C-MAP Featured Hotspot: Hospital Shoals

Boston Harbor Flounder Hotspot

Named after the hospital that was situated on Rainsford Island (back in the days when the island served as a quarantine for arriving international passengers), Hospital Shoal is a popular winter flounder hotspot in Boston Harbor.

Where you find the warmest water temperatures in the early part of the season is where you’ll find flounder on the feed. Muddy, dark bottom in coves and bays close to the shoreline or next to islands that are influenced by the flush of a warm, ebbing tide in early May will harbor more active flounder. Look for early flounder near the shoreline of Rainsford Island (1).

As the season progresses into June, flounder will spread out and some of the biggest fish of the year will be taken. Bottom composition is very important, so check your charts for the symbol M (2), which designates muddy substrate. Although flounder are known to feed on muddy bottoms, often the largest fish feed along the edges of rocky areas (3) and near depth changes (4).

To fish a wide area like flats that run from Hospital Shoals to Georges Island, drifting is best. Keep an eye on current indicators (5) to plan your drifts. A wind with tide situation is best for drifting, as you can always use a drift sock to slow your drift speed. If the wind is blowing hard against the tide, you’re better off anchoring.

Later in June and into July, shift to areas adjacent to deeper water, such as the Ram Head Flats off of Lovell Island (6). Cooler ocean temperatures in this area will often hold flounder as we head into the dog days of summer.