University of Victoria researcher Garth Covernton, with the help of students from Vancouver Island University, is studying oysters and clams to help determine the levels of ‘microplastics’ in the waters off Vancouver Island.
The teams will tag more than 2,000 oysters and 1,000 clams, working out of VIU’s Deep Bay Marine Field Station on Vancouver Island opposite the southern tip of Denman Island.
“Microplastics are too small to see with the eye and because of that they can easily enter a wide range of organisms’” said Covernton.
“Waste water treatment plants don’t pick them up and they cannot be easily digested or broken down by bacteria, which is why they persist in the environment.”
VIU’s Dr. Sarah Dudas, a biology professor at VIU, said microplastics can absorb and concentrate chemicals, then end up being eaten by marine organisms, which make them an emerging threat to wildlife, ecosystems and human health.
“We are looking at shellfish because they are filter feeding organisms’” Dudas said. “They accumulate anything that is in the water and they live on the coast where the most drastic changes are happening, which makes them excellent sentinels of ecosystem health.”
Microplastics are generally described as smaller than five millimeters and can include everything from plastic microbeads that are used in rinse-off cosmetics and toothpaste products, to the thousands of plastic fibers that come off our fleece clothing every time they go through the wash.
Secondary sources of microplastics are simply larger pieces of debris that have been broken up and worn down by the waves, wind and sun. A study recently published in Science Magazine estimated that in 2010 between 4.8 and 12.7 million metric tons of plastic was entering the ocean annually.
It is likely the amount of plastic waste – including microplastics – in the ocean will continue to increase, driven by the rise in plastics consumption (about 9% per annum) and the continued inadequacy of re-use, recycling and waste management practices in many parts of the world, according to greenfacts.org.
Covernton’s study is being funded by the Department of Fisheries and Oceans and the BC Shellfish Grower’s Association, which represents a shellfish farming community that provides over 1,000 full-time jobs in rural and coastal BC communities and accounts for over $33 million in shellfish farm sales annually.
Association president Steve Pocock said the growers were excited to work with VIU on the study because anything that affects the oceans is a concern to them as a community. “Our lives are spent on the ocean so anything that could potentially impact the health of the coastal ecosystem is of interest to us,” said Pocock.
The VIU students are using felt pens to handwrite identification numbers on the oysters and clams, then measuring the shells so that when they are collected again in the fall, Covernton will know how much they grew.
The tagged oysters and clams have been released at 22 beaches, 11 shellfish farms and 11 wild sites, located in four Vancouver Island coastal regions. Covernton will re-harvest them in September to determine how much microplastics they consumed over the summer.