Sunken ships may be interesting for divers, but are they beneficial to the environment?
That's the question Desiree Bulger, a UVic Environmental Studies masters student, has been asking of artificial reefs.
Using sonar and Remotely Operated Vehicles, Bulger surveyed the 8 ships and one plane sunk off the coast of BC, and compared the artificial habitats to the surrounding natural habitat. Her research shows that the marine life are finding uses for these sunken vessels.
"What I found overall, was that artificial reefs had more variation in the amount of fish, so sometimes there were a whole bunch of fish, sometime there weren't very many. Whereas natural reefs were more consistent, they had kind of an intermediate amount of fish, and they were kind of similar to each other, less variation"
She adds there were more threatened species inhabiting artificial reefs, including rockfish. She says this is good news, as rockfish, particularly quillback and yelloweyes, which are targeted by fisheries.
"The reason that rockfish in general aren't doing so good, is because they are so long lived, some of them can live over 100 years. So that means that when they reach reproductive maturity and they have babies, they're much older, and they're more likely to be fished out, if it takes them about 20 years to have babies."
Bulger adds the 9 sunken structures have to go follow thorough regulations to avoid polluting the ecosystem.
"Specifically with the Artificial Reef Society, they get what's called a 'Disposal At Sea' permit. They have to scrub up these vessels to Transport Canada and Environment Canada standards. And what they do is remove electrical casings, which have PCP's, which are toxins, in them. They also have to cut big holes in them to make them safe for divers. And they have to remove any petroleum products. The other thing is they can't be a hazard to navigation: they can't have big tall sails sticking up that are going to crash a ship, and they have to have markers there."
She suspects that the artificial reefs attracted more variety of sea life because they either suited the species's needs better than the natural environment, or because their previous habitat had been destroyed. Bulger will continue to work on finding out exactly why these fish are attracted to the sunken vessels.