Trawling Towards Disaster: Impacts of Commercial Fishing on Ocean Biodiversity

Photo by neptunecanada |

Imagine an enormous commercial fishing boat with a trawler dragging along the bottom of the sea floor, scraping all delicate features in its path with no care as to what is taken or damaged by the unforgiving nets.  The unpleasant truth of the devastation caused by fishing boats and trawlers is not much of a surprise these days. Rather, it’s the elimination of species we may not even have identified yet.

Bottom trawling, just like it sounds, is the process of commercial fishing boats dragging a large net along the bottom of the ocean floor to capture as many target fish as possible.  Along the way, however, undesired fish and animals are caught as well.  Within the sorting process, they are simply thrown back into the water, usually either dead or dying from the tragic experience. 

Potentially more troubling is how this process permanently eliminates currently unidentified species from aquatic ecosystems.  The ocean floor may be home to 10 million species – think of the biodiversity in a tropical forest, but underwater.  The bottom surface of oceans were once avoided by fishing boats because nets were easily damaged, but since this problem has been solved, nets are dragged along the surface, destroying entire ecosystems with just one motion. 

Direct obliteration isn’t the only concern with bottom trawling – sediment and contaminants are disturbed and re-released into the water.  Suspended solids can interrupt or disturb photosynthesis for marine plants, and organic pollutants consumed by species bioaccumulate and biomagnify in the food web.  This combination of direct destruction, eutrophic conditions and pollutant overload is responsible for removing species from our oceans before humans have even been able to identify them. 

Fortunately, there are things that can be done to reduce the destruction caused by commercial fishing.  Bottom trawling has been banned by the United States in its offshore jurisdictions, although Europe and other locations are yet to do so.  The DSCC (Deep Sea Conservation Coalition) now has more than one thousand scientists from nearly 70 countries addressing their concerns regarding bottom trawling and other harsh fishing practices.  Furthermore, requests by the DSCC have been made to better protect undiscovered marine biodiversity. 

As bottom trawling and related methods of large-scale capture become evident to the public, continued pressure by environmental advocacy groups and individuals alike will help force commercial fishing companies to find more environmentally-sensitive alternatives to bottom trawling.

To find out more about the DSCC, visit  

Mandy McDougall