Delaware’s bottlenose dolphin reports hug the coast. Thirty-five of the 66 records come from Sussex County, where Delaware Bay meets the Atlantic, and Delaware Seashore State Park alone accounts for nine of them. Kent and New Castle counties add a handful of bay records farther north, with the rest scattered along the shore. Counts like these map where people watch from the beach, not how many dolphins swim past.
Reports arrive in every season, but August stands out with 19 records and June shows a smaller rise. That timing fits the mid-Atlantic pattern: bottlenose dolphins work into bays and nearshore water as it warms through summer, then move back down the coast in fall. Winter reports are scarce, which says as much about who is out watching in January as it does about the dolphins.
Not every coastal record is a live sighting; beach-cast animals figure into shore reports too, and Slaughter Beach on the bay side is one of the named spots. NatureServe marks the species not applicable for a state rank in Delaware, since marine mammals range well beyond state lines, and the IUCN lists it as Least Concern globally. The bay refuges at Bombay Hook and Prime Hook bracket the rest of the named record locations.
Full species profile
