Was at Basspro shops today and noticed a new/different kind of measuring device (kinds of pink in color) that you can drop the crappie into and it measures it and tells according to how long it is how old the fish is. 13inch fish said it was 7-8yrs old. How accurate is this? And I have never heard this mentioned before in dissusion by anyone. Anyone may reply please if you have any knowledge of length= yrs/age of fish. thanks