Tons of fish... But bluegill in saltwater?

Type: Tidal
Region: Southern
Location: Breton Bay

In Breton Bay there's been redfish, bluefish, carp, bluegill, striped bass, and white perch. It's saltwater so it's weird there was a bluegill.

DNR Response: A variety of fish that most people consider freshwater can tolerate a fair amount of salinity in areas often referred to as "brackish" where there is a mixing of freshwater and bay water. Sunfish such as bluegills and even largemouth bass and chain pickerel can be found in these areas at times.