The Destruction of Our Oceans: Bottom Trawling

By Wesley Cotter

 Over the past few decades, more fisherman have turned to bottom trawling as opposed to traditional fishing methods. With a mouth over 200 feet wide, trawling nets swallow everything in their path. They destroy countless habitats and put numerous marine species on the brink of extinction. However, it wasn’t until recently that technology allowed scientists to fully examine all of trawling’s negative effects.

With recent innovations such as effective underwater cameras and advanced satellite imaging, it is evident that bottom trawling is slowly destroying the world’s oceans. Not only does trawling kill off entire marine populations, but it also makes marine ecosystems inhospitable for years to come.

Although bottom trawling has been damaging the marine ecosystem for generations, not many people actually know what bottom trawling is, or how it works. Bottom trawling is a common fishing practice that has gained popularity among fisherman for its ability to reel in huge catches. Basically, the process of bottom trawling involves dragging a huge net across the sea floor, scooping up anything in its path (Oceana).

The overfishing caused by bottom trawling is destroying our planet’s ecosystem. Bottom trawling leads to overfishing, which means that fisherman are catching fish faster than they can reproduce. As a result, scientists have estimated that the world’s fisheries will be depleted by the year 2048 --> (Eilperin). However, we do not need to wait another 36 years until a fish species dies out. Trawling has already put the Orange Roughy and Barndoor Skate fish species at the brink of extinction. Disturbingly, trawlers are not even interested in catching Barndoor Skate, as they are just by-catch, meaning they were caught unintentionally while trying to catch other fish. Regardless of the intentions, the Barndoor Skate are killed along with the intended species (Barndoor Skate). Scientists estimate that for every 1 pound of usable fish caught trawling, 16 pounds of marine life are killed (Oceana).

However, it wasn’t until the creation of an effective underwater camera that scientists fully understood trawling’s negative results. It was previously assumed that trawling benefited the fish populations because recently trawled areas, when re-trawled, held even larger catches the second time around. Originally, it was assumed that like plowing a field, trawling benefited growth (Chestney, Nina). Though once investigated, it was discovered that it was just marine animals feeding on all of the dead marine life, rather than a regrowth of the population.

Along with killing off entire marine populations, trawling severely damages the marine environment as a whole. Trawling has been compared to forest clear cutting, where hundreds of years of coral and other natural structures that are vital in sustaining life are destroyed (Chestney, Nina). This process devastates many marine habitats, and the erosion caused by the nets takes decades to be reversed. Its estimated that an average trawler can destroy 580 square miles of seabed per day, and that annually, the world’s trawling fleet goes over an area twice the size of the continental United States (Oceana). The rate at which the ocean is being destroyed is significantly faster than the deforestation of the rainforest.

Additionally, as the nets are dragged along the seafloor, enormous plumes of sediment will be disturbed. At first thought, this is of no consequence, but as scientists looked deeper, they realized it had many negative effects. With the recent creation of satellite imaging, it’s easy to see how far the plumes will spread. Google earth images will show distinct sediment trails that continue for miles. Due to the currents, the plumes will drift and displace the oxygen in the water, creating an oxygen deficient dead zone. This dead zone will either kill off all plant and animal species in the area, or force them to relocate (Teach Ocean Science). Also, the disturbed sediment will reintroduce pollution that had once settled into the seafloor. This pollution is extremely harmful to both the plant and animal life, often being fatal. 

Sediment Plumes off the Coast of Louisiana

Its evident that bottom trawling has serious environmental consequences. Trawling kills off entire marine species, and creates regions of oceans that can no longer harbor life. The actions taken in the next few years are pivotal for the revival of our oceans. If regulations and laws are quickly imposed and strictly regulated, we may have a chance to save our oceans (Save Our Seas). Specifically, we need to create more Marine Protected Areas (MPA) where fishing and other environmentally harmful activities are forbidden (About MPAs). Currently, 1.17% of the ocean is a MPA, but in order to make a significant difference, we need to protect more of the ocean. However, none of this will really matter until the world’s citizens take a stand, and we become aware of our global impact.

The following is a very informative video on bottom trawling. If you’re actually interested in the subject, I definitely suggest watching it. Also, it’s narrated by Sigourney Weaver.
http://www.youtube.com/watch?v=-0616msQC_M

About Marine Protected Areas, Department of Commerce, http://www.mpa.gov/aboutmpas/

Barndoor Skate, journal.nafo.int, http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CEQQFjAF&url=http%3A%2F%2Fjournal.nafo.int%2F35%2Fgedamke%2F19-gedamke.pdf&ei=FR9qUPqqJ4ru9AStlYCYAQ&usg=AFQjCNHSqWaBOZLVMvbO4apUT7Zy2STmlg&sig2=VN_EFB53Eqenjsk8imAM6w

Bottom Trawling, Greenpeace, http://www.greenpeace.org/international/en/campaigns/oceans/bottom-trawling/

Dead Zones, Teach Ocean Science, http://www.teachoceanscience.net/teaching_resources/education_modules/dead_zones/learn_about/

Eilperin, Juliet, World’s Fish Supplies Running Out Researchers Warn, Washington Post, http://www.washingtonpost.com/wp-dyn/content/article/2006/11/02/AR2006110200913.html

Nina Chestney, Trawling Could Harm Oceans Like Plowing Land, Scientific American, http://www.scientificamerican.com/article.cfm?id=trawling-could-harm-oceans-like-plo

Overfishing, Save Our Seas, http://saveourseas.com/threats/overfishing

What is Trawling?, Oceana, http://oceana.org/en/category/blog-free-tags/deep-sea-trawling