We develop a theoretical trade model based on classical welfare economics and apply it empirically to both importers and exporters of shrimp, the most traded seafood, to determine the effects of the Covid-19 pandemic on the excess supply and excess demand of shrimp industry. We consider two time periods and compare these to the base period before the pandemic. Period 1 (March–June 2020): there is a net economic loss globally of $194 million due to lockdowns. Period 2 (July 2020–June 2021): there is a net welfare gain globally of $885 million due to increased shrimp demand. Overall, the global net economic gain was $692 million. For the United States alone, shrimp consumers gained $470 million while shrimp producers gained $24 million, which is relatively consistent with the net quasi-consumer gain of $475 million due to the Covid-19 pandemic.