A stand-up paddler got close to the dolphin in the Shrewsbury River between Sea Bright and Rumson last week. Marine experts say humans and boats should keep away from the animal.  (Photo by Scott Longfield. Click to enlarge)

By JOHN T. WARD

Without much public notice, a lone bottlenose dolphin has been plying the Shrewsbury River for the past seven months, according to wildlife advocates who are growing concerned about its safety as temperatures drop and its food supply diminishes.

As it has in the past, the National Oceanic and Atmospheric Administration’s fisheries unit regards the dolphin’s presence as a not unusual, and said the animal appears to be healthy.

But Bob Schoelkopf, founder and director of the independent Marine Mammal Stranding Center in Brigantine, expressed frustration that NOAA hasn’t done anything to guide the dolphin northward through the strait that leads into Sandy Hook Bay, and that colder temperatures make such an effort more dangerous for humans.

The dolphin has been in the river since June, according to Scott Longfield, a Fair Haven photographer and volunteer with the stranding center who keeps an eye on the animal, which he said is believed to be an adult male.

The dolphin “has been on his own for that entire time, which is not good for a social animal,” Longfield told redbankgreen. And until recently, food fish has been plentiful and other conditions have been ideal, he said.

But now, after weeks of unseasonably warm conditions, air temperatures fell into the teens early Tuesday morning and were expected to do so again Tuesday night, according to the National Weather Service. Water temperatures were in the high 30s in much of northeastern Monmouth County, it reported.

NOAA spokesperson Jennifer Goebel said Monday that the dolphin is not stranded. “It’s free-swimming and doesn’t have any visible traumatic injuries,” she said.

Moreover, the presence of dolphins in estuaries and rivers is not uncommon, she said, noting that dolphins have been seen in the Navesink or Shrewsbury annually since 2008, when a pod of about a dozen camped out for an extended stay in the Navesink, venturing as far north as Marine Park in Red Bank.

That year, debate raged about what, if anything, should be done to save the last five members of the pod from the impending start of winter. Some animal advocates claimed the dolphins were “trapped” in the Navesink, unwilling to swim beneath the Route 36 bridge between Highlands and Sea Bright then under construction because of noise from the project. The controversy prompted NOAA to hold a conference at Monmouth University to discuss the animals’ plight; about 100 people showed up.

The following spring, a number of dolphin carcasses were found along the banks of the Navesink. It was unknown how many, if any, of the pod’s members made it past the bridge to the bay and open sea.

Schoelkopf expressed frustration Monday that NOAA had been unresponsive to the his nonprofit’s pleas for attention to the situation.

“I’d like the federal government to acknowledge the fact that the animal is there and that it’s not supposed to be” at this time of year, he said. “We cannot do anything without that acknowledgement.”

But even with such acknowledgement, Schoelkopf said, water temperatures make it unsafe for volunteers to try herding the animal through the strait. He said a recent attempt to do so failed.

“We had several boats up there and got behind it to see if it would go forward,” he said. The dolphin “got very close to the bridge, and just turned around.”

NOAA has a hotline, which Goebel said is answered 24 hours a day, that anyone can call to report a marine mammal in distress, but “any information we can get is welcome,” she said. The number is 866-755-6622.