It is a croaker (family Sciaenidae), and a member of the genus Menticirrhus (commonly called kingcroakers or kingfish). I can't see the sides of the body to see if it has dusky bars or not. If it does, it's probably a Southern Kingcroaker (Menticirrhus littoralis). If not, I think it's most likely a Gulf Kingcroaker (Menticirrhus littoralis). The dusky tip on the dorsal fin suggests it's more likely the latter species. I can see why they would be called "whitening". That's a corruption of "whiting", which is an unrelated fish with a barbel and similar body shape. Sniperhank's scientific name refers to true whiting - and shows how confusing common names can be.
