A harbor seal pup on its way from the Arctic to summer in warmer climes lost its course and wound up on the beach at Beach 74 Street on Monday, causing a gaggle of onlookers, media representatives and police to spend a few hours on the chilly beach last Monday. Rockaway resident Reginald Whitley, 44, was jogging backwards along the beach when he tripped over the beached seal. "I though it was a pit bull or something," he told a Wave reporter. "I was screaming, get your dog." After two hours or so, marine biologists from the Riverhead Foundation for Marine Research and Preservation came along and took the seal away for treatment. Kim Durham, one of the biologists, said that the seal was about 12 to 16 months old and was suffering from infection, an elevated body temperature and dehydration. The last word from the foundation is that the seal is doing just fine. Joe Bonkowski, local manager for the Parks Department, said that this is the third seal to show up on Rockaway's beaches this year. "Most of those who do wash up are not alive," he says. "Fortunately, this one is."