If I'm not mistaken, those spotlights are often installed with a through-bolt and a backing plate, or sometimes even a strong adhesive like 3M 5200.
Before you try to pry it off, check inside the cabin or in the anchor locker for any visible fasteners.
If it's adhered, you might need to carefully use a heat gun on a low setting to soften the adhesive.
Take your time and go slowly so you can be cautious and not damage the gelcoat!