Hardly a baby... a fish in that range could be 30 years old. Unfortunately the true giants, estimated to reach 800 pounds and most likely over 100 years of age, were known from the Sea of Cortez (Gulf of California).
The fact that many of these fish were gone by the 60's, and that those taken commercially and by recreational anglers often had their heads chopped off and were gutted which rendered them of minimal value for age or dietary studies, means that we have relatively little hard information about them. Given their protected status, they can't be taken for such study today (thankfully).
I've had as many as 16 swirling around me at one time as I filmed courting clusters off Catalina. I've estimated the largest one I've ever seen to be 600 pounds. Several island boat captains have seen fish in that same size range (and even named one of them Dr. Bill... which I don't think was entirely a compliment to me or the fish!).
