For whatever we lose(like a you or a me) it's always ourselves we find in the sea
There our speaker goes again with the word squishing side notes.
That note's important though, as these last two lines deliver the big "A-ha" moment of the poem (which is made even more apparent by the sudden capitalization of "For").
The speaker is pretty much saying that we can expect to lose things all the time (even people, even ourselves), but at the end of the day the sea has a way of reminding us of what life is all about. And when we have a moment to explore the simpler aspects of the natural world, we tend to learn something about who we really are.
As far as technique goes, line 11 is made up of something called anapests, which aren't actually pests at all but rather poetic feet that create a certain rhythmic effect. Just like the dactyls we saw earlier, anapests help to create that sing-song-y nursery rhyme sound, which in this case that goes like this: dadaDUM.
Anapests follow the same pattern as dactyls, just in an opposite way, so the speaker is definitely playing with that sound throughout the poem. Check out "Form and Meter" for more details.
The cute little rhymedcouplet ("me" and "sea") also has a way of linking nature with people in a direct sort of way. You'll find your "me" in the "sea" with everything else.
At the end of the poem, the speaker is showing us how we've taken an important trip, right alongside maggie and milly and molly and may. No matter which character you identify with most, chances are you have experienced the emotional impact of each of their scenarios right along with them. You've been soothed, comforted, scared to death, and made reflective about the world and your place in it.
To sum it all up, the sea provides a perfect landscape to see all of these life circumstances manifested in the same mysterious place. And we "find ourselves" there because we suddenly discover that nature reflects, in a much simpler way, that same crazy life stuff we experience every day. And isn't that worth being chased by a bubbly crab?