RED BANK, N.J. - Wildlife officials have added some bite to their warnings against bothering a family of bottlenose dolphins hanging out in two New Jersey rivers. They say sharks have been known to frequent the area as well.
Bull sharks, which can grow to between seven and 12 feet long and are among the three most likely species to attack humans, have been known to swim in the section of the Navesink River, where the 15 wayward dolphins have most recently been staying, said Bob Schoelkopf, codirector of the Marine Mammal Stranding Center in Brigantine.
"In that area are bull sharks that go in there quite frequently," he said. "You never know what you might be looking at; it could be a dolphin or it could be a shark."
Wildlife officials have been concerned about a worsening pattern of harassment by boaters and people on personal watercraft getting too close to the dolphins, which have been in the area since June. Federal regulations require that boaters stay at least 50 yards away from the dolphins; harassing them is punishable by a $10,000 fine.
Schoelkopf said it might have been a shark that one man recently tried swimming after seeing something big break the surface of the water. The man's wife later reported the encounter. The animal probably was not a dolphin because it never resurfaced, which dolphins must do regularly to breathe, Schoelkopf said.
He said no one has documented the presence of a bull shark in the river in recent weeks, but "quite a few" injured seals were found in the area showing evidence of having been attacked by sharks.
Teri Frady, a spokeswoman for the National Oceanic and Atmospheric Administration, said there are no plans to try to remove the dolphins from the river or shoo them back out to deep water.
"It all depends on conditions there, if conditions are not good for them there, or if they start to show signs of stress physically," she said.
Neither of those things has yet happened, Frady said.