REHOBOTH BEACH, Del. - The carcasses of the latest victims of Delaware's summer of fish kills were gone from a canal in one of this resort's toniest neighborhoods late last week, but the stink lingered.
"I saw a pregnant girl had to hold something over her face," says Elsie Dobeck, who was mowing lawns in the Rehoboth Beach Yacht and Country Club. "And a man walking his dog with a handkerchief over his face. Glad I don't live here."
One million dead menhaden floated to the surface a week ago in Torquay Canal, which winds through this community of large colonials, contemporaries and Mediterranean villas off Bald Eagle Creek at the head of Rehoboth Bay. It was the second fish kill of the summer in this canal and one of 10 in the tributaries of Delaware's inland bays, the worst summer since state officials began keeping track 20 years ago.
"The first one was bad, but this is much worse," says Joe Minuti, whose house on Land's End Drive backs to the canal. "This whole bay was covered."
The fish floated for two days outside Minuti's house, pinned in the canal by the wind and lack of a strong tide, until Delaware's Department of Natural Resources and Environmental Control (DNREC) sent a marine harvester into the canal to scoop up the fish and send them to a nearby composting site.
State officials have found Pfiesteria piscicida, blamed for the 1997 fish kill in Maryland's Pocomoke River, in water samples from one of the Rehoboth Bay kills, but can't say whether it was in its toxic state. Rather, they blame a lack of dissolved oxygen in the water for the kills that have fueled public health fears.
The canals that developers dredged to fill marshes to build the houses with boat docks at the back door that are so attractive to upscale buyers have played a major role in this summer of fish kills.
Because the canals, which lace the communities off Rehoboth and Indian River bays, are deeper than the bodies of water they drain to, the water comes in at high tide, but some of it can't get out. Torquay Canal, scene of last week's fish kill, is 18 feet deep, while Rehoboth Bay averages about 4 feet deep.
That lack of flushing action combined with algae growth that sucks dissolved oxygen from the water, a particularly rainy summer that slows the production of oxygen and a bumper crop of menhaden, which don't know enough to go the other way when they hit a bulkhead, is a perfect recipe for large scale fish kills.
"Usually, we average two or three fish kills a year," says Jack Pingree, program manager for shellfish and recreational waters branch of Delaware's natural resources department. "This year, we've had 10."
Surprisingly, there have been no such fish kills in Maryland's coastal bays this summer, despite similar development patterns, leaving scientists struggling for an explanation.
"A definitive answer would take an analysis and comparison of water quality data, and we haven't looked at that," says Robert Summers, director of technical and regulatory services for Maryland's Department of the Environment. "I don't think there's a big difference in population or development patterns, or something like that. It's more likely to be a weather-related anomaly. Or maybe dredging."
The canals that run through Ocean City neighborhoods on Sinepuxent, Assawoman and Isle of Wight bays are barely 4 feet deep, the average depth of those bays. The water flushes with the tides.
"Nature's very random sometimes," says Charles Poukish, MDE's fish kill expert. "There's been years we've had massive fish kills, and they haven't. It may be some things that are unique to the area. But what they are, we don't know."
Delaware officials reported their first fish kill this year July 6 in Bald Eagle Creek and Torquay Canal, the same spot as last week's kill. Then they came almost weekly in Pepper Creek and Love Creek off Indian River, Arnell Creek off Rehoboth Bay and back in Bald Eagle Creek.
"It's almost predictable," says Charles Lesser, natural resource's fisheries administrator. "When you have a continual string of cloudy days, you know you're going to have a fish kill."
The canals were dredged 30 years ago, before anyone worried about permits and wetlands restoration and before the population explosion in the beach resorts of southern Sussex County, he says.
Route 1 from the Maryland line to Rehoboth Beach has gone from a two-lane road to a four-lane highway, usually jammed with traffic during the summer, and chock-a-block with shopping malls and outlet centers. Farther off the road, bulldozers clear trees for the ubiquitous condominium, townhouse and golf course communities with names like The Islands and Sanibel Cove.
The fertilizer runoff from all those carefully manicured lawns and golf courses and the remaining farm fields, polluted ground water, discharges from sewer plants and nitrogen coming from polluted air have turned the canals into stews of nutrient-rich water. The nutrients fuel the growth of algae, which turns the water reddish-brown.
Spurred on by sunlight, the algae produces oxygen through photosynthesis, the same as other plants. But at night, the algae consumes oxygen. On overcast days - there have been about 42 of them in the past three months, according to the National Weather Service - little photosynthesis occurs, producing little oxygen. The algae consumes almost as much oxygen as it produces. In addition, the canals trap organic sediments that use oxygen as they decompose.
Menhaden, tiny fish that swim in large schools, migrate into the estuaries of the East Coast in the spring and summer to feed on the algae and get trapped in the dead-end canals of Delaware's inland bay communities.
"When they hit a bulkhead, they just keep coming," says Lesser. "They just keep piling up in there."
By dawn, dissolved oxygen levels drop below 4 milligrams per liter, the minimum for fish to survive, and the menhaden suffocate.
The solution is a long time coming, and it hinges on controlling pollution sources, says Hassan Mirsajadi, an environmental engineer with natual resources' watershed assessment branch.
"If we can remove pollution from runoff and from treatment plants and the air, things will be improved," Mirsajadi says.
It is possible to redredge the canals to make them "mimic a natural system," says Pingree, but "no one has seriously considered that."
Greer Wakefield, Minuti's neighbor on Land's End Drive, blames the problem on Rehoboth's sewer plant, which discharges into the canal system.
"If they just piped it about a mile, mile and a half off the beach during the summer, when the population goes up, that would take care of it," he says.
As he spoke on a cloudy afternoon last week, schools of menhaden rippled the otherwise flat, reddish-brown surface of the canal, and seagulls circled overhead, occasionally plunging toward the water. The bulkhead loomed ahead.