Plastic in our Oceans
Plastic is filling our oceans at an alarming rate of one dump truck full every minute around the world. From pole to pole, ocean currents are spreading plastic particles to the most remote corners of our world.
In the ocean, plastic doesn’t break down. It breaks up into increasingly tinier fragments, creating a sea of tiny particles called microplastics.
All this plastic is having a big impact on ocean life.
One of the world’s largest seabirds, the albatross, faces threats because of plastic ingestion. Plastic has been found in mussels, fish, sea turtles and marine mammals. Plastic is also entering the ocean as microfibres shed from synthetic textiles in our laundry. Research by Ocean Wise®, headquartered at the Vancouver Aquarium, shows that up to 80 per cent of the microplastic pollution on Canada’s West Coast is plastic microfibres.
Ocean Wise researchers have found widespread microfibres in wastewater in the coastal city of Vancouver. They’ve also discovered tiny zooplankton at the base of the ocean food chain are ingesting microfibres – highlighting the need for more research on microplastic impacts on ocean species.
seabirds and their prey
Dr. Peter Ross, Ocean Wise vice-president of research, has been working with teams at Environment and Climate Change Canada and Parks Canada to examine what role Pacific forage fish – that provide food for seabirds – might play in transferring microplastic particles through the ocean food web.
In a recent study, Dr. Ross collaborated with other researchers to test two types of forage fish – Pacific sand lance and Pacific herring.
These small fish are abundant in the Salish Sea of the Northeast Pacific and depend on a diet of zooplankton. They also provide food for the rhinoceros auklet, a seabird common to the British Columbia and Washington coast.
Auklets dive for their prey and deliver them to their nestlings – making it easy for researchers to collect the fish when the birds return to the colony. Samples were taken from the nests of six auklet breeding colonies over a period of eight years.
Monitoring for plastic pollution
The North Pacific Ocean is a global hotspot for pollution, but this study concluded that forage fish on British Columbia’s outer coast were not carrying microfibres in significant amounts through the food chain.
Researchers did find higher levels of microfibres, however, in the fish collected in the protected inner waters of the Salish Sea. Scientists say extensive urban development along the shoreline is probably the reason, but could not explain why the levels varied from year to year.
While it’s not clear what this might mean for shorebird health, researchers say these results clearly demonstrate the need for continued monitoring of microplastics at sea and in ocean life.