According to a new study, carried out by the Sea Around Us initiative at UBC’s Institute for the Oceans and Fisheries (IOF), industrial fisheries that rely on bottom trawling wasted 437 million tons of fish and missed out on $560 billion in revenue over the past 65 years.
Bottom trawling is the practice of fishing where ships drag large nets along the sea floor and pull up unwanted or unneeded fish. The study documented the growth of bottom trawling from 1950 through 2014 and the research found that bottom trawling generates the most waste of any fishing method due to the destructiveness and unwanted catch that is dumped back into the ocean.
Tim Cashion, the lead of the study a PhD student at IOF said, “Industrial fisheries do not bring everything they catch to port. During the period we studied, they threw out more than 750 million tons of fish and 60 per cent of that waste was due to bottom trawlers alone.”
Cashion and his colleagues identified the fishing tools used by industrial and small-scale fisheries in each maritime country and territory and paired them with the millions of records in the Sea Around Us catch database that include reported and unreported catches by fishing country, fishing sector, year and species.
They found that globally, industrial and small-scale fisheries caught 5.6 billion tons of fish in the past 65 years. While almost 28 per cent of all fish was caught by industrial bottom trawling, this fishing method also generated the most waste, accounting for nearly 60 per cent of the fish dumped back into the ocean.
Small-scale fisheries were responsible for 23 per cent of the global catch or approximately 1.3 billion tons in the past 65 years. However, their catch was worth significantly more because they use small gillnets, traps, lines, hand tools, and similar utensils to catch the fish they want.
According to the researchers, calculating the amount of waste generated by different fishing tools and practices, as well as knowing what’s brought to shore and used is crucial to evaluating the costs and benefits of fisheries at national and global levels.
The findings are astonishing on their own but highlight a destructive reality our oceans are facing. An estimated 70 percent of fish populations across the world are fully used, overused, or in crisis as a result of overfishing and warmer waters. The data can be used in a variety of ways to help protect and rebuild fish stocks but one thing that is evident, we need lawmakers to restrict bottom trawling, particularly in areas that are fragile.