Maine mammals

Atlantic White-sided Dolphin in Maine

Leucopleurus acutus

Native to Maine SNR Unranked in Maine

Not listed as nonindigenous in Maine by USGS NAS; native to its Maine range.

IUCN Red List status

NE – Not Evaluated

Not yet assessed against IUCN Red List criteria.

Atlantic White-sided Dolphin in Maine, by the numbers

Occasional in Maine 49th most recorded of 85 mammals logged in Maine

38 occurrence records

Records from 2000–2026.

When to look for the Atlantic White-sided Dolphin in Maine

Most sightings fall in August.

38 Maine occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence.

Monthly Maine records (table)
MonthRecords
January0
February1
March4
April2
May1
June0
July5
August21
September3
October0
November1
December0

Monthly atlantic white-sided dolphin occurrence records (iNaturalist and GBIF) in Maine, 2000–2026.

Seasonality

Year-round in Maine, with recorded sightings peaking in August.

Occurrence map

Where Atlantic White-sided Dolphin has been recorded in Maine

38 records mapped · zoom and drag to explore

35 Maine records mapped

Where it's recorded in Maine

CountyRecords
Washington County 4
Cumberland County 3
Hancock County 2
York County 1
Other localities 28

The complete county distribution, spread across 4 Maine counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Maine’s record for this dolphin is modest: 38 reports since 2000, and 28 of them carry no county at all because they were logged from open water. The onshore scatter is what you’d expect along this coast: Washington County leads with 4, and Cumberland, Hancock, and York counties fill in the rest, a thin line of sightings and strandings from the southern beaches to Downeast.

August dominates the calendar with 21 records, and that’s the one month when Maine’s whale-watch boats, research cruises, and summer crowds are all on the water at once, so observer effort explains at least part of the spike. The Gulf of Maine is genuine habitat for the species, a cold-water dolphin that follows herring and other schooling fish, so the low numbers say more about how rarely offshore animals get reported than about how rarely they occur. NatureServe hasn’t ranked the species in Maine. For an animal that lives beyond the breakers, a quiet record is normal, not a warning sign.

Occurrence data from iNaturalist.

Atlantic White-sided Dolphin in other states

More mammals in Maine in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

  • GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
  • iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
  • NatureServe ExplorerCC-BYthe state conservation rank
  • IUCN Red Listattributed factthe global conservation status
  • USGS NASpublic domainnative / introduced status
  • Natural Earthpublic domainthe relief basemap
  • USFSpublic domainnational-forest boundaries