Sustainable Seafood Glossary of Terms


David Barouh displays fresh fish for sale at Seattle’s Pike Place Market.

Credit: © Rich Frishman

Aquaculture - a form of food production involving the cultivation of commercial fish and shellfish species under controlled conditions. Aquaculture currently takes place in contained ponds and along the coast; but offshore aquaculture has begun to gain popularity in open ocean environments. Inland operations include closed tank systems, ponds, and runways.

Biological Overfishing - when too many fish are harvested from a fishery, there remain too few individuals to reproduce quickly enough to sustain the population at a healthy level.

Biomass – when used in fisheries management it refers to the total population of a particular commercial fish species. Bycatch - ocean animals that are incidentally caught when fishing for other targeted animals.

Bycatch Reduction Device (BRDs) - a device put into fishing nets (usually trawl nets in shrimp fisheries) that allows non-targeted species (juveniles, finfish, sea turtles, and other potential bycatch) to escape alive while the targeted species is directed into the net.

Catch Share - a type of fishery management that allocates a specific percentage of the total allowable fishery catch or a specific fishing area for the exclusive use of individuals, cooperatives, communities, or other entities (see also IFQ and Limited Access Privilege).

Closed Tank System - an aquaculture system in which there is some kind of barrier between the farmed fish and the marine environment, generally by a solid walled tank floating in the water or a lined tank on land.

Commercial Overfishing - when too many fish are harvested from a fishery, there remain too few individuals to reproduce quickly enough to economically sustain a commercial fishery.

Community Supported Fisheries (CSFs) - a marketing approach, rather than a management strategy. It is an arrangement between residents and businesses in a fishing community based on the success of Community Supported Agriculture (CSA) arrangements. Members of a CSF support the fishermen paying in advance for their share of fresh-caught seafood. Fishermen get upfront capital to support fishing for the season.

Dredging - a fishing method that involves a heavy frame with an attached net that is dragged along the sea floor; dredging can cause serious damage to the sea floor and benthic habitats.

Essential Fish Habitat - any habitat that is necessary for fish spawning, breeding, feeding, or growth to maturity.

Federal Shellfish Tagging Program - the Federal Shellfish Tagging Program monitors and tracks shellfish in the United States to prevent shellfish from being illegally harvested from unsafe areas and then being sold to the public. Shellfish growing waters that are certified are regularly monitored for health hazards. Restaurants and markets must insure that all shellfish they buy and sell is tagged as certified.

Feed Conversion Ratio (FCR) - in aquaculture, the feed conversion ratio is the kilogram or pounds of food required to increase the biomass in the pond by one kilogram or pound. Many factors go into determining the optimal FCR and can be overlooked in fish husbandry.

Individual Fishing Quotas (IFQs)/Individual Transferable Quotas (ITQs) - a management tool that assigns individuals in a fishery the right to harvest specific portions of the total allowable catch (see TAC below). The quota may be transferred to another fisherman for a fee equal to the commercial value of that quota. Recently replaced by Limited Access Privilege programs (see LAP below).

Invasive Species - a species that is non-native to a specific ecosystem and its introduction causes or is likely to cause damage to the ecosystem or humans.

Limited Access Privilege (LAP) - a legal term referring to specific forms of catch share management options, including the former IFQs and certain community/cooperative exclusion quota programs.

Long-line - gear in which thousands of baited hooks are laid along miles of ocean, often results in bycatch including sea birds, sharks, and sea turtles. Circular hooks are being implemented to reduce capture of turtles and make it easier to remove fish from the hooks.

Maximum Sustainable Yield - the largest amount of a species that can be removed from the fishery over an indefinite period while still allowing for a commercially viable future.

Mercury - present in nature but can also fall from the sky as a component of some industrial pollution and then accumulate in streams and oceans. As it does, it becomes methylmercury in the water. Methylmercury can be harmful to a fetus or young children. It can accumulate in the fatty tissues of fish that ingest it and can have detrimental impacts as the accumulated methylmercury moves up the food web. It is harmful to a fetus or young children and pregnant women are encouraged to avoid fish that are known to have large amounts of methylmercury.

