For the rest of this holiday weekend, the state Department of Energy and Environmental Protection will have lifeguards on duty at Black Rock, Silver Sands and Hammonasset Beach State Parks. Other designated swim areas, including Squantz Pond State Park will not have guards on duty. After Labor Day, there will be no lifeguards on duty at any of Connecticut's state park swimming areas. DEEP hired 90 lifeguards to staff eight of the most popular swimming areas of the state park system, at a time when jurisdictions across the country have been dealing with a lifeguard shortage. At this time of year, however, many lifeguards leave their positions to return to school.