No. It’s relative. Larger animals require less energy per volume. They are more efficient. Though their overall requirement of energy is higher compared to a small animal. Their relative consumption of energy is a smaller % of their body mass.

There’s not much to buy it’s proven. Large animals have slow metabolisms. Meaning they can go longer periods without food, they require less energy in the form of heat to keep them alive due to having a smaller surface area to volume ratio. Look at animals that are small, some of them require upwards of 100% of their own body weight per day of food to stay alive. Also you’re assuming food is so scarce that it’s difficult to find. That’s not the case, food is relatively scarce compared to other parts of the ocean, but there’s still plenty of it around to eat. That’s not to say small creatures don’t exist at depth of course they do, but compared to similar species that reside at higher depths, they are often larger for this reason plus others. Edit: metabolism per unit of mass.

Sorry I miss spoke. The way of measuring is metabolic rate per unit of mass. That’s what decreases with size. Obviously not the overall metabolic rate. So BMR per KG is the measurement not just BMR. TLDR: The metabolism isn’t ‘faster’ in larger animals, it’s just greater. But more efficient when you compare it per unit of mass.