Aquaculture: The rearing or cultivation of aquatic animals or plants for food, e.g. mussels, oysters, salmon. Also called ‘fish farming’.
Broodstock: The individual fish reared for the purposes of providing eggs and larvae for ongrowing in aquaculture production. These fish are generally treated quite differently to those reared for production, and may be sourced from the wild or have been reared in captivity as part of a selective breeding program.
Bycatch: Aquatic life that is killed or damaged during the fishing process but is not retained as catch and sold. Bycatch generally refers to endangered wildlife that may be protected under Australian law, e.g. soft corals, sea turtles, albatrosses, endangered sharks.
Byproduct: Any fish or shellfish species that is caught and retained in a fishery before being sold to the market but is not actively targeted/sought by the fishery.
Capture fisheries: Wild aquatic species that are caught for sale from the natural environment using a range of fishing methods.
Closed or recirculating system: An aquaculture system that is not connected to the natural environment, that recycles most or all water used for production.
Depleted: Overfishing has reduced a stock to a very low level of abundance, requiring rebuilding of stock, e.g. Southern bluefin tuna, school shark.
Discarding: the practice of returning unwanted catches to the sea dead or alive, either because they are too small, the fisherman has no quota, they are of low value or because of fishery rules.
Ecosystem: An interacting and interdependent community of living organisms and physical structures that functions as a unit in nature.
Electronic Monitoring: Digital cameras are fixed to fishing boats and record fishing activity. Recorded footage is checked to ensure fishers are reporting their fish catch and bycatch correctly in Logbooks. Electronic monitoring has replaced Observers in many instances around Australia and has become an essential component of good fisheries management.
Environmentally limited: A fishery with reduced productivity due to external impacts associated with habitat modifications or environmental factors. Reduced stock levels are not primarily due to fishing, although fishing may be a contributing factor to concerns regarding low stock levels.
Extinction: Commercial extinction – a species is depleted to the extent that it is no longer commercially viable to fish. Ecological extinction – a species has declined to such low abundance that it ceases to play its role in the ecosystem. Biological extinction – a species is permanently lost, with no living members still in existence. Local extinction – A species may have viable populations in some areas, but can be described as one of the aforementioned extinct states in a particular region.
Fishing effort: The level of fishing pressure employed over a set timeframe. Often measured as number of hooks or traps deployed, hours trawled, or length of net used. The quantity of fish caught relative to the amount of fishing effort used is an important indicator of fishery health, where stable or increasing catches relative to fishing effort over time is a desirable outcome.
Fully fished: A fish stock is ‘fully fished’ when fishing pressure is at the maximum or targeted limit (typically Maximum Sustainable Yield) of what can be sustained before overfishing will likely occur.
Ghost fishing: The accidental capture and killing of marine wildlife in fishing gear, usually nets or traps that have been lost at sea.
Imported: Species imported from wild fisheries and aquaculture enterprises operating outside Australia, e.g. hoki from New Zealand, prawns from Southeast Asia.
Introduced: Species introduced into Australia’s marine environment deliberately for aquaculture production or stocking programs, e.g. Trout, Atlantic Salmon.
Keystone species: A species that has a major influence on the structure or functioning of an ecosystem. Its presence affects many other members of the ecosystem and, if its population dwindles or disappears, there can be far reaching consequences for the ecosystem, e.g. sharks.
Logbooks: The main way that fishers record their catch and interactions with endangered and protected wildlife. Fishery managers can verify reporting in logbooks is correct in conjunction with Electronic Monitoring.
Maximum Economic Yield: The sustainable catch level for a commercial fishery that allows the most profitable fishing. This usually involves lower fishing pressure, leaving ‘more fish in the water’, than Maximum Sustainable Yield.
Maximum Sustainable Yield: The maximum average annual catch that can be removed from a stock over an indefinite period under prevailing environmental conditions.
Observers: Observers are individuals on board fishing boats who are independent of the government and the fishing industry. Their job is to record information about the fishery operation, including interactions with threatened, endangered or vulnerable wildlife. Their reports provide credible records of fisheries impacts on marine wildlife. Observer programs are an essential component of good fisheries management.
Overfished: A stock is overfished when it has been depleted below a defined acceptable level. Management actions need to be taken to rebuild the stock to a healthy level.
Recruitment overfished: Overfishing has reduced the population to a level where recruitment (the number of larval fish added to the stock) is significantly suppressed. The result may be stock collapse if overfishing is prolonged and combined with poor environmental conditions.
Stock assessment: A scientific review of available data relating to a fished species stock that is used to estimate the health of a fish stock and set an appropriate level of fishing. Because fish populations, environment and fishing activity constantly changes, a stock assessment loses reliability as it ages, and does so more rapidly for fast growing fish species in dynamic ecosystems.
Growth overfished: Too many small fish are caught. Reducing catches and/or increasing the size at which fish are caught would help rebuild the fishery. A growth overfished stock can have negative knock-on impacts on the ecosystem as a whole.
Overfishing: The level of fishing pressure is too high and fish are being removed at a rate which is unsustainable. Continued overfishing will lead to an overfished stock (see above).
Seafood: Any fish or shellfish species caught or farmed for human consumption.
Sustainable fisheries: Fisheries are ecologically sustainable when the stocks of target species, non-target species and their surrounding ecosystems are maintained over the long-term. A truly sustainable fishery meets the long-term needs of fishermen, seafood consumers and the environment together.
Stock: A section of a species from which catches are taken in a fishery. It generally means that the population of a species that is being fished is more of less isolated from other stocks of the same species.
Target species: The fish or shellfish species that are the primary or intended catch of a particular fishery. Often the most highly sought and most valuable species are selected or targeted for fishing.
Threatened, endangered or protected species: Marine wildlife listed as threatened with extinction under Australian national laws, protected under those laws, or assessed as endangered by international authorities such as on the IUCN Red List.
Wild fisheries: See ‘capture fisheries’.