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Stream Net - Fisheries management
Category: Agriculture and Industry > Fisheries Management
Date & country: 27/04/2012, US
Words: 903


Mandibular
Pertaining to the lower jaw.

Mark-recapture study
A study that estimates population size by marking a segment of the population at one time and later measuring the ratio of marked animals to total animals.

Masonry Dam
A dam constructed mainly of stone, brick, or concrete blocks that may or may not be joined with mortar. A dam having only a masonry facing should not be referred to as a masonry dam.

Mass marking
The marking of all individuals in a population of fish so that individuals can be identified in subsequent life history stages.

Mass movement
The downslope movement of earth caused by gravity. Includes but is not limited to landslides, rock falls, debris avalanches, and creep. It does not however, include surface erosion by running water. It may be caused by natural erosional processes, or by natural disturbances (e.g., earthquakes or fire events) or human disturbances (e.g., mining or road construction).

Maxillae or maxillaries
The upper jaw, the upper jaw bones.

Maximum Sustainable Yield
The largest average catch or yield that can continuously be taken from a stock under existing environmental conditions. (For species with fluctuating recruitment, the maximum might be obtained by taking fewer fish in some years than in others.) Also called; maximum equilibrium catch ; maximum sustained yield; sustainable catch.

Mean Seal Level (MSL)
A measure of elevation above sea level.

Mechanical bypass systems
See bypass system.

Megawatt-hour (MWh)
A unit of electrical energy equal to one megawatt or power applied for one hour.

Megawatts (MW)
A megawatt is one million watts or one thousand kilowatts, a measure of electrical power or generating capacity. A megawatt will typically serve about 1,000 people. The Dalles Dam produces an average of about 1,000 megawatts.

Mental
Pertaining to the chin or mentum.

Mesic
Moderately wet.

Meta-population
A population comprising local populations that are linked by migrants, allowing for recolonization of unoccupied habitat patches after local extinction events.

Mid-Columbia
The section of the Columbia River between the junction with the Snake River and Chief Joseph Dam.

Mid-Columbia Coordinating Committee
A committee whose primary purpose is to improve fish passage at the mid-Columbia dams. It determines annual operating requirements for fish passage at the dams; schedules research projects; and implements flow and spill requirements of the Mid-Columbia Settlement Agreement. The committee is composed of eight representatives of the fish and wildlife agencies, Indian tribes, the three mid-Columbia Public Utility Districts, and a power purchaser

Mid-Columbia dams
Dams owned by the mid-Columbia Public Utility Districts. They include Wells, Rocky Reach, Rock Island, Wanapum and Priest Rapids dams.

Migrant
Life stage of anadromous and resident fish species which moves from one locale, habitat or system (river or ocean) to another.

Migrating
Moving from one area of residence to another.

Milt
The sperm of fishes.

Minimum flow level
The level of stream flow sufficient to support fish and other aquatic life; to minimize pollution; or to maintain other instream uses such as recreation and navigation.

Minimum operating pool
The lowest water level of an impoundment at which navigation locks can still operate.

Minimum spanning tree
A means of depicting nearest genetic neighbors. The tree is an undirected network of smallest genetic distances between genetic samples superimposed on multidimensional scaling graphs to reveal local distortion (pairs of points which look close together in one dimension, but which are far apart in other dimensions).

Mitchell Act
The Mitchell Act of 1938 (Public Law No. 75-502, 16 U.S.C. 755), which authorizes federal funds for hatchery construction and operation within the Columbia River Basin.

Mitigating measures
Modifications of actions that (1) avoid impacts by not taking a certain action of parts of an action; (2) minimize impacts by limiting the degree or magnitude of the action and its implementation; (3) rectify impacts by repairing, rehabilitating, or restoring the affected environment; (4) reduce or eliminate impacts over time by preservation and maintenance operations during the life of the action; or (5) compensate for impacts by replacing or providing substitute resources or environments.

Mitigation
The act of alleviating or making less severe. Generally refers to efforts to alleviate the impacts of hydropower development to the Columbia Basins salmon and steelhead runs.

