The office of Tourism of Douarnenez is a good start for information on local attractions and cultural events in the region:
If you are looking for information about the maritime trades or businesses related to the sea. The Maritime Federation of the bay of Douarnenez is your best bet.
July 24 to 27th 2014 Douarnenez will host its bi-annual maritime festival Temps des Fête:
In 2012 they had a record 1200 boats participate in the festival with over 100,000 people attending more than 60 shows and programs throughought the three ports of Douarenenez & Treboul
The municipality of Douarnenez is also a good resources for local events and attractions of interest as well as practical information about the city.