1 Stock A group of individuals of the same species where immigration and emigration are negligible in relation to growth and mortality A stock is a selfcontained population with its own spawning area ID: 510555
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Slide1
Stock Concept
1
Stock
A
group of individuals of the same
species where
immigration and
emigration are
negligible in relation to
growth
and mortality. A
stock
is
a
self-contained population with its own spawning area.
Fishing
upon one
stock
has no effect upon
other
stocks.”
–
paraphrased from
Holden and
Raitt
,
1974
Subpopulations
of a species for which intrinsic factors (growth, recruitment, mortality) are
significant
factors determining the stock's
dynamics
, while extrinsic factors (immigration and emigration) are traditionally ignored.”
–
paraphrased from
WikipediaSlide2
Conceptual Model of a StockStock Concept2PopulationNumbers
Recruitment
Immigration
Natural Mortality
Fishing Mortality
Emigration
Population
Biomass
GrowthSlide3
Environments of a StockStock Concept3Socio-Cultural Environment
Physical EnvironmentBiotic Environment
Population
Biomass
Recruitment
Growth
Immigration
Natural Mortality
Fishing Mortality
Emigration
Competition
Predation
Behavior
Habitat
Economics
Politics
Traditions
Behavior
BeliefsSlide4
Stock Concept ExampleStock Concept4Slide5
Stock Concept ExampleStock Concept5Slide6
Critique of Stock ConceptToo narrowly focuses managementmove towards ecosystem-based approach that considers other species, habitat, etc.but some debate about what this means.Stock Concept6