Police seized the marine animals after intercepting and inspecting a number of fishing boats returning to shore to offload.
A woman was detained during proceedings.
According to the Maritime Police, sea cucumbers are considered a delicacy by the Asian community and in Portugal can fetch up to €200 a kilo.
As the cucumbers were still alive they were immediately returned to the sea.
In related news, at the beginning of this week Portugal’s ASAE health and safety authority also announced that it had seized 38 tonnes of frozen fish products from a storage facility in Aveiro.
Officers inspected the unit on 22 January and seized 37 tonnes of frozen sardines and other ground fish products worth around €19,000, due to a lack of compulsory identification labelling.
A further 1,500 kilograms of other frozen food products including pork, poultry and vegetables worth in the region of €750 were also confiscated for being out of date.