Trout Spawning, River Ayr.

These trout spawning in the Stottencleugh Burn at the head of the Ayr catchment are destined to fail. The anoxic conditions in the gravel kill the eggs as we've proven with egg box trials. It's a shame but still great to see the first spawning of the year.
Iron rich water due to historic mining activities is the cause of the iron rich water. You can see the gravel in this burn is orange (due to iron) and where the trout are digging redds the underlying substrate is black. There is a very poor oxygen transfer to the gravels beneath the orange crust hence the substrates are black and anoxic. Eggs require oxygen to survive and here unfortunately they don't get any.