Most Atlantic salmon die after spawning. However, a small proportion, mostly females, survive and return downstream as kelts to feed and recover in coastal waters. Some will return to spawn again the next year.
For juvenile salmon in rivers, low water temperatures and reduced food availability mean that growth is slowed until the water starts to warm up again in spring.
Spawning – this month, adult male and female salmon pair up in the headwaters to spawn. The fish undergo marked transformations prior to spawning, becoming coloured and with males often developing distinctive hooked jaws. Males vigorously compete for female partners in the spawning areas.
The female lays the orange eggs in a depression excavated in the river gravels – this is called the redd. She lays about 1100 eggs for every 1 kg she weighs. After fertilisation by the male, the female covers the eggs with gravels to protect them.
This is an ideal month to see adult salmon leaping over waterfalls, weirs and other obstructions as they migrate up rivers to reach their spawning areas.