A speaker and a young girl stand together looking out at the sea, hoping to spot the spouts that give away dolphins or whales. The girl's opening question, "Who're you," is a small surprise. It's playful and a little puzzling, and the poem never explains it. The speaker doesn't say who the girl is, so we're left to guess at their relationship.
None of the animals show up, and the speaker admits this with mild disappointment. But the second stanza shifts the focus. This is a birthday: candles to blow out, and eight lights that glint in her smiling face. The "seeds of joy" suggest that the day matters more than any sighting.
The mood is gentle, warm and quietly affectionate. The missing dolphins are a small letdown, yet the girl's smile outshines it. The poem seems to say that the real wonder was beside the speaker all along.