Local aristocrate of clean waters
Grayling needs oxygen rich and cool water. Yet slight entrophication and acidization will affect on grayling.
Grayling is local fish, except of spawning-time. Every grown fish has it's own territory that it defends aggressively. In flowing waters graylings winter in deeper spots with slower stream and in summer they go for harder flow. In lakes and seashores grayling likes reef-areas and stony strands.
Eating
The most important food for grayling is variety of bottom-fauna. It also eats small fish and also insects from surface. When eating from the surface - usually when weather is calm - fishing graylings with flies is exciting.
Spawning
with whitefish.
Grayling is along with smelt an exception in salmonidae-family as they spawn in spring. Depending on geographical location, it takes place on May-June.
Spawning sites locate on shallow waters with gravel-bottoms. In spring male fish are extra aggressive as they capture their own territories that they defend. Territory borders usually visible barriers e.g. grooves, logs and large rocks.
Records and special methods
In old yet unofficial Finnish fish record there is 6,7 kg grayling. That is tough under strong doubts, because newer official records have only slightly over 2 kg fishes.
In Finland grayling is mainly recreational fisher's catch. Pros get it as a side-haul of whitefish. Grayling tastes good, although some older people of northern Finland look down a bit on it.
Sources:- Koli, Lauri, Suomen kalat
- FGFRI's stats (In Finnish)
- Fish records (In Finnish)