Also The two species belong to different taxonomic genera which means they are not real closely related similar to GSF, BG, RES, pumpkinseed sunfish, and several of the other sunfishes which all belong to the same genus (Lepomis). Past research has found it real difficult to hybridize fish from different genera. DNA or chromosomal composition is probably enough different between Yperch and walleye to prevent successful union of egg and sperm and allow development of an embryo to full term. FYI: genus of Yperch is Perca and for walleye and sauger it is Zander (old name - Stizostedion)

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