Dozens of dolphins swam out of the polluted wa-ters of Haifa harbor on Tuesday. This was thefirst time that dolphins had visited this crowd-ed Mediterranean port, and researchers were surprisedand delighted by the unexpected event. Between 40 and 50 of the dolphins appeared inthe busy port on Tuesday morning, obviously drawnby the fish-rich waters of Haifa Bay. However, the bay is also full of harmful chemi-cals. Aviad Sheinin, professor of Haifa University'sMaritime Studies Department, said he didn't think thedolphins were harmed by the pollution, but that hehoped they would swim back tO sea soon. "It seemsthat they are quite relaxed. They don't seem to bestressed," he said. Haifa Bay is lined by chemical companies thathave been pouring poisonous waste into the water dec-ades. While pollution levels have dropped in recentyears, the water is still considered a health hazard(隐患). "There are" lots of fish in Haifa port. 'Unfortu-nately we couldn't tell the dolphins that the fish arenot healthy; and I don't know what the result willbe," he told Israel Army Radio. Hundreds of Haifa residents gathered aroundHaifa Bay to see the interesting sight, and researcherssaid this provided a rare chance to film and study therough-toothed dolphins. In addition to the dozens ofdolphins which swam into the port on Tuesday, a sim-ilar number stayed outside the breakwater(防洪堤).Later Tuesday the dolphins left the port but remainednear the entrance and Israel's coast guard was patrol-ling(巡逻)the area to try to make sure the dolphinsdidn't reenter the poisonous waters. Relatively little is known about rough-tootheddolphins, which are usually found in deep and warmtropical waters.