Times Staff Writer ST. PETE BEACH — Despite last week’s prediction that the lingering Red Tide might move north, the toxic algae bloom still hasn’t begun wreaking havoc here the way it has south of Tampa Bay.On Friday afternoon, the beach behind the Tradewinds Island Resort appeared to be clear of dead fish and full of live tourists."We know that it’s here," but in very low concentrations, said Tampa Bay Watch president Peter Clark.The latest report from the Florida Fish and Wildlife Conservation Commission issued Friday said water samples from 25 locations around Pinellas and Hillsborough counties detected only low or background concentrations of the algae in eight places and nothing anywhere else. Those spots where it was detected include Clearwater Pass, Mullet Key and the Williams Fishing Pier in Boca Ciega Bay."Concentrations were below 100,000 cells per liter in all samples examined," the state report noted. A bloom needs to have a far higher concentration for its toxins to become a problem for marine life.TAMPA BAY TIMES COVERAGE: THE MENACE OF RED TIDEWhy is Red Tide so bad this year? Could dust from the Sahara be to blame?Red Tide’s toxic toll — your questions answeredRecalling the devastating Red Tide of 2005 and dreading a repeatLingering Red Tide bloom moves north, killing fish near mouth of Tampa BayRed Tide is killing turtles in Southwest Florida. Is Tampa Bay next?While there were three reports of fish kills in Pinellas this week, they were not the kind that drives tourists away from the beach.One involved only two fish and may not have been caused by Red Tide; a second one did not include a number for the fish; and the third occurred 25 miles out in the Gulf of Mexico off Pass-A-Grille Beach, said Kelly Richmond of the Florida Fish and Wildlife Research Institute in St. Petersburg.The state also received one complaint about respiratory problems from someone on Pass-A-Grille. There were no further details available about that lone report. The latest prediction from the University of South Florida’s College of Marine Sciences says the surface waters may push the bloom northward, but the subsurface waters seem to be headed to the southeast.No one knows what causes a Red Tide bloom to start. Small, scattered colonies of the microscopic algae known as Karenia brevis live in the Gulf of Mexico all year long. Usually their numbers are so tiny that no one notices. But every now and then, usually in the late summer or fall, the algae population 10 to 40 miles offshore explodes into something called a bloom. The algae multiply rapidly and spread across the water’s surface, staining it a rusty color that gives the phenomenon its name. Then winds and currents carry it toward shore.This year’s Red Tide covers about 130 miles of the state’s gulf coast from Manatee to Monroe counties, and has killed thousands of fish, as well as hundreds of sea turtles, scores of manatees and a dozen dolphins. It has also chased tourists away from beach hotels, pushed beach weddings indoors, scuttled fishing guides’ business and scared off potential waterfront real estate sales.This bloom began in November, which makes it the longest lasting Red Tide this decade. The longest on record lasted for 17 months between 2004 and 2006.Contact Craig Pittman at [email protected] Follow @craigtimes.