I'm playing on 7 lakes and, after connecting the lakes with a wide canal and connect the ports to the end points of each canal I can't seem to connect the routes at all?
You must have at least one Ferry Depot to spawn the ferries. It must have a Pathway connected to the Pathway that goes between the various stops/piers. Then connect the route the ferries are to travel between stops/piers. The route cannot stop at the depot, though it can pass by it.
In the image, you have a Pathway connected from the ferry-bus hub in the foreground to a single building in the background. Not sure what it is, but I think it is the depot.
If it is a depot, then the route cannot connect there. If it is not a depot, then there is no depot on your pathway either, so no ferries could spawn at the depot and get onto that route. The third building in the background is not connected on the Pathway.
It's like the buses. Buses don't stop for passengers at the bus depot, they just spawn there. Pathways are like roads on the water. If you made a bus route somewhere, and there are no roads that connect there back to the bus depot, then the buses can't get there. Same with the ferries.