PORTSMOUTH

Ferry riders this week saw firsthand the unpleasant summer phenomenon known as a "crab jubilee."

At the two ferry landings on the Portsmouth waterfront, blue crabs were fleeing from an oxygen-starved Elizabeth River, clinging to pilings and below docks in search of life-sustaining oxygen.

Floating next to them were the not-so-lucky - dead fish, dozens of them, including adult striped bass, baby flounders, croakers and white perch.

Officials at the Virginia Department of Environmental Quality said Friday they have been flooded with calls in recent days about fish kills and scurrying crabs in local waters.

The events seem to be concentrated in Portsmouth and Norfolk, in the shallow and enclosed reaches of the Elizabeth River and lower James River, said Wick Harlan, a state environmental specialist monitoring the trend.

Harlan said the culprit seems to be an old one - algae blooms, which are dying off and gobbling up oxygen as they sink to the bottom of affected waterways.

The blooms have been occurring for decades in much of the Chesapeake Bay during late summer, the result of nutrient pollution and high water temperatures. During rains, nutrients such as nitrogen and phosphorus wash into waterways from city streets, storm drains, development sites, lawns and gardens, parking lots and farm fields.

In proper amounts, nutrients are good for an ecosystem. But when they overwhelm a water body, as they do now throughout the Bay system, algae grows quickly and can cause "dead zones" lacking in oxygen.

Algae blooms last summer were some of the heaviest and most widespread on record in Hampton Roads, but few fish kills were reported. This year, by contrast, the blooms have not been as extensive but are resulting in more kills and more crab jubilees, Harlan said.

State officials found "extremely low" oxygen levels at the High Street ferry landing in Portsmouth on Thursday, Harlan said, following calls from concerned business owners and downtown residents who live near the port.

Betsy Cartier, who runs the Starboards coffee kiosk next to the landing, said she has never seen conditions so bad in her five years on the water.

It started Thursday morning, she said, when scores of sea gulls were picking at dead fish. By Friday afternoon, the smell was "just horrendous," Cartier said.

"Everybody comes off the ferry and wants to know what's going on," she said.

She said she talked to boaters on Friday coming up the Intracoastal Waterway who told her of seeing thousands of dead fish and even snakes on the Southern Branch of the Elizabeth River.

Knitting Mill Creek in Norfolk, near Old Dominion University and the Colley Avenue business corridor, experienced some of the most intensive fish kills this week related to scant oxygen, officials said.

Investigators documented "very high counts" in the creek of a particular kind of algae causing most of the trouble, a species known as Cochlodinium, Harlan said.

The cells of this species can become so large that they might clog fish gills, exacerbating the effects of poor water quality and little oxygen, experts explained.

Cochlodinium arrived in Virginia in 1992 and has been showing up in late July and August ever since, sometimes with gusto and sometimes hardly at all.

Harlan chuckled when asked how long the conditions will continue this summer.

"It's very unpredictable," he said, "and depends a lot on the weather and winds."

Scott Harper, (757) 446-2340, scott.harper@pilotonline.com