To be made in the likeness of love is to share its nature and nothing else, so that a mind's true identity is not a small self hemmed in by a body but the reflection of its Source. The dominion given is not a rule imposed on beasts and seas, it is authority over the contents of thought, the power to choose which teacher a mind will follow and so what it will see.
The creatures of water, air, and land are the levels of a mind's own experience, its deep impulses, its wandering thoughts, its heavy habits. A mind that remembers whose likeness it bears remembers too that it is the chooser and not the chosen, and that no thought has power over it except the power it agrees to give. What rules your mind is always what you have decided shall rule it.
Fish of the sea: the deep and half-hidden feelings that move beneath awareness, the impulses a mind can learn to guide instead of fear.
Fowl of the air: the fleeting thoughts that dart through the mind, the mental restlessness that seems to have a will of its own.
Cattle and the earth: the settled habits and the whole field of experience, the ground on which a mind acts out what it believes.
Creeping thing: the small clinging fears that stay close to the ground of the mind, the low anxieties that keep it looking down.