Who writes this crap? A 3456 lb. great white would be a lot longer than 16ft. Notice they somehow have the exact weight “3456”; are you sure it wasn’t “6789” or maybe “1234”?
At first I thought somehow that platform they lower had a platform type of a scale that could get the weight of the fish that are slid onto the platform.
I could not find ay evidence of that, so I assume they are using a formula to estimate the weight.
If the fish is dead it can be hauled up on a crane scale and weighed accurately. That is not the case with these live sharks.
They probably used a formula based on the dimensions of the fish.-Tom