GOWANUS, NY — A clean water advocate wasn't the only one to brave the waters of the toxic Gowanus Canal over the weekend.

Kayakers paddling through the polluted waterway spotted a seal swimming on Sunday, said Owen Foote, of the Gowanus Dredgers Canoe Club. The seal came up to their boat, checked them out then continued swimming back towards the harbor. "It was quite a surprise," said Foote, who hasn't seen a seal swimming in the waterway since he started kayaking in it 25 years ago. "It's great to see a very healthy animal in the waterway."

Foote said that the rain storm last week, coupled with a lack of sewage overflows, led to a cleaner than usual water quality for the canal over the weekend. Kayakers also spotted a lion's mane jellyfish in the canal on Sunday, he said. The seal's swim was first reported by Pardon Me For Asking.

The Environmental Protection Agency has started a cleanup of the Superfund site and the water quality has gotten better over the past six years, with the number of swimmable days increasing, the Brooklyn Paper reported.

Despite readings showing less sewage contaminations, experts told the Brooklyn Paper that they still don't suggest taking a dip in the waterway.