Note that weight of an object depends on the gravity and its mass. Its formula is:
where W is the weight, m is the mass and g is the gravity. The value of gravity in earth is 9.8 m/s^2.
So to determine the weight of the fish, substitute m=69.0 kg and g=9.8 m/s^2 to the formula.
`W = 69 * 9.8 = 676.2`
Hence, the weight of the fish, rounded to the nearest whole number, is 676 N.