VILLAS, N.J. - The removal of thousands of dead fish from eight miles of Delaware Bay shoreline is expected to begin Friday after a determination that low oxygen levels in the water likely caused the massive kill.
Water samples taken Thursday "strongly suggest" that extraordinarily low levels of dissolved oxygen - the result of higher air and water temperatures - killed the menhaden, according to state Department of Environmental Protection officials.
The lowest oxygen reading was recorded at Pierces Point, one of the areas hardest hit by the fish kill. Bay water at the time the fish washed ashore was around 85 degrees, approximately 10 degrees above normal for this time of the year.
The kill was spotted around 6:30 a.m. Wednesday, when a 20-foot-wide floating patch of menhaden, also known as peanut bunker, was seen along the bayfront. Tides brought the dead fish onto the bay shore from Kimbles Beach in Middle Township to Villas in Lower Township. No other species appeared to be affected.
Though water samples were taken a day after the kill, conditions had not changed substantially, according to Robert Van Fossen, the DEP's assistant director of emergency management.
The warmer water is, the less dissolved oxygen it can hold, Van Fossen said. At night, oxygen levels also may drop significantly because aquatic plants near the water's edge stop their process of photosynthesis.
"If the fish schooled very tightly in shallows . . . they may have simply used up all the oxygen that was available to them," he said.
An early theory of investigators was that predators had driven the menhaden toward shore and in nearby creeks, where they quickly depleted the dissolved oxygen.
Menhaden, which measure from 31/2 inches to 4 inches, are bony fish not usually consumed by humans. They are prey for species such as bluefish, drum, flounder, mackerel, striped bass, and tuna.
High tide had taken care of removing some of the pungent fish by Thursday afternoon. But the DEP gave municipalities permission to drive front-end loaders and other equipment onto beaches Friday to remove those that remained. The fish will be disposed of in a Cape May County landfill in Woodbine, said Lawrence Hajna, a DEP spokesman.
"All we are asking is that [towns] try to restore the sand on the beaches to as close to natural as possible when they are done," said Wolf Skacel, the DEP's assistant commissioner for compliance and enforcement.
Officials said a fish kill occurred along the bay in the 1970s about the same time of year during a similar weather pattern. Last month in Cape May Point, a fish kill in the freshwater Lily Lake was determined to have been caused by a lack of oxygen due to high water temperatures.
Harry McDermott, 75, a longtime fisherman and Villas resident, said he noticed little fish "jumping out of the water" while he surf-fished on the bayfront Tuesday.
"I knew something wasn't quite right," McDermott said Thursday. "It was weird to see hundreds of them just jumping out of the water as the tide was rolling in. I couldn't figure out what was going on."