Monday, October 18, 2010

Sustainable Seafood

Overfishing is the greatest threat to our oceans today. The world's marine life is quickly being depleted. An estimated 90% of all large, predatory fish are already gone from the world's oceans. A recent scientific study predicted a world-wide fisheries collapse by 2048. The only solution is to turn back from the brink, and to begin consuming seafood in a sustainable manner.

Sustainable seafood can be defined as species that are caught or farmed in a way that ensures the long-term health and stability of that species, as well as the greater marine ecosystem.

Ocean Wise’s Recommendations

Ocean Wise’s recommendations are based on 4 criteria. An Ocean Wise recommended species is:

  1. Abundant and resilient to fishing pressures
  2. Well managed with a comprehensive management plan based on current research
  3. Harvested in a method that ensures limited bycatch on non-target and endangered species
  4. Harvested in ways that limit damage to marine or aquatic habitats and negative interactions with other species.

Ocean Wise’s classification system is based on two categories: sustainable or unsustainable, simply a good or bad choice for our oceans. Species are regularly updated and/or reclassified with the latest scientific information. Classifications, including changes to and Ocean Wise recommendations are provided regularly to Ocean Wise participants.

Ocean Wise Recommendation Policy (PDF)

The Issues

Issues that trouble our marine environment in order to feed an ever-growing population include overfishing, bycatch and habitat damage.

Overfishing Global consumption of seafood has doubled since the 1970’s. Now, roughly 130 million tons of seafood is harvested every year. Improvements in fisheries related technology have allowed us to remove organisms from the ocean more quickly and with less effort, putting increased pressure on the oceans. With an estimated 90% of all large, predatory fish already gone from our world’s oceans since industrialized fishing began; we are now fishing the last 10% of species such as tunas, swordfish, and sharks. Quite simply our marine species can not reproduce fast enough to keep up with the hunt.

Bycatch Not all marine life that is captured by fishing gear makes it to the dinner table. An estimated 25% of what is caught in commercial fisheries is unintended catch (bycatch) and discarded. Bycatch can include unmarketable species, undersized species, and endangered species. Unfortunately the majority of the animals tossed back overboard do not survive. It is important to understand how your seafood has been harvested as some fishing gear types, like pelagic or surface longlining and bottom trawling can increase the likelihood and amount of bycatch incurred.

Habitat Damage Certain fishing and farming practices can have negative impacts on critical marine or aquatic habitats. With the loss of crucial habitats such as spawning, nursery, breeding or sheltering areas, many species find it challenging to survive, let alone thrive. Communities such as coral reefs, kelp forests, mangroves and wetlands provide critical habitat for a wide array of organisms and damage to these key areas can have dramatic consequences for the environment.

How Different Harvest Methods can beSustainable or Unsustainable

The different types of fishing and aquaculture techniques used to harvest seafood influence the environmental integrity of our marine ecosystems. This influence can be sustainable or unsustainable. The issues of bycatch and habitat damage and their extent are principally determined by the type of fishing or farming method used.

Fishing Techniques

All fishing techniques have to address a certain level of bycatch, however the type of harvesting technique determines the typical amount of bycatch associated. Certain fishing techniques are commonly associated with high bycatch such as trawling, dredging and pelagic longlining. Examples of seafood that typically involve high bycatch issues include shrimp, orange roughy, groundfish, scallops and other wild caught shellfish, large pelagic species such as mahi mahi, tuna and swordfish. However many of these species can be harvested with limited bycatch if the fishing method is sustainable. Sustainable fishing techniques associated with low bycatch include trolling, hook and line, pot and traps.

Certain fishing techniques can be associated with habitat damage and negative environmental impacts. Fishing methods that have detrimental effects on marine ecosystems include bottom trawling and dredging. In some cases, trawlers may sweep the same piece of seafloor many times a year, leaving no time for re-growth or recovery. Species that are typically caught by bottom trawl include: orange roughy, cod, shrimp, and ground fish such as flounder and sole. Dredges rake the ocean’s bottom habitat creating a disturbance in the seabed in order to sift out the targeted species, typically shellfish. Alternative sustainable fishing methods that limit habitat damage include trolling, hook and line and bottom longlining.


One third of the world’s seafood production comes from aquaculture. If done in a sustainable manner, aquaculture can help to take pressure off of wild stocks and provide a source of protein in areas where other alternatives are scarce. However, aquaculture can also have a negative impact on the environment and may actually harm wild populations through habitat damage and degradation, pollution, and disease outbreaks. The destruction of critical habitats such as wetlands and mangroves to create ponds, localized disease or parasite epidemics, and the pollution of marine or aquatic habitats are all very real concerns with various systems of farming.

Shrimp and prawns (such as tiger prawns) are typically farmed in coastal ponds that are created through the destruction of mangroves and wetland habitats and should be avoided. Open net pen finfish farms such as those used for Atlantic salmon also create major environmental concerns and should be avoided.

Sustainably farmed options include shellfish such as scallops, mussels, clams and oysters, which are farmed on lines or trays suspended from rafts and are more sustainable than their wild counterparts. Inland, closed system farms are another good alternative and include species such as rainbow trout, tilapia, channel catfish, sturgeon, and Arctic char.

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