Fish is an important part of a healthy diet and global demand for seafood is on the rise. Just today I enjoyed some “sehr gut” smoked salmon endorsed by the European Union’s eco advisory “Ã?Â?ko Test.” “Sehr gut” means very good in German and it also means that the fish I was eating was caught from sustainable stock using a sustainable fishing method.
Fishing is central to the livelihood of 200 million people and one of five people worldwide depend on fish as a primary source of protein. It is no wonder that global marine fish stocks are in jeopardy from overfishing, irresponsible fishing methods and environmental degradation. Legislation has begun to help the oceans recover. Establishment of Marine Protected Areas (MPAs), like the one recently created in Hawaii by President Bush, are key aspects in protecting fragile marine ecosystems and reefs systems. However, these MPAs currently cover less than one per cent of the world’s oceans and seas.
Fishing is a consumer driven industry and consumers are responsible for large demand and the race to supply. However, overfishing threatens the food supply to millions of people. Making informed consumer choices will help support sustainable fishing methods. Commercial fishing is carried out through a variety of methods that employ different kinds of gear. Some methods are environmentally sound and some are not. Information here helps discern the good from the bad and the ugly. It can be used to make sound environmental consumer decisions about the fish you eat.
There are several factors to consider when determining the sustainability of a fishing method. These include the status of the species population, the extent of bycatch and the impact that the fishing method has on habitats, ecosystems and human communities. There are several different types of fishing methods worldwide. These include dredging, gillnetting, harpooning, hook and lining, longlining, purse seining, traps and pots, trawling/dragging and trolling.
Dredging as a fishing method causes significant habitat damage and is fatal to bycatch. Dredging is when fishermen drag a mesh bag attached to a heavy frame along the seafloor. The dredges often have metal teeth that rake through sand stirring up shellfish which flow into the bag. This fishing method is used to catch scallops, clams and oysters. As the dredges scrape along the seafloor, habitats are destroyed as plants and animals are smothered. Sponges, coral and fish are unintentionally caught and usually do not survive.
Gillnetting is another unsustainable fishing method for several reasons. A gillnet hangs in the water suspended by floats, weights and anchors. The netting is designed with mesh spaces that allow a fish’s head to pass through but not its body. When the fish attempts to back away from the net its gills become entangled and it is caught. While this fishing method can specify the size of fish it catches, allowing younger or smaller fish to pass through unharmed, it can entangle unintentional species like sea turtles as bycatch. This fishing method can also cause damage to habitat by entangling coral and other natural formations damaging fragile ecosystems.
Harpooning is an example of an environmentally responsible fishing method. It is a traditional method that is used to catch large fish like bluefin tuna and swordfish. When a fish is spotted, the fisherman thrusts or shoots a long harpoon into the animal. This fishing method requires the fisherman to visually identify the catch before exerting the physical energy to kill it. It does not produce any unwanted bycatch and does little to impact habitat.
Hook and lining is a popular sport fishing method and can be environmentally responsible. Fishermen who practice this fishing method use a line with hooks and bait meant to attract certain fish. The line can be attached to a rod or held by hand. This fishing method targets a wide variety of fish including tuna, mahi mahi, cod, salmon and trout. Since this fishing method requires that the catch is hauled in manually, unwanted catch can be quickly released alive. Trolling is a form of hook and lining and how my “sehr gut” salmon was caught. It is similar to hook and lining except many lines are set at the same time. This fishing method is used to catch salmon, mahi mahi and albacore tuna. Like traditional hook and lining, trolling is an environmentally responsible fishing method as unwanted catch can be released soon after it is caught.
Longlining is a highly lucrative, dangerous and environmentally damaging fishing method. The practice has been scrutinized by marine biologists and ornithologists. It has also gained public sympathy through media portrayals such as the film The Perfect Storm which documented the difficult and dangerous lives of long line fishermen. Longlining sends baited fishing lines out courses of more than 50 miles. Set to a central line, smaller lines dangle at spaced intervals. The lines are left for long periods to attract open ocean species such as tuna, swordfish, cod and halibut. When hauled in the longlines reveal a list of unwanted bycatch including endangered species like sharks and sea turtles. Seabirds often become entangled in lines and hooks as they dive for the bait fish. This fishing method is costly to human life as well as the possibility of injury is ever present.
Purse seining uses a large wall of netting to encircle schools of fish. The netting is pulled closed like a drawstring purse. The net can be hauled aboard or alongside the boat where the fish can be scooped out. This method is popular for catching sardines, squid and tuna. Purse seining has contributed to the decline of dolphin populations and includes sharks, sea turtles and juvenile fish in its bycatch. Adaptations to the nets have become more dolphin friendly but the species has yet to recover.
Traps and pots are wire or wood cages that are submerged with or without bait. They attract fish and hold them alive until the gear is hauled in. Fisherman run a rope from the trap or pot to a floating buoy at the surface. This fishing method is used to catch lobsters, crabs and shrimp. The traps may cause damage to habitats along the seafloor if bounced around or when hauled in and it is not uncommon for marine mammals to become entangled in the buoy lines. However, compared to other fishing methods, using traps and pots tends to be environmentally friendly and has a low bycatch as unintended species can be released alive. The potential for damage or bycatch is related to the scale of the fishing operation. Some operations are small such as lobster pots and some are large scale such as Alaskan king crab traps which can weigh up to 700 pounds.
Trawling involves towing a cone shaped net behind a boat. The nets are set at various depths from just below the surface to the seafloor. Trawl nets catch everything in their path and like dredging, can damage the seafloor habitat. Bottom trawling as a fishing method has been compared to clear cutting forests. The nets can catch a significant amount of bycatch including endangered sea turtles. This fishing method can employ bycatch reduction devices to allow sea turtles and unwanted species to escape. The potential damage to seafloor habitat can be avoided if fishermen avoid rocky or coral habitats. Mid water trawling avoids the surface and seafloor. It produces little bycatch and doesn’t disrupt seafloor habitats.
How these fishing methods affect the environment is of global concern. The magnitude of the crisis facing marine fish stocks and ecosystems is underemphasized amid other environmental issues. Nearly 70% of the world’s fish species are either fully exploited or depleted. Destructive fishing techniques destroy marine mammals and entire marine ecosystems. Illegal and unregulated fishing is increasing in response to stricter rules. Supporting sustainable fishing methods requires cooperation between government, fishermen, communities and consumers. As a global food source the importance of maintaining a sustainable fishing industry can’t be overlooked. As individuals our part is to make responsible consumer choices that support environmentally responsible fishing methods.