Bottom-fishing is a major step in the increase of exploitation of marine resources, requiring specialised craft, technology, and practitioners. However, the onset and development of bottom-fishing is almost impossible to observe directly in the archaeological record, and is usually reconstructed by implication. The shells of common whelk (Buccinum undatum) from a kitchen midden at Carisbrooke Castle, Isle of Wight, southern England, showed a pattern of damage characteristic of harvesting by bottom-fishing, rather than the usual baited pots. Some whelks had survived being dredged several times. The very consistent size-shape relationship made it likely the whelks were all from a single habitat, probably in the fast tidal flows typical of the oyster-beds just north of the island. The whelks were harvested along with oysters: the whelks' shells were encrusted in a similar way to the oysters in the same midden, and the whelks even bore sub-adult oysters (spat), despite these being potential prey for whelks. This may be the first time whelks have been shown to have been harvested along with oysters and also seems the first direct evidence for a bottom-fishery for whelks.