The Cu De River, winding through the northwest of Da Nang, flows from the highlands of Hoa Bac commune (Hoa Vang district) to the estuary at Nam O Beach. Its name traces back to the historic Cu De village it nurtures along its lower banks. Here, where river meets sea, an extraordinary natural phenomenon unfolds between February and April of the lunar calendar.

Locals call the mysterious creature "bun me"  -  a curious aquatic being with a rough surface, a soft body speckled in green, and delicate orange-yellow legs. When threatened, it releases a dark purple ink, much like a tiny underwater marvel.

But it is the eggs, called bun song, that have earned a special place in the hearts of Nam O’s people. Resembling fine rice noodles but softer, thinner, and tinged in pale green or gold, bun song appears in tight curls  -  nature’s handmade delicacy.

Harvesting a river's secret

At the river's mouth, especially between February and April in the lunar calendar, a mysterious aquatic creature appears. Locals affectionately call it "bun me," while its eggs are known as "bun song," a treasured gift from nature often transformed into an enticing dish.

"Bun me" has a rough appearance, a soft body, a back covered in greenish spots, and numerous yellow-orange legs. When threatened, it secretes a dark purple fluid.

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"Bun me" has a rough surface, a soft body, and colorful legs. Photo: Bep Ben Suon Doi

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Freshly harvested bun song is considered a rare gift from the river. Photo: Dong Dan Bien

A refreshing bun song salad with shrimp and vegetables. Photo: Nuoc Mam Nam O

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Bun song strands offer a naturally sweet, crisp, jelly-like texture. Photo: Cai Nguyen

According to Mr. Le Uc, a resident of Van Hamlet in Hoa Hiep Bac ward, the Cu De River is rich with aquatic life like jellyfish, fish, snails, and particularly bun song. He describes bun song as slender strands smaller than rice noodles, with a light green or pale yellow hue, curling naturally into small clusters.

"Bun me" typically spawns en masse at night, producing long strings of eggs known as bun song. Locals often set nets along the riverbank at dusk to trap "bun me" during spawning or dive to depths of five meters to hand-collect fresh bun song  -  preserving their quality and fetching better prices at market.

Each diving session usually yields 1-2 kilograms of bun song. After collecting the eggs, the mother creatures are carefully returned to the river. Bun song thrives only in pure, flowing waters; heavy rains or pollution during spawning season can wipe out the harvest entirely.

Freshly spawned bun song is pale green, crisp, and sweet. As it ages and turns yellow, it loses its delicate flavor and prized texture.

Although still relatively unknown to tourists, bun song is a beloved ingredient for local households near the Nam O estuary. Many restaurants now feature bun song dishes, especially bun song salad  -  the most popular way to enjoy this seasonal gift.

To prepare the salad, fresh bun song is meticulously washed to remove any debris, briefly blanched in salted boiling water, then drained. It is tossed with garlic-chili fish sauce and a variety of ingredients like shrimp, pork belly, pineapple, cucumber, shredded carrots, herbs, and roasted peanuts.

"The key to a delicious bun song salad is to mix only after the ingredients have cooled. Mixing while hot ruins the bun song’s natural green color and crispness," said Ms. Kieu Giang, owner of a local eatery in Lien Chieu district.

Ms. Giang described bun song’s flavor as completely unique compared to familiar seaweed types. It has a mild sweetness, a refreshing taste, and a jelly-like crunch that’s perfect for hot summer days  -  a cooling treat loved by children and adults alike.

Thao Trinh