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Recovery Strategy for the Sea Otter (Enhydra lutris) in Canada

5. Glossary of Terms

Acute effect
An adverse effect resulting from a single exposure to a substance.

one member of a pair of genes that occupy a locus (a specific location on a chromosome). One member of each pair of alleles is inherited from the mother, the other from the father.

A term that refers to the ocean bottom or seabed. Benthic animals are those that live on or in the seafloor.

Carrying capacity
This is the maximum population size that can be supported by an area or environment. This is a theoretical concept. In reality, carrying capacity changes as conditions change. This is also known as “K”. Also see equilibrium density.

Chronic effect
An adverse effect resulting from long-term exposure to a substance.

Committee on the Status of Endangered Wildlife in Canada.

Critical habitat
The habitat that is necessary for the survival or recovery of a listed wildlife species and that is identified as the species’ critical habitat in the recovery strategy or in an action plan for the species.

Deleterious recessive alleles
An allele is one of a pair of genes for a trait and may be alternate forms of a gene (brown, blond, red and black hair represent different alleles of the same gene). The effect of a single recessive allele is masked by a dominant allele, however when an individual inherits two recessive alleles it is potentially harmful. This often occurs due to inbreeding in small populations. Also see genetic diversity.

A term that refers to the characteristics of a population. Usually processes that affect the size of the population, birth rates, death rates, immigration, and emigration.

A microscopic organism that drifts in the water. Some species cause red tide.

Equilibrium density
The density of a population at carrying capacity. This is the state at which the population size remains almost steady with birth and immigration rate equal to the death and emigration rate.

Extant population
A population in existence.

A wildlife species that no longer exists.

A wildlife species that no longer exists in the wild in Canada, but exists elsewhere in the wild. 

A wildlife species facing imminent extirpation or extinction.

The number of offspring produced by an individual during some period of time.

Genetic diversity
This is a measure of the number of alternate forms (alleles) of genes in a population. Populations that have decreased generally have low genetic diversity. Genetic variability is what ultimately allows individuals to cope with changing environments. Also see deleterious recessive alleles and heterozygosity.

A unique mtDNA sequence. An individual has the same haplotype as its mother, except in rare cases when mutation occurs.

When the paired alleles for a trait (gene) are different as opposed to homozygous (the same). In small or inbred populations homozygosity (one type of reduced genetic diversity) is common.

A condition in which the body core temperature drops to a dangerously low level.

Immune suppression
The ability of the immune system to fight off infection or disease is reduced. Contaminants such as PCBs, lead and mercury may cause immune suppression in many animals.

Animals without backbones; those that are edible are commonly referred to as shellfish.

Metabolic rate
The rate at which an animal uses energy to maintain body temperature and activity. Sea otters, which must consume 25-33% per day of their body weight in food to maintain their elevated body temperature and activity level, have high metabolic rates.

DNA from structures (organelles) in the cell called mitochondria. Unlike nuclear DNA (from the nucleus of cells), individuals inherit mtDNA from their mothers only. For this reason, mtDNA can be used to trace maternal lineages with great accuracy.

Males mate with more than one female.

Precautionary approach
Recognizing that measures to addressthe reduction or loss of the species should not be postponed for lack of full scientific certainty.

An aggregation of resting sea otters.

Increases to a population caused by the addition of young animals to the adult population.

A dwelling-place, such as a den, nest or other similar area or place, that is occupied or habitually occupied by one or more individuals during all or part of their life cycles, including breeding, rearing, staging, wintering, feeding or hibernating.

Soft-bottomed communities
The animals (often invertebrates) and plants that live in and on gravel, mud and sand bottoms. Organisms such as clams, worms and sea pens are members of soft-bottomed communities.

Special Concern
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Patterns or processes resulting from random factors.

A wildlife species likely to become endangered if limiting factors are not reversed.