Bottlenecks at seaports have driven up the cost of seafood in the U.S. significantly, with shipments stranded and freezers full, just ahead of the Lenten season when seafood consumption reaches its peak.

The Wall Street Journal reports that a surge in shipping, of all kinds, has created backlogs at ports and made it difficult to get seafood through the supply chain. The surge is mainly caused by businesses trying to build up their inventories to pre-pandemic levels to be ready for the post-pandemic recovery.

Since most of the seafood consumed in the U.S. is imported, that has led to tight supplies and higher prices, with Thai unio Group paying 30 cents a pound more for frozen fish. Retail seafood prices went up more than 13% for the four weeks ending Jan. 23 from a year earlier.

The situation also has led to a severe shortage of frozen storage, with some fish importers shuttling loads around freezers. “The entire system is seized up. A lot of us are basically driving product around to find if there is any room at the inn,” a seafood importer told the Journal.

The National Fisheries Institute estimates that at current trends, port-related fees will be 20 times higher than last year.