Looking at gill rakers is hard enough with all the info in front of you (something to compare with at a minimum is needed). That is true even with pure species. Yes pure species vary based on local conditioning. The major morphological traits don�t vary as much but yes some. If you are looking at mix species - good luck. For instance does anyone know if the GSF trait for 9-12 short and thick primary gill rakers on the 1st arch or the BG trait of 13-16 moderately long primary gill rakers on the 1st arch is genetically transferred to HBG ( GSF x BG). Answer is the hybrid of GSF X BG has an intermediate appearance of gill rakers .What if it�s a 3 way cross ( HBG X RES). Now to even make it more difficult if a hybrid like TJ�s has 9-12 short and thick primary gill rakers on the 1st arch is it from a GSF or a PS each of which have that trait. Experience and something (its relatives) to compare with can only help in the guess work.