1. Orkney Trout Cycle

2. Egg Spawning Trout lay their eggs in nests in river gravels, known a redds. The female builds the nest, usually between November and January when the water is cold and carrying lots of oxygen, because that is what the eggs need to hatch.

3. Egg Hatching As the eggs that have just been laid develop you start to see the ova develop with them. This is called the eyed ova stage. The eggs hatch more quickly if the water they are in is warm. In Orkney we usually try to keep the water at 5 degrees meaning that the eggs take roughly around 90 days to hatch. The newly hatched trout are called alevins, and they live in the gravel having yolk that is attached to their bodies for about 25 days after hatching to feed on. Once again they grow quicker in warmer water.

4. Fry Once the yolk of the alevins has been eaten, the alevins become fry, emerge from the gravel and feed on tiny insects in the water. A lot of brown trout die in this stage. They are only a few centimetres long and consume a lot of energy. They have to find plenty of food quickly as possible. They usually keep away from other fry and are territorial and need stones and plants to hide in. they also need shallow water (1- 40cm) and isn’t fast flowing.

5. Parr A one year old trout is called a Parr. They are small with marks on their scales and they lose these when they age. They live in the same habitat as fry with stones. They will gradually drop downstream with water flow rather than fighting the stream going up.

6. Adult Trout Adult trout have a territory that gives them a good supply of food and a place to hide from predators, preferring deeper pools. In winter they migrate, perhaps miles up river to spawn. Brown trout can live from 5 to 20 years. The whole Brown trout cycle repeats itself.