What group of islands and shoals serve as the main vessel routes between the St. Lawrence River and Toronto?

The group of islands and shoals that serve as the main vessel routes between the St. Lawrence River and Toronto is indeed represented by Duck Island and Galloo Shoal. This area is situated in a strategic location along the waterways connecting Canada and the United States, making it essential for navigation.

Navigating through these islands and shoals provides vessels with a clear and safer path across potentially treacherous waters, which is crucial for both commercial and recreational boating. The significance of this route is heightened by the proximity to shipping channels that facilitate the movement of goods, thus underpinning the importance of Duck Island and Galloo Shoal as navigational guides.

In contrast, the other groups mentioned—Long Island and Fire Island, Manhattan Island and Montauk Point, and Block Island and Martha's Vineyard—are situated in different regions and do not serve the same navigational purpose between the St. Lawrence River and Toronto. Their geographical locations and purposes differ significantly from the critical role played by Duck Island and Galloo Shoal in vessel routing.