You might want to look at where they had been harvested from and where they are harvested from now.When did oysters become $4.50 each???
I could really use some of that deflation right now.
Several years ago it was possible to get Apalachicola Bay oysters -- shucked, and I've generally considered that the oysters are almost free; you're paying for the shucking -- for US$0.50 each around the north shore of the Gulf of Mexico. And, contrary to my concerns with oysters so cheap, they were good and did not leave me deathly ill the next day.
Now the Apalachicola Bay is shut down for oyster harvesting through 2025 because reduced flows from the Apalachicola River raised the salinity of the Bay and decimated the oyster crop. Apalachicola oysters once supplied most of the American Southeast.
The last time I had Apalachicola Bay oysters, just before the ban, they were US$15 a dozen and the shucker had to go through about twenty of them to find twelve he was willing to serve. And they weren't very good. Now oysters in the same area come from somewhere in Texas.
And I think there are similar issues with several other traditional oyster sources, maybe even in the British Isles. So, maybe climate change.