Ocean Pen Farming -same as open ocean farming.

Omega 3s - a family of unsaturated fatty acids, the human body does not produce omega-3s by itself and they have been shown to protect the heart. Researchers suspect it can fight cancer. They are widely found in seafood.

Open Ocean Farming - open net pens enclose fish such as salmon in offshore coastal areas or in fresh-water lakes. Net pens are considered a high-impact aquaculture method because waste from the fish passes freely into the surrounding environment, polluting wild habitat. Farmed fish can also escape and compete with wild fish for natural resources or interbreed with wild fish of the same species, compromising the wild population. Diseases and parasites can sometimes spread to wild fish living near or swimming past net pens.

Optimum Sustainable Yield - the largest amount of a species that can be removed from the fishery over an indefinite period while still allowing for a biologically viable future.

Polychlorinated Biphenyls (PCBs) - PCBs are a class of persistent organic compounds that were used as coolants and insulating fluids. Even though PCB production was banned in the U.S. in 1979, they persist in the environment and leach into waterways and the ocean. PCBs accumulate in the fatty tissues of fish that ingest it and can have detrimental impacts as the accumulated PCBs move up the food web. They are toxic to humans and animals, causing conditions from rashes, headaches, anemia, birth defects, and, in many animals, liver damage and death.

Pond Farming – enclosed fish in a coastal or inland body of fresh or salt water, shrimp, catfish, and tilapia are commonly raised in this manner. Wastewater can be contained and treated. However, the discharge of untreated wastewater from the ponds can pollute the surrounding environment and contaminate groundwater. The construction of shrimp ponds in mangrove forests has destroyed more than 3.7 million acres of coastal habitat important to fish, birds, and humans.

Purse Seine - large netting used to capture a school of fish. Once the school of fish is surrounded the fishermen pull the bottom of the net closed (like a purse-string) and trap the fish inside.

Red Tide - under certain environmental conditions, marine algae can quickly grow, making the ocean look red. These algae produce toxins which are deadly to fish and other marine life. In addition to killing fish, these toxins accumulate in the tissues of the shellfish that feed on it. This in turn causes poisoning in humans that eat the shellfish.

Spawning Aggregation - when a large number of the same species aggregates in a specific site temporarily to reproduce; these species are particularly susceptible to overfishing during these aggregations.

Stakeholder - when referring to the ocean, any group or individual concerned about the state of a fishery or ocean resources impacted by a fishery. This can include fishermen, communities, environmentalists, recreational users, and many others.

Total Allowable Catch (TAC) - total limits of how many of each species can be caught, usually set by fishery managers, regulations, or fishing communities.

Tragedy of the Commons - a scenario developed by Garrett Hardin to describe what can befall “common” limited resources. The tragedy of the commons tells the story of a town commons in which anyone could graze their sheep. Each shepherd, as a rational being, wanted to increase their own immediate wealth, and subsequently increased their stock without limit. Each additional sheep only degraded the commons incrementally, yet as all shepherds increased their stock, the impact on the commons became extensive because the resource was limited. Since no one owned the commons, no one thought about the future health of the commons. Each shepherd was compelled to keep increasing their stock until the commons could no longer be used for grazing. This scenario is frequently used to describe what occurs in a common resource such as a fishery. It is because of this tendency that fishery managers are turning toward LAPs (see above) or catch shares. In these fisheries, each fisherman (or fishing community) is given incentive to think of the future of the limited resource since their wealth is dependent on the current and future health of the fishery.

Traps - baited cages made of wood or wire used to capture targeted species and keep them alive until they are hauled in. Can be damaging to the habitat in which they are dropped, but generally have lower bycatch than other fishing methods.

Trawling - fishing gear made of large nets (up to the size of a football field) that are dragged through mid- water or along the bottom to capture all fish (and incidental bycatch) in its path.

Turtle Excluder Devise (TED) - a grid of bars added to the top or bottom of a trawl that allows small animals to pass into the trawl net, but lets larger animals, like marine turtles, to be ejected through the opening when they strike the bars.

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