I can’t find any sources to back up that claim, do you? The highest estimate I found was from Wikipedia
A metastudy in 2005 found that the average catch and release mortality rate was 18%, but varied greatly by species.[17] During an Oklahoma Department of Wildlife Conservation study, up to 43 percent of fish released after being caught died within six days as a result of inadequate holding and weigh in procedures during tournaments.[18] More recent studies reported in Montana estimate that approximately 20% of released trout die from injuries or stress and for those that do not die, their injuries may significantly reduce their ability to feed and grow.[19]