Ebb & flood / Tidal range
Every 6 1/4 hours the tide comes and rinses fresh, cold sea water to the coasts.
The rising water brings abundant small forage fish and large swarms of 60-70 cm big saithe or 30-40 cm long mackerel from the North Atlantic to the coastal regions, because they are also hunters.
The purposeful fishing technique from the boat is to find such a swarm of e.g. saithe or mackerel in front of the rising water, the peak of the flood.