Ocean temperatures along and near the New Jersey coast have averaged between five and 10 degrees above normal since late last year, a phenomenon that has intrigued some scientists and has excited area residents and fishermen.
The mild winter meant that water retained much more heat than usual. When the weather warmed quickly this spring, it took significantly less time for the ocean’s temperature to rise.
Additionally, the tranquil winter brought few storms to churn up the water; combined with significantly fewer days this summer of strong westerly winds that create upwelling, the water warmed quickly and has stayed warm, said Josh Kohut, an oceanographer with Rutgers University.
Winter’s lowest recorded ocean surface water temperature was about 40 degrees, according to the National Oceanic and Atmospheric Administration. The surface water temperature reached the mid-70s in June and the low 80s by July. A typical water temperature in June is in the mid-60s and in the mid-70s by July.
The surface isn’t the only part of the ocean that is warmer; temperatures at the bottom of the sea also are above average in places. The boundary between colder bottom water and warmer surface water, known as a thermocline, near the New Jersey coast has seemingly blurred and weakened, according to data collected by a autonomous glider that has “flown” underwater for several weeks this summer.
“We’re noticing that the thermoclines are much deeper and much weaker, said Bob Schuster, a state Department of Envirnomental Protection section chief who works with the glider program. “(The warmth) is much more uniform throughout the water column.”
The glider, which is about to be redeployed for another three-week mission, is a part of a joint program with the DEP, Rutgers and the U.S. Environmental Protection Agency to study the amount of oxygen in offshore water. However, the glider, which is a $108,000 torpedo-like device, also measures many other physical characteristics, including temperature profiles.
Eel grass and shark tales
The warm winter also meant that the back bay waters never got very cold and warmed up quickly once the early spring arrived. Flounder have fled the bay shallows for deeper holes near inlets or have gone out into the ocean seeking cooler temperatures. Crabs began crawling out of the mud in the middle of March, weeks ahead of normal.
Bay temperatures have been in the upper 70s to low 80s in most places since early June, but in the grass flats of Barnegat Bay, the water temperature has been just below the threshold that causes heat-sensitive eel grass to die off, said Richard Stockton College professor and sea grass researcher Jessie Jarvis.
Sampling trips so far this summer in Barnegat Bay have shown a typical seasonal decline of the grasses, but “it’s too early to tell if water temperatures are resulting in a greater than normal decline,” Jarvis said.
Warmer water also affects which species hang around offshore. Fish tales, whether about sharks or large game fish swimming much closer to shore than usual, abound among fishermen this summer.
Reports of large toothy sharks can be heard in bait shops, from fishing enthusiasts and even at shore bars, but Richard Stockton College Marine Field Station manager Steve Evert said it’s difficult to believe many of the stories of rarer shark species, such as bull sharks, in the area; none of the sightings has been confirmed.
Evert and other marine science researchers have conducted weekly studies for the past three summers near the Little Egg Harbor reef, about eight miles east of the inlet, with a remote-operated vehicle. He said the bottom temperature in 65 feet to 130 feet of water has typically been between 49 and 52 degrees, an environment where the water temperature is relatively stable year-round. This summer, however, the temperature range has been between 55 and 57 degrees.
‘Like Florida water’
Mike Rementer, who is the boat manager at Atlantic Cape Fisheries in Lower Township, tells one of those shark tales. He went out to the artificial reef about 10 miles off the coast of Cape May in early July, searching for the flounder that have fled the warmer bay waters.
“I had a big shark come up to the outboards of the boat. I couldn’t tell what it was, but he came up to the outboards of the boat, he circled the boat and he went back down again. I’m gonna say he was 10- to 12-foot,” Rementer said.
Other fish, such as mahi-mahi, trigger fish and wahoo, arrived several weeks ahead of schedule, in early July. They are in larger numbers and are hanging out closer to shore, and they include game fish that come up from the Gulf Stream, Rementer said. “It’s very rare you see the trigger fish and mahi mahi they’re catching at the (Cape May) reef. It’s crazy.”
Recreational fisherman Joe McDevitt and his sons Dan and Joe Jr. head out on their boat about every week. Asked last week about the conditions, Dan McDevitt immediately said the water was “hot.” They’ve seen many more dolphins and pilot whales when heading up to 60 miles off the coast. The sea turtles in the water are larger and they have seen some of the largest schools of baitfish in their 10 years of fishing area waters.
“It’s like Florida water,” Joe McDevitt said.
Last month, Dan McDevitt said he saw a school of squid at the surface near Cold Spring Inlet — so many squid that he and his sons were trying to catch them and use them for bait.
“We were right out at the inlet. Usually you have to go out 20 to 30 miles before you see them,” he said as he unpacked his boat at Utsch’s Marina in Cape May Harbor from a night of tuna fishing. “They’re usually out in the blue water in the warmer temperatures.”
Despite the heat, there are two missing negative side effects: jellyfish and algal blooms.
Few, if any, stinging jellyfish have been reported along the ocean; however, large groups of nettles have been reported in Ocean County and Monmouth County bays. And the DEP’s weekly aerial survey measuring the amount of chlorophyll A in the water, which indicates the amount of algae, has consistently stayed in the good range, Schuster said.
Typically every spring an algal bloom begins to form in New York Harbor and moves south from Sandy Hook. Last year, in fact, had a record bloom that was highly visible along the entire New Jersey and Long Island coast from satellite photographs.
This year? Nothing.
“Even though the water temperature is up, we haven’t seen any algal blooms,” Schuster said. “It’s the first time in 15 years. It’s really unusual.”
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