Barbour, S.E.

English

A study was made of three populations of Arctic charr, Salvelinus
alpinus (L. ). from different habitats.. Differences were found In
morphology. feeding habits. growth, energetics and reproductive
tactics. A pelagic. planktivorous. rather than benthic. life history was
adopted by populations in competition with other salmonids.
Measurements showed morphological coincidence with these life styles.
Growth rate in body length was similar among the populations but
growth in weight was related to the productivity of the habitat.
Final body size was determined by the onset of sexual maturity.
Large, deep, lowland fjord-like lochs produced bigger, heavier charr
than a smaller. less temperate hill loch and a meso-eutrophic Hebridean
loch. Body resources (lean. lipid, energy). expressed as values for fish
of a standard size, were greater in the lowland loch population.
These charr invested more resources in somatic sexual dimorphism while
the hill charr invested more in gonad tissue. The age at maturity and
fecundity were greater in the lowland charr but egg size was smaller.
The size of offspring at the onset of feeding was directly related to
egg size.

It Is hypothesized that the requirement for yolk to ensure alevin
survival may initiate adaptation of the life history. The lowland charr
(hypermorphic. large, old, fecund with small but variable egg size)
resemble the root stock of post-glacial colonization. Large egg size,
early maturity (with its demographic advantages) and 'small body size
with reduced fecundity represent a chain of responses to more
stringent environments

Barbour, Stephen Elliott

Edinburgh Research Archive

Variation in life history, ecology and resource utilization by Arctic charr Salvelinus alpinus (L.) in Scotland

https://era.ed.ac.uk/bitstream/1842/6996/1/350765.pdf

Variation in life history, ecology and resource utilization by Arctic charr Salvelinus alpinus (L.) in Scotland.

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