Data from the seawater challenge experiment are in saltwater-challenge-data.csv as follows: Column 1: PIT: Passive Integrated Transponder number used for individual ID Column 2: cross: AxA, BxB, Hybrid, AxF1, BxF1, F1 (The latter four crosses are from a separate study not discussed in the corresponding manuscript. They were raised in the same manner as the AxA and BxB crosses discussed in the corresponding manuscript) Column 3: FL: Fork length in mm Column 4: mass: in grams Column 5: score: 1, 2, 3, 4 or NA (see explanation below) Column 6: smolt: 0 or 1 (non-smolt or smolt) Column 7: sex: Male, Female, or NA (i.e. failed to assign) Column 8: fate: 0 or 1: (i.e. dead or alive at the end of the experiment) Column 9: Date: date individual was declared dead Column 10: Time: time individual was declared dead