Neptunea arthritica is a large marine gastropod mollusk in the family Buccinidae, commonly known the Japanese Neptune Whelk. The genus name Neptunea derives from Neptune, the Roman god of the sea while the species epithet arthritica comes from Greek arthron, meaning “joint,” likely referring to morphological features of the shell or soft body observed by early taxonomists. It is native to the cold temperate and subarctic waters of the North Pacific Ocean, including the coasts of Japan (particularly Hokkaido), the Russian Far East, the Bering Sea, Alaska, and parts of western Canada. In Japanese, it is known as Hime Ezobora (Princess Hokkaido Conch) and the Aotsubu (Blue Whelk). This species inhabits sandy and muddy seabeds in relatively shallow to moderately deep coastal waters.

Historically, it has been harvested by Indigenous North Pacific coastal communities for subsistence, and in Japan and parts of Russia it has long been consumed as a local seafood. In modern contexts, it is commercially harvested in northern Japan and Russia, where it is sold fresh, boiled, or processed.

As a food source, Neptunea arthritica is valued for its firm, slightly sweet flesh. The edible portion is primarily the muscular foot, which is typically removed from the shell and cleaned before cooking. Traditional preparation methods include boiling, steaming, slicing for sashimi, and incorporating into soups and stews. In Japanese cuisine, especially in Hokkaido, whelk meat is often served as sashimi, lightly boiled and sliced, or simmered in seasoned broths. In some northern coastal communities of Alaska and the Russian Far East, whelks have been boiled or dried for preservation.

Significant bioactive compounds present in Neptunea arthritica include high-quality marine proteins; omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), associated with cardiovascular and anti-inflammatory benefits; taurine, vitamin B12 (cobalamin), and trace minerals such as zinc and selenium. Neptunea arthritica produces toxic amounts of the neurotoxin (tetramethylammonium ion) in its salivary glands which must be removed before preparation, as boiling does not destroy the water-soluble neurotoxin and actually spreads it instead.