Mixed stock
A stock whose individuals originated from commingled native and non-native parents; or a previously native stock that has undergone substantial genetic alteration.

Mixed-stock fishery
A harvest management technique by which different species, strains, races or stocks are harvested together.

Monitor
To systematically and repeatedly measure conditions in order to track changes.

Monophyletic
Relating to, descended from, or derived from one stock or source.

Morphoedaphic index (MEI)
The most widely used index of potential fish production in lakes. A metric expression of the MEI is derived by dividing a lake's total dissolved solids (mg/L), or its conductivity, by its mean depth in meters.

Morphology
The structure, form and appearance of an organism.

Mortality
The number of fish lost or the rate of loss.

Multidimensional scaling
A nonmetric ordination technique used to visualize genetic relationships among populations in two or three dimensions. This technique requires that the distances between samples in two- or three-dimensional graphs have monotonic relationships to the original genetic distances between pairs of samples.

Myomeres
The muscle segments.

Natal
Birth place.

Natal stream
Stream of birth.

Native species
A species of fish indigenous to a specific state.

Native stock
An indigenous stock of fish that has not been substantially affected by genetic interactions with non-native stocks or by other factors, and is still present in all or part of its original range.

Natural fish
A fish that is produced by parents spawning in a stream or lake bed, as opposed to a controlled environment such as a hatchery.

Natural Mortality
Deaths in a fish stock caused by predation, pollution, senility, etc., but not fishing.

Natural production
See Naturally spawning populations.

Natural Return Ratio (NRR)
An estimate of the ratio of naturally produced spawners in one generation to total natural spawners (both naturally and hatchery produced) in the previous generation.

Natural selection
Differential survival and reproduction among members of a population or species in nature; due to variation in the possession of adaptive genetic traits.

Naturalization
The process by which introduced fish successfully establish a naturally spawning population.

Naturally spawning populations
Populations of fish that have completed their entire life cycle in the natural environment without human intervention.

Net Increase (or decrease)
New body substance elaborated in a stock, less the loss from all forms of mortality.

Net pen
A fish rearing enclosure used in lakes and marine areas.

Nitrogen Supersaturation
A condition of water in which the concentration of dissolved nitrogen exceeds the saturation level of water. Excess nitrogen can harm the circulatory system of fish.

Nominal catch
The sum of the catches that are landed (expressed as live weight or equivalents). Nominal catches do not include unreported discards.

Nongame wildlife
All wild vertebrate and invertebrate animals not subject to sport hunting.

Nonpoint source pollution
Pollution that does not originate from a clear or discrete source.

Northwest power act
The Pacific Northwest Electric Power Planning and Conservation Act of 1980 (16 U.S.C. 839 et seq.), which authorized the creation of the Northwest Power and Conservation Council and directed it to develop this program to protect, mitigate and enhance fish and wildlife, including related spawning grounds and habitat on the Columbia River and its tributaries.

Nutrient cycling
Circulation or exchange of elements such as nitrogen and carbon between nonliving and living portions of the environment.

Nutrient depletion
Detrimental changes on a site in the total amount of nutrients and/or their rates of input, uptake, release, movement, transformation, or export.

Objective
A specific statement of planned results to be achieved by a predetermined date. Once achieved, the objectives represent measurable progress toward attainment of the broader goal.

Obligate species
A plant or animal that occurs only in a narrowly defined habitat such as tree cavity, rock cave, or wet meadow.

Ocean take
The portion of the total harvest for a species or stock that occurs in marine areas.

Ocean type
Ocean-type chinook salmon populations primarily emigrate to the ocean as subyearlings, although yearling emigrants do occur in some populations. Once in the ocean, ocean-type chinook salmon tend to migrate along the coastlines rather than move directly offshore. Morphologically, ocean-type chinook salmon have fewer vertebrae (70>) than stream-type chinook salmon (<70). Genetic differences between ocean- and stream-type populations are similar to those observed between coastal and inland steelhead and odd- and even-year pink salmon.

Ocean-maturing
Steelhead that enter fresh water with well-developed gonads and spawn shortly thereafter; commonly referred to as winter steelhead.

