Two pairs, doing two different jobs. One warm, waterproof and windproof pair for splashy transfers, cold Zodiac rides and any time you're stationary. Mittens are often warmer than gloves if your hands run cold. Then one lighter fleece, liner or photography glove for dexterity with a phone, binoculars or camera controls. Carry both on every outing.
Two functional pairs is the practical minimum rather than a luxury. Gloves get wet and gloves get dropped over the side of a Zodiac, and a spare pair matters more than a third bulky sweater. Keep the backup in a small waterproof pouch or clipped dry bag.
If you're shooting photographs, test touchscreen material before you travel rather than discovering it doesn't work at minus two. Some photography gloves expose the thumb and shutter finger while covering the rest of the hand, which is a good compromise.