Extended Operational and Trade Vocabulary

Marine Biology, Fisheries and Oceanography glossary

The biological and oceanographic vocabulary of the sea: ocean depth zones (abyssal, abyssopelagic), named taxa such as the crown-of-thorns starfish and calanoid copepods, plankton and productivity, acidification, and the physical setting of the abyssal plain. The species-and-ecology counterpart to the physical oceanography section, grounded in named organisms and water-column structure.

722 defined terms.

Showing 250 on this page (page 1 of 3).

A

Abyssal Plain: Flat region of the deep ocean floor, typically below 4,000 meters.
Abyssopelagic zone: Open-ocean water column from about 4,000 to 6,000 m depth, perpetually dark and cold.
Acanthaster planci: Crown-of-thorns starfish, a coral-eating sea star that causes major reef outbreaks in the Indo-Pacific.
Acartia tonsa: Cosmopolitan calanoid copepod common in estuarine and coastal zooplankton.
Acidification: Decrease in seawater pH driven primarily by uptake of atmospheric carbon dioxide.
Acoustic Doppler Current Profiler (ADCP): Instrument that measures water current velocities over a depth range using the Doppler effect.
Acoustic release: Mooring component that frees a subsurface package on receipt of a coded sonar signal.
Adriatic Sea: Arm of the Mediterranean between Italy and the Balkan Peninsula.
Aegean Sea: Embayment of the Mediterranean between Greece and Turkey.
Agulhas Current: Strong western boundary current of the southwest Indian Ocean off the east coast of Africa.
Agulhas Retroflection: Region where the Agulhas Current turns back on itself south of Africa, shedding rings into the Atlantic.
Alaska Pollock: Gadoid groundfish *Gadus chalcogrammus*, supporting one of the world's largest single-species fisheries.
Albacore: *Thunnus alalunga*, a temperate tuna prized for canning.
Albatross: Large pelagic seabird of the family Diomedeidae, mostly in the Southern Ocean and North Pacific.
Alkalinity: Capacity of seawater to neutralize acid, a key parameter of the carbonate system.
Alvin (DSV Alvin): U.S. Navy-owned, WHOI-operated three-person deep-submergence research submersible.
American lobster: *Homarus americanus*, the principal commercial lobster of the northwest Atlantic.
Ammonia (NH3 / NH4+): Dissolved nitrogen compound; a primary excretion product of marine animals and a phytoplankton nutrient.
AMO: Atlantic Multidecadal Oscillation, a multi-decade pattern in North Atlantic sea surface temperatures.
AMOC: Atlantic Meridional Overturning Circulation, the large-scale overturning circulation of the Atlantic.
Amphidromic Point: Location where tidal amplitude is zero and tidal phase rotates around it.
Anadromous: Life history in which fish spawn in fresh water but mature at sea, as in salmon.
Anchoveta: *Engraulis ringens*, the Peruvian anchovy, target of the largest single-species fishery in tonnage.
Anchovy: Small pelagic schooling fish of the family Engraulidae.
Angler fish: Deep-sea fish of order Lophiiformes that use a bioluminescent lure (esca).
Anoxic: Containing no dissolved oxygen.
Antarctic Bottom Water (AABW): Dense, cold water mass formed around Antarctica that fills the deep global ocean.
Antarctic Circumpolar Current (ACC): World's largest ocean current, flowing eastward around Antarctica.
Antarctic Convergence: Frontal zone where cold Antarctic surface water meets warmer subantarctic water.
Antarctic krill: *Euphausia superba*, a keystone Southern Ocean species and major fishery resource.
Aphotic zone: Depth range where sunlight is too weak to support photosynthesis.
Aquaculture: Farming of aquatic organisms.
Arabian Sea: Northwestern arm of the Indian Ocean bordered by India, Pakistan, Iran, Oman, and Yemen.
Arafura Sea: Shallow shelf sea between northern Australia and New Guinea.
Archaea: Single-celled microorganisms, distinct from bacteria, abundant in the deep sea and in extreme environments.
Arctic cod: *Boreogadus saida*, a small gadid keystone species of Arctic food webs.
Argo Program: International array of profiling floats measuring temperature, salinity, and biogeochemistry of the upper 2,000 meters.
Aspect ratio (of a fin): Ratio of fin span squared to area; high values typify fast-cruising pelagic fishes.
Atlantic bluefin tuna: *Thunnus thynnus*, a large highly migratory pelagic managed by ICCAT.
Atlantic cod: *Gadus morhua*, a North Atlantic gadid historically central to Newfoundland and North Sea fisheries.
Atlantic herring: *Clupea harengus*, a key forage fish of the North Atlantic.
Atlantic salmon: *Salmo salar*, anadromous salmonid of the North Atlantic; also extensively farmed.
Atoll: Ring-shaped coral reef enclosing a lagoon, often surrounding a subsided volcanic island.
Auklet: Small diving seabird of the family Alcidae found in the North Pacific.
Aurelia aurita: Moon jellyfish, a cosmopolitan coastal scyphozoan.
Autotroph: Organism that synthesizes organic matter from inorganic carbon using light or chemical energy.
AUV: Autonomous Underwater Vehicle.
Azores Current: Eastward warm current branching from the Gulf Stream system into the eastern North Atlantic.