Odd-year pink salmon
Pink salmon that spawn in odd-numbered years. The distribution of these fish is variable, but their abundance tends to increase at lower latitudes in both Asia and North America. Odd-year pink salmon are common in both southern British Columbia and Washington.

Odd-year run
A population of fish that returns to its natural spawning grounds in odd numbered years, such as the pink salmon.

Off-channel area
Any relatively calm portion of a stream outside of the main flow.

Off-site enhancement
The improvement in conditions for fish or wildlife species away from the site of a hydroelectric project that had detrimental effects on fish and/or wildlife, as part or total compensation for those effects. An example of off

Offpeak hours
Period of relatively low demand for electrical energy, as specified by the supplier (such as the middle of the night).

Old-growth associated species
Plant and animal species that exhibit a strong association with old-growth forests.

Old-growth forest
A forest stand usually at least 180-220 years old with moderate to high canopy closure; a multilayered, multispecies canopy dominated by large overstory trees; high incidence of large trees; some with broken tops and other indicators of old and decaying wood (decadence); numerous large snags; and heavy accumulations of wood, including large logs on the ground.

On-site
Usually refers to projects or activities designed to address harm caused to fish and wildlife at the site of the harm.

Operating year
The 12 month period from August 1 through July 31.

Operational plan
An action plan that generally addresses how the objectives in a specific geographic area will be attained.

Opercle
Refers to the largest bone in the operculum.

Operculum
The gill cover.

Optimum Yield
(OY) The yield from a fishery which provides the greatest overall benefit to the nation with particular reference to food production and recreational opportunities; it is based on MSY as modified by economic, social or ecological factors. Precision and Accuracy Precision is the closeness to each other of repeated measurements of the same quantity or object, while accuracy is closeness of a measured or computed value to its true value.

Oregon Production Index (OPI)
An annual index to the measurable number of 3-year-old adult coho salmon south of Illwaco, Washington.

Outfall
The mouth or outlet of a river, stream, lake, drain or sewer.

Outflow
The water that is released from a project during the specified period.

Outmigration
The migration of fish down the river system to the ocean.

Outplanting
Hatchery reared fish released into streams for rearing and maturing away from the hatchery sites.

Overstory
Trees that provide the uppermost layer of foliage in a forest with more that one roughly horizontal layer of foliage.

Oxbow
An abandoned meander in a river or stream, caused by neck cutoff. Used to describe the U-shaped bend in the river or the land within such a bend of a river.

Pacific Salmon Treaty
A treaty signed by the United States and Canada in 1984 that governs the harvest of certain salmon stocks in the commercial fisheries of Alaska, Canada and the western continental United States.

Palatines
Paired bones in the roof of the mouth, lateral to vomer; may bear teeth.

Papilla
A small fleshy projection.

Papillose
Covered with papilla.

Parapatric
Having some geographic overlapping of distributions with the potential for gene flow between populations. See sympatric and allopatric.

Parasitism
The act of living in close association with another living organism at that organisms expense.

Parietals
Pared bones on posterior roof of skull, lateral to supraoccipital.

Parr
The developmental life stage of salmon and trout between alevin and smolt, when the young have developed parr marks and are actively feeding in fresh water.

Parr marks
Distinctive vertical bars on the sides of young salmonids.

Passage
The movement of migratory fish through, around, or over dams, reservoirs and other obstructions in a stream or river.

Pathogens
Any agent that causes disease, such as a virus, protozoan, bacterium or fungus.

Peak flow
Refers to a specific period of time when the discharge of a stream or river is at its highest point.

Peak load
The maximum electrical demand in a stated period of time.

Peat
Partially decomposed plants and other organic material that build up in poorly drained wetland habitats.

Pectoral fins
The anterior(front) paired fins, attached to pectoral (shoulder) girdle.

Pelagic
Of or in the open ocean or open water.

Pelvic fins
Posterior paired fins, located in the abdominal position or towards the rear.

Perennial streams
Streams which flow continuously.

Peritoneum
Membrane lining the body cavity.

Pharyngeal teeth
Teeth located behind the gills and before the esophagus, and anchored in bone.