It's not just that the water's cleaner - there's more good stuff in it, too. A type of fish called menhaden have come back in numbers that, to hear Sieswerda say it, "local fishermen have not seen in their entire careers." Too oily for human consumption, though whales and other sea life are happy to chow down on them, menhaden are netted for fish oil and fertilizer. But industry regulations passed in 2012 cut menhaden catches by 25 percent, allowing the fish population to grow by an estimated 300 million animals.
"It's a good time for menhaden (except for the ones who are getting consumed)," Sieswerda said. For the whales, it's a good time to hang out near the Big Apple, too.