What california law passed in 1943? How did it affect papa and other isseis?in farewell to manzanar

The law that was passed in California in 1943 (the one
that is relevant to this book) said that isseis (the Japanese who were actually born in
Japan and then came to America) could not hold commercial fishing
licenses.

This was hugely important because Papa and many
other isseis had owned fishing boats.  If they could not have a commercial fishing
license, they could obviously not be fishermen any more.  This led to Papa staying in
camp as long as he could since he no longer had anything to do once he got
out.