Harbour porpoises are small, shy, cold-water dolphins that pass Delaware’s coast without much fanfare, and the state’s 12 records reflect that. Every county-attributed report belongs to Sussex County, the only one with ocean and bay frontage, and most of the rest of the record set lacks a county tag at all, which often happens with animals documented offshore or found on the tide line.
The timing runs cool-season: March accounts for the largest share of reports, with a few more in April and May. That fits the animal’s habits, since harbour porpoises favor chilly water and tend to slip south along the mid-Atlantic in the colder months. A beachgoer is far more likely to cross paths with one in late winter than on a July weekend.
Twelve records across a quarter-century is a whisper of data, not a measure of how many porpoises actually work Delaware’s nearshore waters. Sightings from shore, boat reports, and the occasional stranding all land in the same bucket, and none of them add up to a population estimate. Treat the map as a record of encounters, not abundance.
Full species profile
