https://hmspermits.noaa.gov/other/BFTsizeclass.doc
Size Class Categories of Atlantic Bluefin Tuna
CURVED PECTORAL FIN APPROX.
SIZE FORK CURVED ROUND
CLASS LENGTH FORK LENGTH WEIGHT
Young school <27 " <20 " <14 lbs
School 27 - <47 " 20 - <35 " 14 - <66 lbs
Large School 47 - <59 " 35 - <44 " 66 - <135 lbs
Small Medium 59 - <73 " 44 - <54 " 135 - <235 lbs
Large Medium 73 - <81 " 54 - <60 " 235 - <310 lbs
Giant 81 " or > 60 " or > 310 lbs or >