Line a baking dish with paper towels and set aside.
Sift the flour, baking powder, salt, and pepper into a mixing bowl. Add the clam juice, eggs, and milk and beat thoroughly with a wire wisk. Fold in the butter and geoduck.
Fill a large saucepan or wok halfway with vegetable oil and heat to 375 degrees. Very carefully, drop large spoonfuls of batter into the hot oil and 3 to 4 minutes, turning once, or until the fritters are golden brown on both sides. Drain on paper towels, then transfer the fritters to the prepared baking sheet and place in the oven to keep warm.
To serve, divide the fritters among individual plates and serve immediately.
Note: Geoducks can be tricky and messy to clean. Any good fishmonger will be glad to clean the giant clam as you desire.