Diadromy

a life betwixt worlds
the fluid chameleon
dives and emerges

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Inspiration
Pacific salmon (Oncorhynchus spp.)

Facts
Fish like to move. Up, down, left and right, across short distances and long. Fish typically move for food and fornication.

Diadromous fish move between marine and freshwater environments. Two forms of diadromy are catadromy and anadromy. Eels (Anguilla spp.) are a classic catadromous animal – they move from freshwater to spawn in the ocean. Salmon are a classic example of an anadromous animal – they move from the ocean to spawn in freshwater

For Pacific salmon, adults spend a few years in the open ocean gorging on herring and krill and avoiding orcas. Then something clicks and it’s business time. Fish move by the millions back toward the freshwater rivers and streams they were born in. Upon arrival home, a mate is chosen, eggs and sperm are released and then Romeo and Juliet die.

Many significant changes occur to salmon during this transition from salt to freshwater (e.g., fish stop eating, testes and ovaries balloon in size).

One of the most strikingly obvious changes is that of colour. In the ocean, salmon are sleek, silver bullets with a bespeckled top – an outfit that provides camouflage from aquatic and aerial predators. In freshwater, adult salmon transform into colourful beasts – colour likely plays a role in wooing potential lovers.

Sockeye salmon (O. nerka) dress themselves in festive holiday colours – red trunks and green heads and tails. Coho salmon (O. kisutch) also blush a little red. Chum salmon (O. keta) don purplish-black stripes. Male pink salmon (O. gorbusha) grow giant, grey humps. Chinook salmon (O. tshawytscha) shine in an olive hue.

I, myself, prefer tall, dark and handsome – but I suppose in the salmon world that’s a grizzly bear.

Photo
sockeye salmon, Thomas Kline

More
here and here

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