According to TV mobsters, to be “sleeping with the fishes” is the worst punishment anyone can receive. There are many reasons that human bodies end up in the ocean, but they all have one thing in common: it is not entirely clear how scavengers in the ocean deal with them. In order to investigate how this decomposition occurs, a Canadian team deposited pig bodies into the Saanich Inlet over the course of three years and monitored scavenger progress with underwater cameras. The research was conducted by Gail Anderson and criminologist Lynne Bell of Simon Fraser University, and the paper was published in PLOS ONE.
Pig carcasses were chosen for this study because they are good approximations of a human's gut microbe fauna, size, skin, and amount of body hair. In addition to studying how scavengers respond to terrestrial mammals, this research is also valuable to forensic scientists who can use the information to help solve crimes.
Three pigs were dropped into the Saanich Inlet, a body of salt water in British Columbia. They were monitored with cameras in the Victoria Experimental Network Under the Sea (VENUS) program, which provides a live feed via the internet. The first two pigs dropped were stripped down to the bone in a matter of three weeks by crustaceans.
The third pig, however, took over 90 days to be completely eaten because a lack of dissolved oxygen in the environment prevented the larger scavengers from moving in. In addition to the cameras, the pair were also able to monitor the chemistry of the water, current, and other factors that might have influenced how the body was broken down.
“Saanich Inlet is hypoxic (deficient of oxygen) most of the year and anoxic (without oxygen) at some times,” Anderson stated in a press release. “While the animals there are adapted to low oxygen, the last carcass was deployed when it was extremely low, which kept out all the big scavengers such as the shrimp and Dungeness crab, leaving the Squat lobsters, which were unable to break through the skin. This now gives us a better understanding of what happens to bodies in such waters.”
A forensically-relevant piece of information they were able to determine is that feet naturally come apart from the skeleton when being broken down. If a person who ended up in the water was wearing sneakers at the time of death, the foam soles would make the feet float on top of the water.
“So the so-called mystery of the ‘floating feet’ washing up on shores along the West Coast was not a mystery, but a natural occurrence in the marine environment,” Anderson explained.
Anderson and Bell plan to take the research further by dropping pigs into other environments even deeper into the ocean. If you’d like to see live shots from Anderson’s ongoing research with the 10th pig carcass, check out the live video feed. The lights come on every 15 minutes, starting at the top of the hour, so if you click the link and the feed looks black, be sure to check back every quarter hour for a better view. Here is a highlight reel from one pig being consumed by scavengers: