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Protected Resources Glossary

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For more terms related to all of NOAA Fisheries, please refer to the NOAA Fisheries Glossary [pdf] [1.7 MB].


Adipose Fin: a fin without a bone or cartilage, located behind the dorsal fin

Anadromous: Species that live their adult lives in the ocean but move into freshwater streams to reproduce or spawn (e.g., salmon).

Animal and Plant Health Inspection Service (APHIS): Part of the U.S. Department of Agriculture (USDA) that is charged with regulating the treatment of marine mammals held in captivity. APHIS creates health standards such as tank size and water quality.

Animal Welfare Act (AWA): Federal statute (7 U.S.C. 2131 eq sep.) created in 1966, to--

Antarctic Convergence: a line encircling Antarctica where cold, northward-flowing Antarctic waters sink beneath the relatively warmer waters of the sub-Antarctic. The convergence is a dynamic boundary, meaning it's precise location may shift, but is generally located between 48º S and 61º S latitude

Applicant/Holder: Person, institution, or agency who is ultimately responsible for all activities of any individual who is operating under the authority of a permit.

Arctic waters: Marine and estuarine waters north of 60° N. latitude.

Arribada: the Spanish word for "arrival"; massive synchronized nesting within the genus Lepidochelys


Baleen: Long, flat plates made of fingernail-like material called keratin that hang from a baleen whale's mouth in place of teeth.

Barbel: A fleshy sensory appendage, often arising from the head or chin area of a fish (e.g., catfish "whiskers").

Bathypelagic: ocean depths between about 2,000-12,000 feet (600-3,600 m)

Benthic: anything associated with or occuring on the bottom of a body of water

Benthopelagic: occurring on the bottom or midwaters of a body of water

Biological Opinion: Under ESA section 7, all Federal agencies are required, "in consultation with and with the assistance of the Secretary, to insure that any action authorized, funded, or carried out by such agency is not likely to jeopardize the continued existence of any threatened or endangered species or result in the destruction or adverse modification of designated critical habitat."
Thus, before a permit can be issued, "a written statement setting forth the Secretary's opinion and a summary of the information on which the opinion is based" that the issuance of the permit is not likely to jeopardize any protected species must be obtained.

Blackfish: a non-taxonomic grouping of predominantly small, dark cetaceans (e.g., pilot whales)

Bona fide scientific research: Scientific research conducted by qualified personnel, the results of which--

Boreal: of or pertaining to the north, north wind, or northern type of forest.

Bow riding: swimming near the front part of a ship

Brackish: Pertaining to waters with a salt concentration between that of pure ocean water and freshwater (i.e., bay water).

Breach: to leap out of water

Bycatch: Animals caught by fishing that were not the intended target of the fishing activity. Such unwanted catch is often wasted.


Candidate Species: any species that is undergoing a status review that NMFS has announced in a Federal Register notice. Thus, any species being considered by the Secretary (of the Department of Commerce or Interior) for listing under the ESA as an endangered or a threatened species, but not yet the subject of a proposed rule (see 50 CFR 424.02). NMFS' candidate species also qualify asspecies of concern. "Candidate species" specifically refers to--

For detailed definitions and explanations of Candidate Species, please refer to the April 15, 2004 and October 17, 2006, Federal register notices--(69 FR 19975) [pdf] and (71 FR 61022) [pdf]--that revised the Candidate Species definition.

Carrying Capacity: The maximum number of animals an environment can support based on the available resources.

Catch Per Unit Effort (CPUE): A measure of the density or population size of an animal that is targeted by fishing. Large CPUEs indicate large populations since many individuals are caught for every unit of fishing effort.

Caudal Peduncle: the portion of a cetacean's body between the dorsal fin and the fluke (tail). See also: tailstock

Code of Federal Regulations (CFR): Regulations created by various Federal agencies to support and explain Federal statutes. For purposes of this document, USFWS and NMFS have created wildlife and fisheries regulations to support and clarify sections of the MMPA and ESA. The wildlife and fisheries regulations pertaining to marine mammals and endangered species can be found in 50 CFR 1 - 599.

Co-investigator (CI): The on-site representative(s) of the Primary Investigator (PI) who conducts or directly supervises the conduct of the taking, importing, and exporting activities authorized under the permit.

Critical habitat:

  1. Specific areas within the geographical area occupied by the species at the time of listing, if they contain physical or biological features essential to conservation, and those features may require special management considerations or protection; and
  2. Specific areas outside the geographical area occupied by the species if the agency determines that the area itself is essential for conservation.
    » Critical Habitat maps


Delisted: When a species is no longer listed under the ESA. See also Recovered Species.
» Delisted species

Depleted: Defined by the MMPA as any case in which--

Diatoms: minute planktonic unicellular or colonial algae

Dimorphism (sexual): males and females appear visually different

Distinct Population Segment (DPS): A DPS, or a distinct population segment, is a vertebrate population or group of populations that is discrete from other populations of the species and significant in relation to the entire species. The ESA provides for listing species, subspecies, or distinct population segments of vertebrate species.

Dorsal: relating to or situated near or on the back


Elasmobranch: Elasmobranchii is the subclass of cartilaginous (with skeleton made of cartilage rather than bone) fishes (class chondrichthyes) that includes skates, rays and sharks. Elasmobranchs have an upper jaw that is not fused to the braincase and separate slitted gill openings.

Endangered: Defined under the ESA as "any species which is in danger of extinction throughout all or a significant portion of its range."
» Endangered species

Endemic: Native to a certain area, usually a relatively small area.

Endothermic: Animals that generate body heat above ambient temperatures through various physiological and anatomical specializations.

Enhancement permits: As defined in the MMPA, they are, "permits issued for the recovery of a species or stock where taking or importation--

Epipelagic: waters from the surface to depths generally not exceeding around 650 feet (200 m).

Estuary: A semi-encolsed body of water having connections to the ocean at the downstream end and freshwater streams at the upstream end. Water in estuaries thus tends to be at an intermediate and variable salinity and temperature

Euryhaline: Tolerant to a wide-range of salinities.

Evolutionarily Significant Unit (ESU): An ESU, or evolutionarily significant unit, is a Pacific salmon population or group of populations that is substantially reproductively isolated from other conspecific populations and that represents an important component of the evolutionary legacy of the species. The ESU policy [pdf] (56 FR 58612) for Pacific salmon defines the criteria for identifying a Pacific salmon population as a distinct population segment (DPS), which can be listed under the ESA.

Exclusive Economic Zone (EEZ): In the U.S., the EEZ extends up to 200 nautical miles from the coastline. Presidential Proclamation 5030 created the Exclusive Economic Zone in 1983.

Extirpate: to remove or destroy totally.


Falcate: hooked, curved, sickel-shaped; often referring to the shape of a dorsal fin.

Fall Line: A line connecting the waterfalls of nearly parallel rivers that marks a drop in land level.

Fecundity: the potential reproductive capacity of an organism or population, measured by the number of gametes (eggs)

Flipper Slapping: Flipper or fluke slapping is when a cetacean slaps the water with its flipper or fluke. This action sometimes creates a very loud sound that has been described as sounding like a gun shot.

Fluke: the tail of a whale

Fluking: When the fluke (tail) is raised vertically out of the water

Foot: in gastropod mollusks, such as black abalone, the foot is a muscular appendage used for movement and adhering to substrates

Foreign Species: Foreign species are those that occur entirely outside of U.S. territory. NMFS cannot designate critical habitat in foreign waters.

Forage: to wander in search of food

Fork Length: measurement from the tip of the snout to the fork of the tail.
Fork length - total length comparison.

Founder Effect: When a population is very small after the movement of some individuals to a new area that is unoccupied, the genetic makeup of that new group will differ from the makeup of their original source area just by random chance depending on the genetic structure of the founding individuals.


Gametes: eggs and sperm

Gene Flow: The movement of genes from one population to the other through movement of individuals between those populations.


Harassment: Under the 1994 Amendments to the MMPA, harassment is statutorily defined as, any act of pursuit, torment, or annoyance which--

Haul Out: the place or the act of an animal crawling or pulling themselves out of the water and onto land, ice, or other object, such as a buoy


Import: to land on, bring into, or introduce into, or attempt to land on, bring into, or introduce into, any place subject to the jurisdiction of the United States, whether or not such landing, bringing, or introduction constitutes an importation within the Customs Laws of the U.S., except that, for the purpose of any ban issued under 16 U.S.C. 1371(a)(2) on the importation of fish or fish products, the definition of "import" in 50 CFR §216.24(e)(1)(ii) shall apply.

