Desire means to be, to want, to be.
"It is the time when the blowfish wants to go up" means that it is the right time for blowfish to go on sale. This poem is from "Two Songs on the Evening Scene of the Spring River in Huichong" by Su Shi of the Song Dynasty.
Originally, the peach blossoms outside the bamboo have three or two branches, and the ducks are the first to know the warmth of the water of the Spring River. Piper artemisia is full of reed buds, and it is the time when the river dolphin wants to go up.
Translation: Outside the bamboo forest, two or three branches of peach blossoms are blossoming, and ducks are playing in the water, and they are the first to notice the warmth of the river in early spring. The river bank is already full of Artemisia vulgaris, and the reeds are beginning to bud, while the river dolphins are just about to swim against the current from the sea back to the river.
Appreciation
The piper betel artemisia and short reeds, which are yellow and green, are very charming, presenting a scene of spring and prosperity. This poem is about the scenery of the spring river in early spring, and the poet captures the characteristics of the scenery at the time of seasonal change with meticulous and keen feelings, expressing the poet's joy and salute to the early spring.