An ‘egg-celent’ adventure!

To be an Alaskan Coho Salmon is tough! They hatch in the freshwater streams and then swim along an arduous journey to the saltwater. They travel from Northern Alaska, British Columbia, and Washington State to the Pacific Ocean, and Gulf of Alaska and back. (Source: Afspubs Online Library) They must swim back to lay eggs, spawn or mate. An adult lays approximately 4000 eggs in the freshwater streams.

The first month begins with pea-sized, translucent, amber-coloured eggs, with merely their eyes developed. They appear as small black dots. These little jewels are found under the bottom of the river, under the gravel. Weeks progress as the little embryos begin to grow. About two to three weeks later, they begin to spin speedily. By this time, they have developed a short tail.

The tail cuts open the egg shell and they hatch the tail first. Now, the embryos are called ‘alevin’. But, it is supported by a yellow-coloured yolk sac. The casing cracks away slowly disintegrating or being eaten by other mammals. The little alevin now is nourished by the yolk sac, until it learns to swim for its food. It has huge eyes and the yolk sac will fade over a period of time as the salmon baby learns to hunt.

The yolk sac slowly began to shrink as the salmon baby learns to swim and fetch its own feed, smoothening its belly. As the bulky stomach reduces in size, it allows for more movement to take place and for the salmon baby, now called ‘fry’ to swim freely. By this time the fish has now grown up to an inch’s size.

Fast forward a couple of months, the salmon has now matured. Now called a smolt, it’s ready to migrate back into the saltwater. It develops lithe silver bodies with jaws, scales, and fins. As the body readies itself for the swim, it is stronger, longer, and brighter in colour. After another couple of months, a reddish will take over and the ocean journey will commence. The long journey will complete itself if the coho salmon escapes unscathed from predator attacks. Shortly, after spawning the Coho salmon must finally lay to peace.

Their bodies have an incredible mechanism to prepare themselves for the freshwater to sea journey. A salmon’s brain sends special signals to help the fish to react to the changing temperature, daylight, and water levels. Hormones help the salmon to make their blood more compatible with the freshwater environment to cope with the less saltwater content. A similar process takes place when the salt content increases.

However short life, the Coho Salmon teaches us an important lesson in humility and adaptation. Their journey from the ocean to freshwater to back although arduous, is an ‘egg-celent’ adventure!

Source: Discovery Young Discoverer Series

Author: Digital Onca

Digital Onca is a blog that documents the concepts of Digital Marketing and Public Relations. Digital Onca is the effort to stay with the times, understand more deeply, more closely the working of a digital space that is steadfastly emerging around us.

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