There are several locations you can visiting and explore in New Pokémon Snap. One of these locations in the Lental region is the Maricopia, and it’s full of aquatic Pokémon, with a tour of the beach, the reef, and the ocean floor. There are unique Pokémon to each region, but in the Maricopia Reef, there is a large whirlpool that you can activate. There’s a request called Whirlpool Blast Off that you can lure the Pokémon making that whirlpool and snap a picture of it. You want to make sure you visit the Maricopia Reef during the evening.
You want to wait to find the whirlpool around the start of the tour. It’s on the right side of the tour. You want to consistently throw in illumina orbs to the center of the whirlpool. It might not look like they’re doing anything, but continue throwing them at the center.
Eventually, a Blastoise’s shell will float up to the surface and above the water. The Blastoise will face a direction and blast off using its cannons towards the direction of the Wailord. You want to capture as many pictures as you can of Blastoise using its cannons to zoom away. After you’ve captured that image, make sure to show it to Professor Mirror at the end. It should be a four star image.
When you return back to camp, make sure to check the request’s page to complete it, and receive your reward.