which are herbivores that graze on kelp. When sea otters are present, they keep sea urchin populations in check, allowing kelp forests to thrive, reports Sea Otter Savvy. Kelp forests provide habitat for a wide range of marine life, including fish, invertebrates, and birds.
Sea otters are not only important for their role in maintaining the health of the marine ecosystem, but also for their ability to act as an indicator species for environmental health. They are particularly sensitive to changes in water quality, habitat loss, and other environmental stressors.
In addition to their ecological importance, sea otters also have cultural and economic significance. They have been a part of the cultural history of indigenous communities in Alaska and the Pacific Northwest for thousands of years, reports a study in American Antiquity. They also draw tourists and recreational visitors to coastal areas, contributing to local economies.
Photo: Hope for Otters
With bacterial infections posing a significant threat to the survival of sea otters, it is crucial that we take steps to protect them. Sea otters are not only important for the balance of the ecosystem, but they are also valuable to humans as an indicator of the health of the ocean. The risk of transmission of these infections to humans cannot be overlooked, and it is important that we take steps to protect ourselves as well.
Protecting sea otters requires a concerted effort from all of us. We must work to reduce the use of antibiotics in agriculture and other industries to reduce the prevalence of antibiotic-resistant bacteria in the environment. We must also take steps to reduce our impact on the environment by reducing pollution and protecting the coastal habitats where sea otters live. In addition, we must support research to better understand the causes and effects of bacterial infections in sea otters. This research can help us to develop new treatments and strategies for protecting sea otters and other marine animals.
You have the power to make a difference in protecting these vulnerable animals and their habitats, too. By taking the Otter Protection Pledge, you can take concrete steps to reduce your impact on the environment and reduce the spread of toxoplasmosis.
Through our collective actions, we can help ensure that sea otters continue to thrive for generations to come. Click below and save sea otters!
