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Which came first - the fish or the egg?

Having driven as far as I could along the track leading into the forest, I parked my car at the dead end, and continued on foot. After a series of bends and turns, I followed the hum of voices, arriving in a clearing beside the lake. The small wooden hut, The Hatchery, built over an outlet that flows downstream, is where we had agreed to meet. The small group had already gathered and would not wait for me. It was the last weekend in October, and that meant it was time for spawning. Spawning is the act of extracting eggs from female fish and sperm from male fish, in order to give nature a helping hand to increase reproduction in the wild.

The small group were already wading into the icy cold water of the lake and drawing up conical shaped trapping nets. Disappointingly the first net was empty, something that had never been heard of before. Could this be a a sign of dwindling fish stocks? The next however (of which there were five) had caught two large trout and several smaller. The fish were carefully handled as they were sorted according to sex and placed in a large receptacle filled with water from the lake. The heavy boxes were quickly carried to the sorting bench. This process was repeated with all "traps" being hauled up and emptied until we had a reasonable collection of both male and female trout.

A good understanding of trout anatomy is required before attempting to extract eggs. Mature trout, both male and female, have glands (gonads) on each side of and above the digestive organs. The eggs in the female are held loosely in a thin membrane and when ripe can gently be manipulated towards the vent of extraction.

The actual spawning was a two man job. With one person holding the fish stable, tail down, so the ripe eggs can flow easily, the other person stood on the opposite side of the bench, and with gloved hands gently pressed out the eggs with the thumb and forefinger, beginning pressure just forward of the vent, then further back towards the head where gentle pressure is applied to assist the natural flow of the eggs. Pressure is never applied forward of the ventral fins, as even slight pressure over the heart and liver could injure the fish.

Once the eggs were collected in a bowl, the male fish was held and using the same technique a milky white sperm was extracted to blend with the eggs. Immediately afterwards a small amount of lake water was used to blend evenly. Fertilisation happens within a few seconds after the sperm and the egg meet. It is important to then rinse the eggs before placing them in the vented troughs which are housed in the small Hatchery. It is imperative to remove any debris, excrement or other foreign matter which may affect the egg cleanliness and health.

Circulating water runs through the interlinked oblong troughs to maintain a good supply of oxygen to the eggs while also flushing out waste. This is created by a self flowing conduit which has been dug to the side of the hatchery. Housing only five troughs, this is a small operation though none the less vital in ensuring a healthy future population of wild trout in the lake.

The eggs will remain in the insulated, though unheated, Hatchery over winter before the hatchling (fry) are released in to the wild at the beginning of May, once they have discarded their egg sack. The fish culturist will visit the Hatchery at least once a week throughout that time, ensuring they remove any eggs that have been contaminated or have died. If not removed they will affect neighbouring eggs. #trouthatchery #browntrout #flyfishing #wildtrout #thehatchery #spawning


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