Yep judging by the damage evident in the pic this shark had a very wide mouth. Females get much larger than males. The shredding indicates violent shaking. The surge out of the water is classic seal predation behavior: hard hit at full speed.
This shark was after dinner. Other reports suggest he was swimming behind the group. That's also common: Whites pick off stragglers. Never swim alone. This shark probably stalked them for quite a while before deciding which to eat.
“Never swim alone...”
Back when I was younger and (more) stupid I scuba-dived off a big guest boat on the Great Barrier Reef. (10 minute “instruction” on scuba diving!) My friend left after 3 minutes in the water and went back to the boat. There were other swimmers in the general area, but not that I can really recall seeing any. Saw a big shark and tried to swim closer for a better look (I think I had read somewhere that if you’re not at the surface there isn’t much danger!?) Luckily it just kept swimming away from me. I guess I’ll have to wait for some other episode of life to win a Darwin Award. The giant 6-foot long clams were pretty cool too.