Prettyfly, the island has many opportunities throughout the summer for various types of fishing. However, if you do not have a boat you are limited somewhat. Places like Tofino, Port Alberni Winter Harbour on the west coast of the island are all good places to fish with a boat. The east coast of the island has been hit or miss in the past few years (mostly miss) due to the salmon migrating around VI as opposed to through the inside passgae. However, that might change this year as there seems to be more herring around the inside passage than in years past and so places like Campbell River, Comox and Port Hardy might be worth a go. A boat is definately an asset in these places.
The island also has some great summer steelheading and lake fishing should freshwater fishing be your fortait. You can always call an island tackle shop (island outfitters) and they can help you more with specifics or flip through a freshwater/slatwater fishing directory (available at your local shop). These directories offer some additional info plus they include maps that are not to bad. Tight lines, winter steel.