Incidental Taking: An unintentional, but not unexpected, taking.

Intrusive Research: a procedure conducted for bona fide scientific research involving:

For captive animals, this definition does not include:

  1. A procedure conducted by the professional staff of the holding facility or an attending veterinarian for purposes of animal husbandry, care, maintenance, or treatment, or a routine medical procedure that, in the reasonable judgment of the attending veterinarian, would not constitute a risk to the health or welfare of the captive animal; or
  2. A procedure involving either the introduction of a substance or object (i.e., as described in this definition) or a stimulus directed at animals that, in the reasonable judgment of the attending veterinarian, would not involve a risk to the health or welfare of the captive animal.


Keel: a deepening or thickening of the body, particularly near the tail of some cetaceans.


Lobtailing: when a cetacean lifts its fluke (tail) out of the water and slaps it on the surface of the water

Lanugo: the thick fur of a pinniped shed after birth

Logging: floating motionless


Mantle: as in mollusks, such as the black abalone, the mantle is a thin layer of tissue that covers most of the organs and produces the shell

Marine Mammal Commission: A three-member panel appointed by the President to oversee implementation of the MMPA, and provide scientific advice to the Secretaries of Commerce and Interior. All permit applications for scientific research must be reviewed by the Commission and its 10-member Committee of Scientific Advisors on Marine Mammals.

Maximum Sustainable Yield (MSY): The long-term yield of fish to a fishery that can be sustained indefinitely.

Melon: the often bulging, fatty forehead of a toothed cetacean

Mesopelagic: ocean depths extending from 200 m (650 ft.) down to around 1000 m (3280 ft.) below sea level

Minimum Population Estimate: Defined by the MMPA as an estimate of the number of animals in a stock that--

Molt: the process of shedding hair, skin, or an outer layer periodically to be later replaced by new growth

Morbillivirus: A highly contagious and lethal genus of virus (Family Paramyxoviridae) that has been responsible for more significant marine mammal die-offs due to infectious disease than any other pathogen to date.

Mottling: spots or blotches of different color or shades of color, as if stained

Myctophids: small, deep sea fish found worldwide. They are also known as lanternfishes, named for their ability to emit light


Natal: Pertaining to birth, usually in the context of animals that return to their place of birth to spawn or give birth themselves (e.g., many salmon).

Negligible Impact: An impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.

Neritic Zone: nearshore area


Optimum Sustainable Population: defined by the MMPA section 3(9), with respect to any population stock, the number of animals which will result in the maximum productivity of the population or the species, keeping in mind the carrying capacity of the habitat and the health of the ecosystem of which they form a constituent element. (16 U.S.C. 1362(3)(9))

Optimum Sustainable Population is further defined by Federal regulations (50 CFR 216.3) as is a population size which falls within a range from the population level of a given species or stock which is the largest supportable within the ecosystem to the population level that results in maximum net productivity. Maximum net productivity is the greatest net annual increment in population numbers or biomass resulting from additions to the population due to reproduction and/or growth less losses due to natural mortality.

Overfished:When the size of a fish stock is smaller than the sustainable target set by the National Marine Fisheries Service.

Overfishing: When a fish stock is being fished at a fishing mortality rate that exceeds the overfishing threshold set by the National Marine Fisheries Service.


Panmictic: Random mating of individuals within a population, the breeding individuals showing no tendency to choose partners with particular traits.

Parts: Hard parts are any bone, tooth, baleen, treated pelt, or other part of a marine mammal that are relatively solid or durable. Soft parts are any marine mammal part that is not a hard part (e.g. blood, muscle, blubber, skin, tissue-derived parts such as cell lines and DNA), excluding urine or fecal material.

Pectoral flippers: forelimbs of whales and dolphins that are used for stability and steering; they are generally flattened and paddle-like.

Pelagic: Pertaining to the part of the open sea or ocean comprising the water column, i.e., all of the sea other than that near the coast or the sea floor.

Pitch-pole: to turn end over end

Plan of Cooperation: Required where the proposed activity would take place in or near a traditional Arctic subsistence hunting area and/or may affect the availability of a species or stock of marine mammal for Arctic subsistence uses. The plan must include--

Plankton: Passively drifting or weakly swimming organisms that occur in swarms near the surface of open water

Polygamy: the tendency for one male to mate with two or more females

Porpoising: when an animal moves in and out of the water in a series of high speed leaps, much like a porpoise. Dolphins, whales, seals, and even penguins have been observed porpoising.

