Glossary

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Natal
Birth place.

Natal stream
Stream of birth.

Native population
See Native stock.

Native species
A species of fish indigenous to a particular region.

Native stock
An indigenous stock of fish that has not been substantially impacted by genetic interactions with non-native stocks or by other factors, and is still present in all or part of its original range. In limited cases, a native population may also exist outside of its original range (e.g. in a captive broodstock program).

Natural fish
A fish that has spent essentially all of its life-cycle in the wild and whose parents spawned in the wild. Synonymous with wild fish and with natural origin recruit (NOR).

Natural mortality
Mortality due to natural causes. Mathematical symbol: M.

Natural origin recruit
See Natural fish.

Natural population
See Native stock.

Natural return rate
The number of native, naturally produced fish spawning in on generation divided by the total number of naturally spawning fish (hatchery plus naturally -produced fish) in the previous generation.

Natural spawners
See Natural fish.

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.

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

Non-native stock (population)
A stock (population) that has become established outside of its original range.

Non-target population
Any natural populations that is not intended to be integrated with a particular artificial propagation program.