The marine environment clearly requires a pair of binoculars with special features. For starters, they have to be fully weatherproof – both water- and fogproof. Furthermore the fact that the base from which they are used are unstable (a moving boat), magnification has to be fairly low: Ideally 7x. (Unless you use an image stabilizing binocular).
One of the drawbacks of higher magnification is the fact that movement is amplified, so using a binocular with high magnification from a moving boat will be very difficult.
Ideally the aperture should be quite big, since the more light is gathered, the clearer the image (which is important, since foggy or hazy condition will make getting a clear image difficult). Experience showed that 50 mm. is the ideal lens diameter for a marine environment. Another important point often overlooked is the fact that a viewer (in a marine environment) usually focuses on distant objects, so a pre-fixed focus or “auto-focus” binocular is actually a good choice. Finally, a good marine binocular has to have a wide angular field of vision.
These matters are discussed in “How to choose marine binoculars”, as well as the best marine binoculars from different price ranges.