Peter Mieras of Rendezvous Dive Adventures in Rainy Bay is a diver, a filmmaker and citizen scientist who has run a sixgill shark survey project for almost a decade. On Feb. 7 he was invited to document a necropsy done on a sixgill shark that had washed up on a beach near Saanich earlier that week.
A necropsy is like an autopsy on an animal; the examination of an animal carcass after death.
“I was very excited to be invited to document the necropsy done by DFO (Fisheries and Oceans Canada) and UVic last Thursday,” Mieras said.
He arrived at Coles Bay beach early Thursday morning and was dismayed to discover the shark’s head had been chopped off and the rest of the carcass left in the water. “I was shocked that someone had stolen the head and jaw the evening before,” he said.
“Not only is this shark a species listed under SARA ( Species at Risk Act) and taking parts without permission is illegal, but it also deprived many of the interested individuals from the general public a chance to fully appreciate this animal. And of course the loss of information that might have been obtained.”
Because Mieras arrived at the beach two hours before the team of scientists did, he became an impromptu shark educator for the steady stream of onlookers. “The majority of interested people were parents with children and I really enjoyed giving them a basic idea of shark anatomy, biology and behaviour for this species,” Mieras said.
“One of the things that interested many, was the skin of the shark. It has scale-like teeth over its surface. This helps the water flow easier past the skin, thus making swimming for the shark more efficient—much like a golf ball has dimples that helps it fly better through the air. So when you run your hand over the skin from tail to head it is rough like sandpaper. When you run in the same direction as the water runs when the shark swims its skin is very smooth.”
Many of the lab people who showed up were former divers and some have participated in Mieras’ shark survey week in Barkley Sound.
Once the necropsy began, “a stringent protocol was followed and muscle samples, fin clippings, organs and other tissues were secured for further analysis,” he explained. “In total 73 pups were extracted from the 13-foot female and measured and taken back for genealogy research. The pups were also shown to the crowd and many exclamations of ‘OMG so cute’ were heard, which generally are not elicited when talking about sharks.”
The record number of pups born for sixgill sharks is 116, Mieras said. He didn’t know whether the sixgill shark that washed up on the beach at Coles Bay had already delivered any pups. “It is hard to say (whether) some pups made it out.”
He said according to other shark experts, sepsis and complications during birth is not uncommon. “These sharks develop eggs in the uterus into miniature sharks who are then born live (called aplacental viviparity). So quite an invasive event.”
This isn’t the first time a dead sixgill shark with pups has washed up on a Vancouver Island beach. In 2011 a Port Alberni log salvager discovered the carcass of a 12– to 14–foot sixgill on a beach near the former Coulson Sawmill (now San Group’s sawmill) west of Port Alberni on the Alberni Inlet. Five dead pups slipped out of the shark as it was winched up from the beach.
There are at least a dozen shark species that have been spotted in Barkley Sound.
Common species according to a biologist with Pacific Rim National Park Reserve include blue shark, blunt nosed six gill, broad nosed seven gill, great white shark, salmon shark, spiny dogfish and the tope shark.
Less common are the brown cat shark, and other deep water species such as the; Pacific angel shark, Pacific sleeper shark, short-finned maco shark and thin tailed thresher shark.
Mieras expects necropsy results from the Coles Bay sixgill shark will be released later this week. He plans to create a short video of his experience in the next month and will post it on his YouTube channel, www.youtube.com/user/rendezvousdiving.