Loss of Innocence
The speaker of the poem, though never named and minimally described, is implied to be a young woman. In the beginning of the poem, she is standing on the shore daydreaming that mermaids in the water are looking up at her, and the hulking ships are alive and peering down at her, seeing her as a tiny mouse. This daydreaming is childlike, something that is reaffirmed when she identifies herself with a creature as small and meek as a mouse. She more directly speaks to her youth and inexperience when she states that "no Man moved Me - till the Tide," implying that she has never had romantic or sexual feelings for a man before. But these new feelings, instead of being exciting, are terrifying, and she visualizes the experience through the image of herself, a single dewdrop on a dandelion, being swallowed by a monstrous sea. The experience is initially so shocking and violating that she is frozen, until she finally "starts" and breaks into a run. Over the course of the poem, the speaker's fanciful daydreams turn into living nightmares. Though the poem abruptly cuts off after she escapes, and we do not get to see the speaker process what has just happened, the shift in the poem's mood and imagery from fanciful and carefree to harrowing and grave imply that a serious change has occurred—namely, the loss of the speaker's innocence.
The Mystery of Nature
One of the major themes of the poem is the essential mysteriousness of nature. The speaker oscillates between wonder and fear as she describes its various aspects. She marvels at "mermaids," "frigates" and "hempen hands," but appears terrified by the notion of being swallowed up by it "as wholly as a Dew / Opon a Dandelion's Sleeve." The sum total of these is observations is awe at the ocean's hidden vastness. The speaker offers this mixture of emotion to encapsulate the plurality of her feelings about witnessing such immense unknowability. Hers is an appreciation of the ocean's majesty and power as well as a strong undercurrent of fright at its depth.
Fear
After the second stanza of the poem, the speaker's descriptions become markedly fearful. This is, not coincidentally, when the speaker personifies the water as a man. The threatening quality in this section is intimated by the subtle violence of the words that the speaker employs. She describes how the water touched each article of her clothing, moving up from her shoe, to her apron, and then to her belt and bodice. The fear described is one of specific, unwanted physical contact, but it is also a more general distrust of men. In the fear of the water itself there is an intimation that men, in relationships, swallow women's lives. This idea of entrapment is even captured in the way that water creeps up on the speaker slowly, before all of a sudden she registers the threat it poses.
