Spain was also able to physically close off inland waterways for Dutch river traffic after 1625. The Dutch were thus also deprived of their important transit trade with the neutral Prince-Bishopric of Liège (then not a part of the Southern Netherlands) and the German hinterland. Dutch butter and cheese prices collapsed as a result of this blockade (and rose steeply in the affected import areas), as did wine and herring prices (the Dutch monopolised the French wine trade at the time). The steep price rises in the Spanish Netherlands were sometimes accompanied by food shortages, however, leading to an eventual relaxation of this embargo. It was eventually abandoned, because it deprived the Brussels authorities from important revenues from custom duties.