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Lifecycle of the Salmon
Wild Atlantic salmon vary in appearance during their lifetime.
Until the early 19th century the life cycle was not understood
and documented, and Parr and Smolt were assumed to be different
species of fish.
EGGS - Pea-sized orange eggs are deposited in riverbed
gravel in autumn, and hatch the following early spring. As the
eggs develop, the eyes of the developing wild salmon can be seen
through the semi-transparent membrane.
ALEVIN - The partly transparent alevin hatch and remain
hidden in the riverbed gravels, feeding from the attached yolk
sac. They are about 2 cm or less than 1 inch in length.
FRY - Wriggling up from the gravels, fry begin feeding on
microscopic life in the stream. They eventually reach a length
of 5 to 8 cm./2 to 3in. before transforming into parr.
PARR - The vertical markings, called 'parr marks' appear,
with a single red dot between. Parr remain in the river for 2 to
6 years, depending on water temperatures and food availability.
SMOLT - At a length of 12 to 24 cm/4.7 to 9.5 in. a
springtime transformation of the parr takes place into smolt. A
silvery sheen replaces the parr marks, and internally they
undergo a complex transformation to survive in saltwater. On the
downstream journey the odors of the smolt's native river are
imprinted on its memory, to be recalled when it returns to
spawn.
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