Humpback whales disappeared from New York Harbor for decades. In 2009, three showed up. Today, more than 500 individual whales have been documented in the New York Bight, and the man who started counting them had no marine biology degree.

In this episode of the Ocean Leaders Podcast, host Andrew Lewin talks with PJ Sieswerda about his father Paul, the founder of Gotham Whale. Paul began as a volunteer at the New England Aquarium in Boston and taught himself everything. He picked up knowledge from mentors like MIT's Doc Edgerton and went on to spend more than 40 years in public aquariums in Boston and New York. Along the way he built cutting-edge exhibits, joined an expedition to Alaska to bring back a walrus, and gave behind-the-scenes tours to kids, teachers and Bobby Orr.

When Paul retired, he didn't slow down. He started out tracking seals from local tour boats and asking the community to send him their sightings. Then the humpbacks returned, thanks to cleaner water and the comeback of menhaden. Paul's sighting records became the New York City humpback whale catalog, and in 2011 he founded Gotham Whale. It is a volunteer-driven, membership-funded organization where citizen scientists, boat partners and head researcher Dr. Danielle Brown turn community sightings into peer-reviewed science and classroom education.

PJ shares what it was like to watch his father's legacy grow, how Gotham Whale is moving forward since Paul's passing in 2023, and why getting out on the water helps him heal. If you lead an ocean project, this story shows what one determined person with deep curiosity and a community behind them can build.

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