B

Baffin Bay: Body of water between Greenland and Baffin Island connected to the Labrador Sea.
Baikal seal: *Pusa sibirica*, the only exclusively freshwater pinniped, endemic to Lake Baikal.
Balaenoptera: Genus of rorquals including blue, fin, sei, Bryde's, and minke whales.
Baleen whale: Member of the suborder Mysticeti, filter feeders using keratin baleen plates.
Baltic Sea: Brackish marginal sea of the North Atlantic in northern Europe.
Banda Sea: Deep sea in eastern Indonesia within the Coral Triangle.
Barents Sea: Shelf sea of the Arctic Ocean north of Norway and Russia.
Barotropic / Baroclinic: Flow regimes where density surfaces parallel pressure surfaces (barotropic) or cross them (baroclinic).
Barrier reef: Coral reef separated from shore by a lagoon, such as Australia's Great Barrier Reef.
Bathymetry: Measurement and mapping of seafloor depth.
Bathypelagic zone: Open-ocean water column from about 1,000 to 4,000 m depth.
Bathythermograph: Expendable probe (XBT) measuring temperature profile versus depth from a moving ship.
Bay of Bengal: Northeastern arm of the Indian Ocean east of India.
Bay of Biscay: Gulf of the North Atlantic along the western coast of France and northern Spain.
Beam Trawl: Fishing net held open by a rigid beam.
Beaufort scale: Empirical wind force scale 0-12.
Beluga whale: *Delphinapterus leucas*, a small white toothed whale of Arctic and subarctic waters.
Bend (seafloor): Localised topographic feature; in oceanography also refers to meander curvature in currents.
Benguela Current: Cold eastern boundary current along the southwest coast of Africa.
Benthic: Pertaining to the seafloor or organisms living on or in it.
Benthos: Community of organisms living on, in, or near the seabed.
Bering Sea: Marginal sea between Alaska and Siberia, hosting major pollock and crab fisheries.
Bering Strait: Narrow passage connecting the Pacific and the Arctic Ocean between Russia and Alaska.
Bigeye tuna: *Thunnus obesus*, a tropical and subtropical tuna species.
Biofouling: Accumulation of organisms on submerged surfaces.
Biogeochemistry: Study of cycling of elements through biological, geological, and chemical processes.
Biological pump: Set of processes that transfer carbon from surface waters to the deep ocean via sinking organic matter.
Bioluminescence: Light produced by living organisms, common in marine plankton and deep-sea fauna.
Biomass: Total mass of living organisms in a given area or volume.
Bivalve: Mollusk with two hinged shells, including mussels, oysters, clams, and scallops.
Black Sea: Inland brackish sea between southeastern Europe and Asia Minor, anoxic below ~150 m.
Bligh Reef: Marine feature in Prince William Sound where Exxon Valdez ran aground in 1989.
Bloom: Rapid increase in plankton biomass, especially of phytoplankton.
Blue Economy: Sustainable use of ocean resources for economic growth.
Blue marlin: *Makaira nigricans*, a large pelagic billfish.
Blue mussel: *Mytilus edulis*, a widely farmed temperate bivalve.
Blue shark: *Prionace glauca*, an oceanic pelagic shark.
Blue whale: *Balaenoptera musculus*, the largest animal on Earth.
Bluefin tuna: Common name for three species (Atlantic, Pacific, southern) of large *Thunnus*.
Bohai Sea: Innermost gulf of the Yellow Sea on the north coast of China.
Bongo net: Paired plankton nets on a single frame used to collect quantitative zooplankton samples.
Bonito: Medium-sized tuna-like fishes of the genus *Sarda*.
Boreal: Pertaining to high-latitude northern temperate regions.
Bottom trawl: Towed conical net fished in contact with the seabed for demersal species.
Bowhead whale: *Balaena mysticetus*, a large Arctic baleen whale.
Brackish water: Water with salinity between fresh water and seawater, roughly 0.5 to 30 PSU.
Branchiostegite: Outer wall of the gill chamber in crustaceans.
Bream: Common name for various sparid and cyprinid fishes.
Bristlemouth: Small mesopelagic fish of the genus *Cyclothone*, one of the most abundant vertebrates on Earth.
Brittle star: Echinoderm of the class Ophiuroidea with slender, flexible arms.
Brown algae: Large group of multicellular marine algae (Phaeophyceae) including kelps and rockweeds.
Brown shrimp: *Crangon crangon* in Europe; *Farfantepenaeus aztecus* in the Gulf of Mexico.
Bryde's whale: *Balaenoptera edeni / brydei*, a tropical and subtropical rorqual.
Buoyancy frequency (N): Brunt-Väisälä frequency describing oscillation of a displaced fluid parcel in a stratified ocean.
By-Catch: Unintended catch of non-target species during fishing.

