Atlantic Salmon

It’s the largest salmon species. The Atlantic salmon (salmo salar) can grow to 30 inches (76 cm) and about 12 pounds (5.5 kg) after spending two years at sea. In four or more years they can grow much larger. An Atlantic salmon caught in 1960 weighed 109 pounds (49.44 kg).

Juvenile Atlantic salmon live in fresh water in the river where they hatched for up to 4 or more years. Then they go through a process called smoltification which allows them to live in salty sea water. When they smoltify, their skin takes on a silvery reflective quality, and their body shape is altered. Their gills start to produce an enzyme which can remove sodium from their cells. Various mechanisms activate to regulate their body fluids in the new environment.

As smoltification takes place, the salmon begin their migration to the Atlantic. As the salmon enters the next phase of its life in the ocean, its diet transitions from mostly insects to larger foods such as shrimp, eels, and squid. In the ocean, the Atlantic salmon grows at a faster pace. After two to four or more years at sea, something tells the fish to return to the river where it hatched.

When the salmon reaches its native river, it stops eating as it swims upstream. The salmon’s only goal at this point is to return to the place where it began its life to spawn and reproduce its kind. Pacific salmon die after they spawn, but Atlantic salmon can sometimes recondition themselves to return to the sea and then repeat the cycle of returning and spawning. The fact that Atlantic salmon stay in the ocean for various numbers of years means that if drought strikes the river or stream for a year, it will not end the reproduction of that generation of salmon. How can these salmon find the streams of their origin? Salmon detect the exact chemical nature of the stream, perhaps by odor.

As we examine the life an Atlantic salmon, we have to wonder how this amazing process could have happened by chance. Once again we see the Creator’s design at work.
© Roland Earnst

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