Bottom-trawling: A case of Future Injustice
The oceans are the foundation for life. They provide a livelihood, food, medicine, energy and recreation for millions. Their currents and absorption of CO2 are crucial for the climate. Yet an ever-increasing variety and scale of human activities are degrading and destroying them.
More than 40% of the oceans are already heavily affected by human activities, according to an analysis by the University of California. This can be seen in the map below:
- Courtesy of Ben Halpern and the National Center for Ecological Analysis and Synthesis
To learn more about this map, please visit the website of the National Center for Ecological Analysis and Synthesis.
One of these activities which is potentially most destructive is bottom-trawling. Already it is impacting heavily on the oceans, tearing up the seabed and coral reefs, killing massive amounts of unused by-catch, and damaging fish stocks that poor people depend on for their nutrition. If it is not stopped, the impact on future generations could be immense.
On these web pages, you can read more about this practice, find out why it should be taboo and observe the early warnings of what could be a crime against future generations.
What is bottom-trawling?
- Trawl net on Oculina reef, Atlantic Florida © HBOI/NOAA/USGS
Bottom-trawling involves dragging very large, heavy nets – as much as 55 metres across and 12 metres high – over the seafloor to catch ground fish, shrimps and other species. The net is held open by heavy metal plates and is weighted down by a heavy steel cable footrope, to which rollers and, sometimes, chains are attached. The chains are used to flush out fish. The rollers help to weight and manoeuvre the net. These include small steel or rubber rollers - called "cookies" - used on flat sand and mud. And large moulded rubber rollers - called "rockhoppers" - measuring at least 1 metre in diameter, that make it possible to manoeuvre the nets around coral, boulder fields and rocky pinnacles.
A bottom trawl can sweep 33 km² of the seabed in a single trip – an area equivalent to about 5,000 football pitches. Nets with smaller mesh sizes target shrimp. Nets with larger meshes are used to catch gadoids, flatfish, rockfish or other bottom-dwelling species.
Bottom-trawling has increased – in depths over 1,000 metres – as fewer fish appear in shallower waters.
In March 2009, the FAO reported that in 2006, 285 vessels were involved in high seas bottom fisheries, legally catching 252,000 tonnes (excluding discards) with an estimated value of EUR 447 million. Most of these vessels were bottom- and mid-water trawlers. The top 5 vessel flag states were Spain, Korea, New Zealand, Russia and Australia. Click here for a table showing the total catch and number of vessels by region and here for the vessel flag involved in bottom fisheries.
But much bottom-trawling is unreported, unregulated and illegal.
Read more about the effects of bottom trawling here.
