In most cases, the cause of stranding is unknown. Some identified causes in Virginia strandings include:
- parasite infestation
- injuries due to vessel strikes
- fishery entanglements
- ingestion of marine debris
- cold-stunning (sea turtles)
In addition, strandings sometimes occur after unusual weather or oceanographic events such as hurricanes.
Sea turtles and marine mammals are very difficult to study in the wild. Strandings provide scientific sampling opportunities and increase our understanding and interpretation of data collected from wild populations. Through necropsies, we have learned a significant amount about the basic physiology and biology, health and causes of mortalities of animals that are not accessible in the wild or through any other means. There are marine mammal species that have been identified solely from stranded specimens. Stranding data help us make better management and conservation decisions about marine mammal and sea turtle populations.
Important scientific information can be learned from examinations and necropsies (animal autopsies) of stranded animals, especially if the animal has recently died. The sooner our Stranding Response Team can respond, the more valuable the information. For example:
- pathology to investigate diseases, parasites and even injuries
- reproductive information such as sexual maturity
- life history (such as an animal's age, diet, calving history)
- contaminant levels from pollution or bio-toxins
- normal biology and physiology parameters
- evidence of human interactions such as vessel strikes, entanglements, hooks and marine debris ingestion
With the exception of 2013, which was a record year because of an unusual mortality event that affected bottlenose dolphins, we respond to 75-125 marine mammals and 200-350 sea turtles each year in Virginia. Within the NOAA National Marine Fisheries Service Northeast Region (Virginia to Maine), Virginia stranding numbers are usually within the top two or three in the region.
The Aquarium has the facilities, resources, and expertise to rehabilitate most sea turtle species that occur in Virginia (all except leatherbacks), and we regularly receive patients from outside the state. We can also rehabilitate juvenile seals which occasionally strand in the area. Although few single stranded cetaceans are strong enough for transport and rehabilitation, we can hold a small animal such as a juvenile bottlenose dolphin or harbor porpoise for up to 48 hours before transferring it to a larger facility. Larger cetaceans such as baleen whales incur severe internal damage and trauma just from being stranded. Although one's first instinct is to push a live animal back into the ocean, most animals strand because they are sick or injured and dying. Pushing an animal back often results in a second stranding and prolonged suffering. When faced with such a situation, we believe that the most humane resolution is to quickly euthanize animals that are not candidates for rehabilitation.
The answer is no. Marine mammals and sea turtles are federally protected, many are endangered and threatened species, and you must have authorization from the NOAA National Marine Fisheries Service and the U.S. Fish and Wildlife Service to handle these animals. In addition, the state of Virginia requires that you have a permit to handle endangered and threatened species. If you see a stranded sea turtle or marine mammal in Virginia, call the Aquarium Stranding Response Team (757-385-7575), the local police or U.S. Coast Guard (see Report a Stranding).