Potential Biological Removal (PBR) Level: defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population. The PBR level is the product of the following factors--

Principal Investigator (PI): The individual primarily responsible for the taking, importation, export, and any related activities conducted under a permit issued for scientific research or enhancement.

Proposed species: Those candidate species that were found to warrant listing as either threatened or endangered and were officially proposed as such in a Federal Register notice after the completion of a status review and consideration of other protective conservation measures. Public comment is always sought on a proposal to list species under the ESA. NMFS generally has one year after a species is proposed for listing under the ESA to make a final determination whether to list a species as threatened or endangered.

Pupping Season: The time of year that seals give birth.


Recovered Species: Under the ESA, a species is "recovered" when it is no longer requires protection under the ESA and thus is delisted. In practice, a species or stock is widely regarded as recovered only once it is delisted under both the ESA and the MMPA (i.e., it is no longer "depleted" under the MMPA).

Rehabilitation: treatment of beached and stranded marine mammals taken under MMPA section 109(h)(1) or imported under MMPA section 109(h)(2) with the intent of restoring a marine mammal's health and, if necessary, behavioral patterns.

Research Assistant (RA): Any individual working under the direct on-site supervision of the Principal Investigator (PI) and/or Co-Investigator (CI).

Recruitment: Time when a young fish enters a fishery (i.e., becomes large enough to be caught) or enters a specific habitat such as juvenile or adult habitat.

Rooster Tail: spray of water created as a porpoise or dolphin surfaces at high speed, especially characteristic of the Dall's porpoise

Rostrum: Any beaklike prolongation, especially of the head of an animal. In various marine mammals, the rostrum is commonly referred to as the "beak" or "snout."


Scutes: Horny plates or thorny scales, as on the shell of a sea turtle or body of a sturgeon, respectively.

Secretary: The MMPA establishes a Federal responsibility to conserve marine mammals, with management of all cetaceans and pinnipeds (except walrus) vested in the Department of Commerce (presided over by the Secretary of Commerce). The Department of the Interior (under the supervision of the Secretary of the Interior) is responsible for all other marine mammals, including sea otter, walrus, polar bear, manatee, and dugong.

Serious Injury: Any injury that will likely result in mortality (50 CFR 216.3).

Sill: submerged ridge or vertical wall of relatively shallow depth separating two bodies of water

Smoltification: a complex developmental transformation, involving physiological, biochemical, morphological, and behavioral changes, that allows young salmon (parr) to transition from living in freshwater to living in saltwater

Species: Depending on how they were listed under the ESA, species is defined as species, subspecies, distinct population segment (DPS), or Evolutionarily Significant Unit (ESU).

Species of Concern: species about which NMFS has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the ESA. This may include species for which NMFS has determined, following a biological status review, that listing under the ESA is "not warranted," pursuant to ESA section 4(b)(3)(B)(i), but for which significant concerns or uncertainties remain regarding their status and/or threats. Species can qualify as both "species of concern" and "candidate species."

Spermaceti Organ: an organ inside a sperm whale's head that, historically, whalers believed produced sperm, but actually contains high quality oil.

Spyhopping: When whales and dolphins raise their heads vertically out of the water.

Stock: As defined by the MMPA, the term "stock" means a group of marine mammals of the same species or smaller taxa in a common spatial arrangement, that interbreed when mature.

Stranded marine mammal: a marine mammal specimen under the jurisdiction of the Secretary (Secretary of Commerce or authorized representatives). The term "stranding" as defined in the MMPA means an event in the wild in which--

Strategic Stock: defined by the MMPA as a marine mammal stock--

Subsistence: The use of marine mammals taken by Alaskan Natives for food, clothing, shelter, heating, transportation, and other uses necessary to maintain the life of the taker or those who depend upon the taker to provide them with such subsistence.


Tailstock: the portion of a cetacean's body between the dorsal fin and the fluke (tail). See also: caudal peduncle


Thoracic: relating to the thorax, the part of a mammalian body between the neck and the abdomen

Threatened: Defined under the ESA as "any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range."
» Threatened species


Unmitigable Adverse Impact: An impact resulting from the specified activity that--


Vomer: bone in the roof of the mouth, may have teeth in some species, such as the Pacific eulachon


Whelping: giving birth

Updated: May 7, 2014