Re the American Samoa tuna cannery, the firms in question aver that:
"Chicken of the Sea (headquarters in El Segundo, California)According to Chicken of the Sea officials, limited tuna supply was key factor in the decision to close the cannery. The American Samoa minimum wage increases were a minor factor, but not as significant as other factors related to tuna supply, labor availability, logistics, and utility costs in contributing to the cannery’s closure.(...)
Tri Marine (headquarters in Bellevue, Washington)Tri Marine explained that the American Samoa minimum wage increases were a minor factor—not as significant as rising price competition and high production costs, such as for utilities—in contributing to Samoa Tuna Processors’ closure. "
https://www.gao.gov/assets/gao-20-467.pdf
In both cases, operations were relocated - some to Thailand and the Solomon Islands (lower wages); some to the US state of Georgia (higher wages, better situated) - i.e. no aggregate increase in unemployment.
..not that you can generalise from some little island with a single industry anyway