...If you dive in the mid west like @KathyV watch out for "blue gills" -- But we do appreciate you concern and posting...
Thanks but I do NOT dive in the Midwest, it's much too cold for me! And I have not dived in California either for the same reason. The nearest I have come to California diving has been liveaboards in the Sea of Cortez and Hawaii - much warmer and not very near but there were some sharks.
The greatest numbers of sharks I have seen while diving have been in Florida, the Bahamas, the Turks and Caicos, and the Red Sea. The first time I saw sharks while diving I was amazed at how beautiful they are - I had seen Hollywood images of "terrifying killers" but they are lovely to watch, from a distance, and they truly are the masters of the reef. When we were younger we went on a shark feeding dive in the Bahamas so I've also seen a large group of sharks in a feeding frenzy - and it was kind of scary.
I do enjoy the sun and surf of the beautiful California beaches so maybe someday I will put on a 7mm wetsuit and don a lot of weights and try diving in California - or maybe not - and maybe someday you will try wreck diving in the Great Lakes - or maybe not!
I have not offered any speculation about this attack because I don't know anything, and I've never dived for lobsters because that is not of interest to me, but I have posted links to some articles claiming to have information about the event because I am interested in the ocean and sea creatures and diving.
I've noticed that some of the reporters used the phrase "brutally attacked" in describing the incident which isn't correct IMO. I am very sorry for the boy and his family and I hope never to suffer any traumatic injuries of any kind, but I don't think that the shark was being brutal - it was just being a shark. I've noticed that none of the reporters said that the lobsters were being "brutally attacked" by the divers.
We will be heading out on a dive trip to the Caribbean soon, very warm and easy and not many sharks, but as you say "Sharks are an occupational hazard of diving in the ocean" and we are likely to encounter at least a few.
I am very sorry about your friends, were you present during any of the attacks? How awful that must be for everyone involved. My sympathies for this young, handsome boy and his family; it is great that he is expected to recover but it won't be easy.