C

Calanus finmarchicus: Large copepod, dominant zooplankton biomass in the North Atlantic and key prey of right whales and herring.
Calcite compensation depth (CCD): Depth below which calcium carbonate dissolves faster than it accumulates.
California Current: Cold eastern boundary current of the North Pacific along western North America.
Cape Cod: Sandy peninsula in Massachusetts marking a major biogeographic boundary on the U.S. east coast.
Capelin: *Mallotus villosus*, a small forage fish of the North Atlantic and Arctic.
Carbon dioxide partial pressure (pCO2): Partial pressure of CO2 in seawater controlling air-sea CO2 exchange.
Caribbean Sea: Tropical sea bordered by Central America, South America, and the Antilles.
Carrying capacity: Maximum cargo a vessel can carry, in deadweight or volume.
Caspian Sea: World's largest enclosed inland body of water, between Europe and Asia.
Catadromous: Life history in which fish mature in fresh water but spawn at sea, as in *Anguilla* eels.
Catch Per Unit Effort (CPUE): Catch divided by fishing effort, used as a relative abundance index.
CCAMLR: Commission for the Conservation of Antarctic Marine Living Resources.
CCSBT: Commission for the Conservation of Southern Bluefin Tuna.
Celebes Sea: Western Pacific marginal sea in the Coral Triangle.
Celtic Sea: Atlantic shelf sea south of Ireland and west of Brittany.
Cetacean: Marine mammal of the infraorder Cetacea (whales, dolphins, porpoises).
Chaetoceros: Diverse genus of marine planktonic diatoms.
Chart datum (CD): Reference for sounding depths, usually LAT.
Chemoautotroph: Organism using chemical energy to fix inorganic carbon, important at hydrothermal vents.
Chesapeake Bay: Large U.S. east-coast estuary in Maryland and Virginia.
Chinook salmon: *Oncorhynchus tshawytscha*, the largest Pacific salmon species.
Chlorinity: Mass of chloride per kilogram of seawater, historically used to estimate salinity.
Chlorophyll-a: Pigment in phytoplankton commonly measured to estimate ocean primary productivity.
Chondrichthyes: Class of cartilaginous fishes including sharks, rays, and chimaeras.
Chukchi Sea: Marginal sea of the Arctic Ocean north of the Bering Strait.
Ciguatera: Tropical fish poisoning from ciguatoxins originating in the dinoflagellate *Gambierdiscus*.
Clam: Burrowing bivalve mollusk; commercial species include hard clams, soft-shells, and geoducks.
Climate Velocity: Speed and direction at which species must move to track shifting isotherms.
Closed area: Defined zone where specified fishing activities are prohibited.
Coastal Upwelling: Wind-driven uplift of cold, nutrient-rich water along a coastline.
Coccolithophore: Single-celled marine alga that produces calcium carbonate plates (coccoliths).
Cod: Common name for gadid fishes, especially *Gadus morhua* (Atlantic) and *Gadus macrocephalus* (Pacific).
Cold seep: Seafloor area where reduced fluids (methane, sulfide) seep out, supporting chemosynthetic communities.
Common dolphin: *Delphinus delphis*, a widely distributed small cetacean.
Compensation depth: Depth at which photosynthesis equals respiration in a phytoplankter.
Conductivity: Electrical conductivity of seawater, used in the CTD to derive salinity.
Continental Margin: Zone between continental crust and ocean basin, including shelf, slope, and rise.
Continental Shelf: Seabed and subsoil beyond territorial sea, up to the outer edge of the continental margin or 200 nm.
Continuous Plankton Recorder (CPR): Towed plankton sampler operated since 1931, providing long time-series data.
Convection (deep): Vertical mixing reaching great depth, important in formation of deep water masses.
Convergence Zone: Region where surface currents or air streams flow together, often producing fronts.
Copepod: Small crustacean of the subclass Copepoda; the most abundant metazoans in the ocean.
Coral Bleaching: Loss of symbiotic algae from corals under thermal stress.
Coral reef: Calcareous biogenic structure built by scleractinian corals and supporting high biodiversity.
Coral Triangle: Indo-Pacific region of highest marine biodiversity covering parts of Indonesia, Philippines, Malaysia, PNG, Solomon Islands, and Timor-Leste.
Coriolis effect: Apparent deflection of moving objects due to Earth's rotation; right in N, left in S hemisphere.
Cormorant: Coastal diving seabird of the family Phalacrocoracidae.
Cownose ray: *Rhinoptera bonasus*, a schooling estuarine ray of the western Atlantic.
Crab pot: Baited trap used to catch crabs.
Crinoid: Echinoderm of the class Crinoidea, including sea lilies and feather stars.
Crown-of-thorns starfish: *Acanthaster planci*, a coral predator of Indo-Pacific reefs.
Crustacean: Member of the subphylum Crustacea, including crabs, lobsters, shrimp, copepods, and krill.
CTD: Conductivity-Temperature-Depth instrument, the standard hydrographic profiler.
Ctenophore: Comb jelly, gelatinous predator of the phylum Ctenophora.
Cusk: *Brosme brosme*, a deep-water gadid of the North Atlantic.
Cyanobacteria: Photosynthetic bacteria including *Prochlorococcus*, *Synechococcus*, and *Trichodesmium*.
Cyclone: Low-pressure rotating storm system; in tropics called a typhoon or hurricane depending on basin.

