Forage Fish Matters: Microplastics and our Forage Fish


I remember when I bought my first polar fleece jacket in about 1990. I felt so happy to know that I was supporting the recycling movement by purchasing this fabric spun from used plastic pop bottles. In 2015, I was horrified to see the results of the water analysis from samples I had sent in as part of a Microplastics Investigation Project. My samples were taken right here in False Bay. They showed, on average, 2 pieces of microplastic filaments per litre of water analyzed. One possible source? You guessed it, polar fleece (polypropylene) or other synthetic clothing (polyester, nylon, acrylic) filaments washed into the sea from human waste water. Whether it's our tarps, shedding tiny plastic bits until they feel like well worn fabric, our plastic garden covers and plant pots, our fraying synthetic ropes, floats breaking up into styrofoam bits or our wash water discharge, life on Lasqueti seems to demand that we participate in creating microplastics. The numbers are interesting to look at. From the north Salish Sea, they found 2 pieces of microplastic per litre of sea water; down in Squamish, a whopping 20 pieces of microplastic per litre. Our human footprint!

Another concern, plastic microbeads, have in recent years been purposefully produced and sold in such diverse products as tooth paste, skin scrubs, medications and industrial sand-blasting products. Thankfully, the Canadian, American and some other governments have declared plastic microbeads to be "toxic substances" and are taking steps to phase out their inclusion in personal use products over the next 3 years. They will continue to be flushed into our waste waters, rivers and oceans until then.

Unfortunately, banning the production and use of plastic microbeads will not solve the problem of plastic trash which continues to enter the marine environment. In addition to shedding from our clothing, so much microplastic comes from these larger pieces of plastic trash: remember those ocean gyres of plastic, slowly breaking down by sunlight and mechanical wear, creating ever smaller fragments of plastic which eventually become invisible, but still very present in the water column. Researchers have estimated that for every kilogram of plankton in the Pacific gyre, there are 6 kilograms of plastic.

We humans keep adding to the gyres and the oceans' burden. Aquaculture, fishing, boatyards, marinas, sewage treatment plants, grey water disposal systems, landfills and industrial plastics manufacturing plants are all direct sources of marine plastic. Even our inland urban centres are huge sources of marine trash delivered by our rivers and on the wind. Worldwide estimates are that one trillion plastic bags alone are used each year requiring 100 million barrels of oil! Global production of plastic increases by about 9% per year. In 2012, 288 million metric tons of plastic were produced worldwide. About 10% of municipal waste is plastic and 10% of all this plastic trash ends up in the ocean. This does not include those plastic microbeads which, until recently, were completely unknown and still remain unaccounted for.

There are consequences to all of this plastic entering our marine environment. Due to their different densities, microplastics have been found throughout the entire water column. Plastic bags undulate like jellyfish and tiny microplastic filaments glisten like plankton; marine creatures confuse this floating plastic with food. Breaking down, plastics release "loose monomers" which are toxic in themselves. They also contain toxic chemicals from the manufacturing process that leach into the water column and into the animals that ingest it. Plastic also attracts and concentrates a very long list of unpronounceable chemicals such as DDT (still!) & PCB's, up to 30 or more times higher than in the surrounding sea water. They become vectors for these very harmful chemicals transporting them around the world and enhancing the toxicity of the microplastic bits that are ingested by marine life.

The numbers are mind-numbing. Causing entanglement, digestive tract blockages and toxicity, one million seabirds are killed each year by floating plastic. Hundreds of thousands of sea turtles, whales and other animals die. Estimates by the Scripps Institute of Oceanography (University of California) are that fish eat 12,000 - 24,000 tons of plastic each year in the Pacific ocean alone. Microplastics are also eaten by filter feeders such as oysters, clams and mussels - would you like a little 'Polar Fleece' with your sushi?

Zooplankton also eat phytoplankton and,    inadvertently, microplastics. Now, remember our little forage fish that spawn from November until March here on our Lasqueti Island beaches. Our Surf smelt and Pacific sand lance eat plankton, and can't tell the difference between real food and those microplastic filaments (2 per litre in False Bay) that are the same size as the phytoplankton naturally in their diet. They also eat the secondhand microplastics that have been ingested by the zooplankton, their other favourite food. Recent studies on forage fish in Europe have shown the detrimental affects that ingesting styrofoam micro-bits has on these species. It affects all stages of life for these forage fish and results in poor reproduction for those that survive. Then, up the food chain it goes, increasing in concentration in the top predators. Yes, if you eat fish you could be ingesting some of the toxins contained in plastic.

So, a heart felt thank-you to those who have helped to clean up our Lasqueti Island beaches this past summer and to those who just bend over and pick up plastic trash. Congratulations to those who search out and use alternatives to synthetics in their clothing and plastics in their daily life. Dare to imagine a plastic free island. The future is in our hands!

Connie Haist