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Fisheries Glossary

agricultural runoff
water leaving areas of agricultural land use, usually enriched in nutrients, sediment, and agricultural chemicals.
algal bloom
the rapid excessive growth of algae, generally caused by high nutrient levels. Algal blooms can result in decreased oxygen in a body of water when the algae die, threatening the health of local marine life.
aquaculture
the cultivation of aquatic organisms (as fish or shellfish) especially for food; fish farming.
beam trawling
the simplest method of bottom trawling in which the mouth of the net is held open by a solid metal beam. The beam is attached to two "shoes" (solid metal plates), that are welded to the ends of the beam, and slide over and disturb the seabed. This method is mainly used on smaller vessels, fishing for flatfish or prawns, relatively close inshore.
billfish
fish with long, spear-like protrusions at their snouts, such as swordfish and marlin, that live near the upper layers of the ocean.
biodiversity
the number and variety of organisms found within a specified geographic region.
biomass
the total mass of living matter in a given environmental area.
bottom trawling
fishing method that involves towing trawl nets along the sea floor.
by-catch
unwanted marine creatures that are caught in the nets while fishing for another species.
cetacean
member of the group of marine mammals that includes whales, dolphins and porpoises.
climate
the weather in some location averaged over some long period of time.
climate change
variation in the Earth's global climate or in regional climates over time. Climate change involves changes in the variability or average state of the atmosphere over time periods ranging from decades to millions of years. These changes can be caused by natural processes on Earth, external factors including variations in sunlight intensity, and more recently by human activities.
climate variability
the way climatic variables (such as temperature and precipitation) depart from some average state, either above or below the average value, without significant changes to long-term averages.
collapse
significant depletion of a particular fish population, often cited as the point at which a population is down to 10 percent of previous levels.
dead zone
an area in an ocean or large lake where oxygen levels are extremely low, often due to the process of eutrophication. Observed incidences of dead zones have been steadily increasing since the 1970s.
demersal
living at or near the bottom of a body of water.
diadromous
fish that migrate between fresh and salt waters.
ecosystem
a community of living things and the environment in which they live.
ecosystem-based management (EBM)
approach to fisheries management that that integrates ecosystem impacts into the management of fisheries. Thus, habitat, predators, and prey of the target species, as well as other ecosystem components and interactions, are taken into account in managing fisheries. This approach both ensures that ecosystems will be sustained, and provides the foundation for long-term sustainability of fisheries.
ecosystem-based management (EBM) tool
software or another highly documented method that can help implement EBM by providing models of ecosystems or key ecosystem processes; generating scenarios illustrating the consequences of different management decisions on natural resources and the economy; or facilitating stakeholder involvement in planning processes.
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