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Human remains decompose in B.C. waters in less than four days: study

The Simon Fraser University study's findings could be beneficial for investigators and recovery divers searching for bodies submerged in the Strait of Georgia.

The Simon Fraser University researchers used pig carcasses because they are roughly the size of a human torso, have no hair and their guts have similar bacteria as humans.

Contributed

The Simon Fraser University researchers used pig carcasses because they are roughly the size of a human torso, have no hair and their guts have similar bacteria as humans.

Human remains lost in deep waters off the B.C. coast decompose at a much faster rate than previously thought, suggests a new Simon Fraser University study.

The findings could be beneficial for investigators and recovery divers searching for bodies submerged in the waters of the Strait of Georgia, said SFU criminologist Gail Anderson, who led the study, which is the first to investigate what happens to bodies when they are submerged in the sea.

 “We’ve been looking at carcass decomposition in various environments in both spring and fall,” Anderson told Metro. “But what we found this time was very, very different from previous work we’ve done in Saanich Inlet and in Howe Sound.”

Simon Fraser University criminologist Gail Anderson is leading a study investigating what happens to bodies when they are submerged in the sea.

Marianne Meadahl/Simon Fraser University

Simon Fraser University criminologist Gail Anderson is leading a study investigating what happens to bodies when they are submerged in the sea.

Deploying four pig carcasses at a depth of 300 metres into the waters of the Strait of Georgia— two in spring and two the next fall — the researchers placed live cameras and sensors in front of the carcasses to record factors like oxygen, temperature, salinity, density and pressure every minute.

The researchers used pig carcasses because they are roughly the size of a human torso, have no hair and their guts have similar bacteria as humans.

Working with the Victoria Experimental Network Under the Sea, or VENUS, a cabled underwater laboratory, the researchers found the pig carcasses were reduced to skeletons in less than four days.

Immediately after they were submerged, the researchers noticed that the carcasses were quickly covered in vast amounts of small shrimp-like creatures called lyssianassid amphipods.

In fall, the carcasses were reduced to skeletons within three days, while in spring, the process took four days.

Anderson said she wasn’t surprised by the findings.

“Working and speaking with colleagues of mine who are recovery divers with the RCMP, that’s what they say they get: areas of the body that are exposed are skeletonized very quickly by the amphipods,” she said. “This was the first time we actually saw it the way they’ve described it from the bodies they’ve recovered from these areas.”

Vast amounts of small shrimp-like creatures called lyssianassid amphipods covered the pig carcasses immediately after they were submerged, reducing them to skeletons within four days.

Contributed

Vast amounts of small shrimp-like creatures called lyssianassid amphipods covered the pig carcasses immediately after they were submerged, reducing them to skeletons within four days.

Previous studies by Anderson and SFU colleague Lynne Bell looking at decomposition at depths of between seven and 15 metres and 100 metres found that a carcass could remain in tact for weeks or months, depending on oxygen levels, temperature, depth and whether it remained in contact with the seabed.

Through that research, Anderson said she helped investigators solve the "mystery" of some of the 14 disembodied feet that have washed up on the West Coast over the past decade by showing that the feet were not severed, but rather were naturally "scavenged" by marine creatures. 

Anderson said she and her colleagues are now taking their experiment to even deeper waters.

She said the study’s findings provide recovery divers with a realistic idea of what to search for, and can help investigators determine where and how long a body was in the water.

The findings can also help prepare family members for what to expect if remains are found, she said.

“If somebody has gone into the water and they’ve been missing for 24 hours or four days, are they going to recover a body or just bones?” she said. “Depending on the type of water they’re in, that’s going to be very different.”

The study was recently published in PLoS One.