Encountering a seal carcass along a coastline is a normal and natural part of the marine ecosystem. These events represent the conclusion of a life cycle and initiate ecological processes. Understanding the context of this finding can transform it from a somber sight into an appreciation for the complexities of coastal environments.
What to Do If You Find a Seal Carcass
The first action is to maintain a safe distance from the carcass; officials recommend staying at least 150 feet away. This distance protects you from potential pathogens and prevents your scent from deterring scavengers that rely on the carcass for food. It is also important to keep pets, especially dogs, leashed and far away from the remains.
Do not touch or attempt to move the seal carcass. Seals are protected under federal laws like the Marine Mammal Protection Act, which makes tampering with, moving, or collecting parts from the carcass illegal. Handling the animal also poses a direct health risk, as seals can carry bacteria and viruses transmissible to humans.
The most helpful action you can take is to report your finding to the appropriate authorities. Note the specific location, providing as much detail as possible, such as nearby landmarks or beach access numbers. From a distance, observe the animal’s condition for any visible signs of injury or entanglement. This information should be reported to the NOAA Fisheries Marine Mammal Stranding Network hotline or a local marine wildlife agency.
Common Causes of Seal Mortality
Seal mortality is often attributed to natural causes. Infectious diseases, such as phocine distemper virus, can cause widespread illness and death within a population. Malnutrition and starvation are also common, particularly among young pups that are unable to forage successfully. Predation by animals like great white sharks and orcas is another natural cause of death.
Human activities also contribute to seal mortality. Entanglement in fishing gear, known as bycatch, is a threat where seals can get caught in nets or lines, leading to drowning or severe injury. Strikes from vessels, especially in busy shipping lanes or recreational boating areas, can cause fatal trauma.
Environmental factors linked to human presence can also be a cause. For instance, diseases like toxoplasmosis, which is lethal to seals, can be introduced into the marine environment through runoff containing cat feces. The accumulation of environmental contaminants in the food web may also impact seal health over time, contributing to their vulnerability to other stressors.
The Ecological Role of a Seal Carcass
A seal carcass that washes ashore becomes a food source, or carrion, for a wide array of scavengers. On land, birds like gulls and eagles, as well as terrestrial mammals such as coyotes or bears, will feed on the remains. This provides them with a high-energy meal that is important in lean times.
The process of decomposition is part of nutrient cycling in coastal environments. As the carcass breaks down, it releases nutrients, including nitrogen and phosphorus, back into the ecosystem. These nutrients enrich the soil on shorelines or the sediment on the seafloor, promoting the growth of plants and microorganisms.
Reporting a carcass also transforms it into a scientific opportunity. Each deceased animal provides data for researchers studying marine mammal populations. Scientists can gather information on genetics, diet, exposure to contaminants, and the prevalence of diseases. This knowledge helps managers understand the threats facing seal populations and develop more effective conservation strategies.