It’s not too difficult to recall images of CAFO’s and cornfields from movies and magazines, but it’s often hard to imagine what an industrial fishing operation looks like. There are three main methods of commercial fishing and they all contribute to a vast sustainability issue known as Bycatch.
Bycatch refers to all sea creatures (fish, birds, turtles and some mammals) that are caught ‘unintentionally’ by commercial fishing operations and are usually thrown dead or dying back into the water. It is estimated that anywhere from 7 million to 27 million tons of fish and other species are discarded each year as bycatch. Tuna fishing, for example, has been shown to result in the regular killing of 145 other species including a wide variety of rays, sharks, dolphins, seahorses, albatrosses, sea turtles, whales and other fish.
Victims of Bycatch
Perhaps the least sustainable of all fishing industries is the world’s shrimp fishery. Shrimp trawlers drag huge nets along the ocean floor and haul in everything they catch, shrimp or otherwise. A single pass of a trawl removes up to 20% of the sea floor’s flora and fauna. Discard levels from shrimp fishing have been found to be as high as 20:1 with a world average of 5.7:1. Shrimp trawl catch makes up 2% of the world’s total catch of all fish by weight, but produces more than one-third of the world’s total bycatch.
Tuna fishing, by comparison, involves dragging nets through the water, high up off the floor of the ocean. An estimated 100 million sharks and rays and approximately 300,000 cetaceans (whales, dolphins and porpoises) die each year because they are unable to escape when caught in tuna nets.
Lastly, longline fishing, which catches the majority of other fish that people consume, does incredible damage to bird populations, interestingly enough. Lines are baited and dropped into the water. Birds dive for the bait planted on the lines, swallow it (hook included) and are pulled underwater and drowned. Approximately 100,000 albatrosses are killed annually because of this fishing method and many species are now facing extinction.
There are several proposed techniques for how to alleviate bycatch throughout the world. One approach is to ban fishing in areas where bycatch is especially high – but this option is not attractive to the industry who wishes to fish where the fishing is plentiful. A more reasonable approach is to encourage the use of alternative fishing gear. Simple solutions like nets with larger mesh sizes would allow smaller species to escape the catch. Furthermore, devices such as turtle excluders can be implemented to alleviate the bycatch of particular species. On a global level, probably the only effective way to address the problems of bycatch is to control fishing effort. This will be best achieved through the creation of marine reserves. Nonetheless, in the case of highly mobile species such as seabirds and cetaceans, the only effective way of preventing bycatch is to discontinue the use of these particularly damaging fishing methods.
A Turtle Excluder Device allows sea turtles to escape while the intended catch stays in the net.
Sources:
Greenpeace.org
Wikipedia.org
Foer, Jonathan Safran. Eating Animals
That is really good that they’ve made a turtle excluder thing. That is going to save a lot of sea turtles. In that first picture, is that some type of shark?
Thank you for your reply. The turtle excluder is definitely a big step toward alleviating turtle bycatch. The key know is to get more fishing operations to use the special nets. As for the picture, I’m not positive, but I would guess that is a shark based on it’s gills, although it could be a cetacean (whale/dolphin/porpoise order). Any sea life, whether fish, plant, mammal or bird can wind up on a boat deck as bycatch.