NBM Dive Site Resource
Henry C. Daryaw
Brockville, Ontario, Canada
Established St. Lawrence River recreational shipwreck dive documented by an operating regional dive charter or specialized wreck source.
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Original NBM Artwork
Aquatic life at this dive site
What divers may encounter
Three reviewed connections are featured here. Sightings vary by season, conditions, and chance, so they are never guaranteed.
Smallmouth Bass
Micropterus dolomieuNOAA reports smallmouth bass as a dominant summer user of warmer nearshore Great Lakes wreck and reef habitat. Sightings remain seasonal and condition-dependent.
Eric Engbretson, U.S. Fish and Wildlife ServiceOpen Aquatic Life Profile →
Rock Bass
Ambloplites rupestrisNOAA reports rock bass as a dominant summer user of warmer nearshore Great Lakes wreck and reef habitat. Look close to protected wreck structure.
Sam Stukel/USFWSOpen Aquatic Life Profile →
Round Goby
Neogobius melanostomusRound goby are bottom-dwelling Great Lakes–St. Lawrence fish associated with rocky hard structure. Look along lower wreckage and nearby bottom.
Peter van der SluijsOpen Aquatic Life Profile →
Site media
Photographs
Three views rotate from the published gallery on each visit.
Contributor media
Dive videos
Three featured video positions are reserved on every profile.Recent field observations
Diver-reported temperatures
Automatically checked observations from dives during the past 14 days. Three reports are visible at a time; scroll for more.A report that passes the automatic checks will appear here with the dive date, diver’s display name, and temperatures at each depth.
Reports are automatically checked for plausible dates, depths, and temperatures. They are observations, not forecasts; confirm conditions before diving.
Seasonal planning reference
Typical monthly conditions
Long-term averages, not a forecast. Actual air and water conditions can change quickly and may vary across the site.Moderate-confidence match — Matched by documented Great Lakes port/area. Air and surface-water values are regional planning averages. No bottom-water line is published because a comparable depth-specific record has not yet been verified.
| Month | Average air | Surface water | Bottom water | Bottom measurement depth |
|---|---|---|---|---|
| Jan | 15.6°F / -9.1°C | 35.9°F / 2.2°C | No reliable record | — |
| Feb | 17.8°F / -7.9°C | 33.5°F / 0.8°C | No reliable record | — |
| Mar | 28.5°F / -1.9°C | 34.6°F / 1.4°C | No reliable record | — |
| Apr | 42.9°F / 6.1°C | 39.3°F / 4.1°C | No reliable record | — |
| May | 55.9°F / 13.3°C | 49.3°F / 9.6°C | No reliable record | — |
| Jun | 64.8°F / 18.2°C | 60.3°F / 15.7°C | No reliable record | — |
| Jul | 69.5°F / 20.8°C | 69.9°F / 21.1°C | No reliable record | — |
| Aug | 67.5°F / 19.7°C | 72.8°F / 22.7°C | No reliable record | — |
| Sep | 59.5°F / 15.3°C | 69.1°F / 20.6°C | No reliable record | — |
| Oct | 47.5°F / 8.6°C | 59.7°F / 15.4°C | No reliable record | — |
| Nov | 35.8°F / 2.1°C | 49.8°F / 9.9°C | No reliable record | — |
| Dec | 23.8°F / -4.6°C | 41.6°F / 5.3°C | No reliable record | — |
NOAA NCEI 1991–2020 U.S. Climate Normals — Massena, NY
1991–2020 climate normalsReview source ↗NOAA NCEI Coastal Water Temperature Guide — Alexandria Bay, NY
Historical monthly station averagesReview source ↗Bottom temperature is never inferred from surface temperature. A blank month means no reliable depth-specific average is available. Data reviewed 2026-08-26.
Why divers know this place
Highlights
Historic St. Lawrence maritime wreck and freshwater habitat.
Before you arrive
Access notes
Inverted wreck in a constricted, generally strong-current section of the river.
Plan within your training
Conditions and hazards
River current, active commercial shipping, cold water, changing visibility, entanglement, zebra mussels, fragile wreckage and possible overhead areas; use a dive flag and appropriate surface support.
Independent resource notice
This record is a starting point for independent verification. Access, closures, moorings, weather, currents, depth, visibility, operator availability, and site conditions can change without notice. Confirm current information with the responsible operator, property owner, managing authority, or another qualified local source before planning or attempting a dive.