D

Dab: Small flatfish (*Limanda limanda*) of European waters.
Dahomey Gap: Coastal interruption of West African rainforest; analog used in marine biogeographic discussion.
Dall's porpoise: *Phocoenoides dalli*, a fast-swimming North Pacific porpoise.
Danish seine: Active demersal gear similar to a small trawl, towed along the seabed in a closing arc.
Davis Strait: Strait between Greenland and Baffin Island.
Decapod: Crustacean order Decapoda, including shrimp, lobsters, crayfish, and crabs.
Deep scattering layer (DSL): Sound-reflecting layer in the mesopelagic, formed by mesopelagic fish and invertebrates that vertically migrate diurnally.
Deep Western Boundary Current (DWBC): Equatorward flow of North Atlantic Deep Water along the western Atlantic.
Demersal: Living near, but not strictly on, the seabed.
Demersal Fish: Fish living on or near the seabed.
Density anomaly (sigma-t): Seawater density at one atmosphere minus 1,000 kg/m3, in kg/m3.
Desorption: Release of adsorbed substances from a surface; relevant in particle-trace metal cycling.
Detritivore: Organism feeding on detritus (decomposing organic matter).
Diadromous: Fish that migrate between fresh and salt water.
Diatom: Single-celled alga with silica frustule, dominant primary producer in productive seas.
Dinoflagellate: Single-celled, often flagellated protist; many cause harmful algal blooms.
Discards: Portion of catch returned to the sea, often dead.
Dissolved Inorganic Carbon (DIC): Sum of CO2, bicarbonate, and carbonate ions dissolved in seawater.
Dissolved Organic Carbon (DOC): Operationally defined fraction of organic carbon passing through a filter.
Dissolved Oxygen (DO): Concentration of O2 in seawater, vital for marine respiration.
Diurnal Tide: Tide with one high and one low water per tidal day.
DMS (dimethyl sulfide): Sulfur compound produced from phytoplankton metabolism, influencing marine aerosols.
Dolphin: Isolated marine structure.
Dolphin-safe: Tuna-fishery certification indicating measures to avoid harming dolphins, especially in the ETP.
Doppler shift: Frequency change of sound due to relative motion; used by ADCPs to measure current speed.
Doxorubicin (marine origin): Anticancer drug derived from *Streptomyces peucetius*; sometimes cited in marine natural products.
Drake Passage: Strait between South America and Antarctica through which the ACC flows.
Dredge: Towed bottom gear with a rigid frame and bag, used for scallops, oysters, and mussels.
Drifter: Surface or subsurface device that follows currents to measure Lagrangian flow.
Dugong: *Dugong dugon*, a seagrass-grazing sirenian of the Indo-Pacific.
Dungeness crab: *Metacarcinus magister*, an important North Pacific commercial crab.

