A small event could be created to increase the bite rates of a certain fish seasonally. The event could be applied in 3 ways.
1. A random week could be assigned event (EG: from Monday to Monday of the start of every season)
2. The time of the event could be applied in the time passed inside the game itself. A week in "Russian fishing" time could have certain fish increase bite.
3. There could be an Item monthly sold by gold that would increase the bite rate. (EG: The item would last a week in game time and after used, it would be able to be re-bought after a month)
I am suggesting this event cause it is kinda frustrating to have 2 hours do play a day and spending all of it trying to find spots that are active