Harbour porpoises show one of the starkest source imbalances in this New Jersey dataset: 166 GBIF records against just 6 from iNaturalist, meaning what’s documented here comes almost entirely from stranding networks, aerial surveys, and specimen data rather than people spotting porpoises offshore. NatureServe rates the state population S3, vulnerable, for a species that’s genuinely difficult to observe alive given how briefly it surfaces and how far offshore it typically stays.
The monthly breakdown, drawn from the much smaller iNaturalist slice, shows a March peak of 3 sightings, but with GBIF dominating the total record by such a wide margin, that visible-sighting pattern likely says more about when observers happened to be out looking than about the porpoise’s actual seasonal presence off the Jersey Shore.
Full species profile
