Page 176 - The Miracle of Migration in Animals

The migratory patterns of Atlantic salmon take place over a very broad
area in the Northern Atlantic.

riverbed where they were hatched years before and lay their eggs.
Shortly after fulfilling their duty, the salmon die.
It is hardly likely that without help, a person could manage to
get to his birthplace thousands of kilometers away, by an arduous
route he had only followed once before, without taking a wrong turn.
But from birth, salmon can succeed at something that’s impossible for
humans. It is obvious that salmon cannot develop this ability by their

own efforts and that coincidence cannot provide this species with
such superior talents.
To understand the true wonder of the salmon’s journey, con-
sider what a salmon must take into account as it approaches a river:
First, it has to determine its route. A fish is hatched in some
branch of a river quite a way inland. Rivers often have many
branches. Accordingly, for the salmon to return to where it came, it
must choose the right fork every time. Salmon manage to find their
way on routes they have descended only once before, correctly choos-
ing—again and again—the branch of the river that will take them to
their natal streams.

174