E

East Australian Current: Warm western boundary current of the South Pacific along eastern Australia.
East China Sea: Marginal sea of the Pacific bordered by China, Korea, Japan, and Taiwan.
East Greenland Current: Cold southward current carrying Arctic water along Greenland's east coast.
Eastern Pacific Ocean (EPO): Region east of 150 deg W; key tuna fishery area managed by IATTC.
Echinoderm: Marine invertebrate of the phylum Echinodermata (sea stars, urchins, holothurians, etc.).
Echo sounder: Acoustic depth sensor.
Ecological footprint (fishing): Area of productive ecosystem needed to sustain a fishery's catches.
Ecosystem approach to fisheries (EAF): Management framework integrating ecological, social, and economic objectives.
Eddy: Circular movement of water counter to the main current.
Eel: Snake-like fish of the order Anguilliformes; *Anguilla anguilla* and *Anguilla rostrata* are catadromous.
EEZ: Exclusive Economic Zone, up to 200 nm under UNCLOS Part V.
Effort (fishing): Quantitative measure of fishing activity, often expressed as days at sea or hook-hours.
Ekman Layer: Surface or bottom layer where wind or bottom friction transfers momentum.
Ekman Pumping: Vertical motion driven by divergence or convergence of Ekman transport.
Ekman Spiral: Theoretical wind-driven current that rotates with depth due to Coriolis force.
Ekman Transport: Net horizontal mass transport in the Ekman layer, perpendicular to wind direction.
El Nino: Warm phase of ENSO with weakened trade winds and warming of the eastern tropical Pacific.
Elasmobranch: Subclass of cartilaginous fishes including sharks, skates, and rays.
Endemic species: Species restricted to a particular geographic region.
English Channel: Arm of the Atlantic Ocean between southern England and northern France.
ENSO: El Nino-Southern Oscillation, the dominant interannual coupled ocean-atmosphere mode in the tropical Pacific.
Epibenthos: Organisms living on the surface of the seabed.
Epifauna: Animals living attached to or on the seabed surface.
Epipelagic zone: Sunlit surface layer of the open ocean, typically 0 to 200 m.
Equatorial Undercurrent (EUC): Subsurface eastward current along the equator in the Pacific and Atlantic.
Estuary: Semi-enclosed coastal body of water where freshwater meets seawater.
Eulerian Measurement: Observation at a fixed point in space, such as a moored current meter.
Euphausia superba: Antarctic krill, a keystone Southern Ocean species.
Euphausiid: Krill, shrimp-like crustaceans of the order Euphausiacea.
Euphotic zone: Upper sunlit layer of the water column where net photosynthesis is possible.
Eutrophication: Nutrient enrichment leading to excessive plant or algal growth.
Exclusive Economic Zone (EEZ): 200 nm zone of coastal state sovereign rights over resources.
Exuvia: Cast-off exoskeleton of an arthropod after molting.

F

F (fishing mortality): Instantaneous rate at which fish are removed by fishing.
FAD (Fish Aggregating Device): Floating object used to concentrate pelagic fish.
FAO: Food and Agriculture Organization of the United Nations.
FAO Major Fishing Area: Statistical area for global catch reporting.
Faroe Islands: North Atlantic archipelago and self-governing nation within the Kingdom of Denmark.
Fecundity: Number of eggs produced per female per spawning event.
Fetch: Distance over water across which the wind blows generating waves.
Fiji Sea: Region of the South Pacific around the Fijian archipelago.
Filter feeder: Organism that strains suspended particles from water (e.g., baleen whales, mussels, copepods).
Fin whale: *Balaenoptera physalus*, the second-largest animal on Earth.
First-Year Ice: Sea ice that has not survived a melt season.
Fish meal: Dried, ground product made from whole fish or fish trimmings, used in feeds.
Fish oil: Oil extracted from oily fish such as anchoveta and menhaden.
Fishing capacity: Maximum catch a fleet can produce given current technology and inputs.
Flag of convenience: Flag of a state with open registration policy.
Flag State: State of the ship's nationality, with jurisdiction under UNCLOS Article 94.
Flatback turtle: *Natator depressus*, sea turtle endemic to the Australian continental shelf.
Flatfish: Fish of the order Pleuronectiformes, including flounder, sole, halibut, and turbot.
Florida Current: Warm current flowing northward through the Straits of Florida, feeding the Gulf Stream.
FMSY: Fishing mortality producing MSY.
Food web: Network of feeding relationships in an ecosystem.
Foraminifera: Single-celled protists with calcareous tests; key proxies in paleoceanography.
Fram Strait: Passage between Greenland and Svalbard, the main deep connection between Arctic and Atlantic.
Freak wave: See Rogue wave.
Front (oceanographic): Narrow zone of strong horizontal property gradients between water masses.
Frustule: Silica cell wall of a diatom.