VANCOUVER (NEWS 1130) – A study out of UBC found the practice of bottom trawling which involves dragging a fish net across the seafloor, has wasted 437 million tonnes of fish and missed out on $560 billion in revenue globally over the past 65 years.
In fact, along BC’s coast 26 per cent of fish are caught by bottom trawl fisheries. Tim Cashion, a PHD student for the school’s fisheries economics research unit for UBC, explains this practice is prevalent because the expensive fish dwell near the bottom.
“Likely because you can catch a lot of high-value species in that way, you can think of cod fisheries off of the east coast of Canada or the mix ground fishery off of BC.”
The study is a part of the Sea Around Us initiative at UBCs Institute for the Oceans and Fisheries, which looked at the growth of bottom trawling between 1950 and 2014.
Cashion found there are a couple of places that have either already closed bottom trawling or are about to.
“So Hong Kong is one, Belize is another, and there are some new protected areas being put in place in Canada where bottom trawling will be banned. Those are still kind of small, isolated areas and although that is good, it means the practice will largely continue.”
The areas in Canada that Cashion is referring to are the coasts of Nunavut and Newfoundland and Labrador.
BC still using bottom trawling
As for BC, bottom trawling is the method that continues to be used but there is also trap-caught. Cashion says trap-caught is a better method because it reduces harm to other species.
“You’re going to lower the traps down onto the ecosystem so you’re not disturbing the water or catching everything in the path of your boat. But you’re catching what goes into those traps you can think of lobster traps or crab traps these would be similar, and shrimp traps would operate in a very similar way. Where the crab, lobster, or shrimp crawls into the trap first for the bate then is unable to get out, then you raise that out of the water.”
Cashion says using the trap-caught method makes it easier to release species and their chances of survival are higher, unlike the bottom trawl method the chance of survival is much lower.
Also in the study, they compared small-scale fisheries to large-scale fisheries. Cashion says they find small-scale farming is better because it can lessen the environmental harm.
“The waste or the high incidences of this practice of discarding is kind of a product of catching so much fish when you’re targeting something very specific, whereas small-scale fishers have more options to distribute a wide diversity of species to the people that are buying the fish,” he says.
“So what we found when we looked at comparing those large-scale and small-scale fisheries, is small-scale fisheries have much less discard, so much less waste fish that is thrown overboard and not landed at the dock. And the value of the fish was much higher for small-scale fisheries then large-scale fisheries.”
Cashion says things can be done to harm fewer species.
“I think there’s a lot of room for improvement by being more selective with the way that you fish and the way that different fishing gears are deployed. So if you are trawling that could be changing the size of the mesh in the net that your dragging to only catch those larger fish. Or it could be not fishing in certain areas in certain times of the year where we know you’re going to be catching a lot of fish that you don’t want.”