He lived in San Diego, came to a couple SD Reefs events back in the day, it was a big deal, this was the person to talk to for hours. Spoke at several SDMAS events if I recall.
With all this Covid nonsense his passing was lost.
https://www.reef2rainforest.com/2020/05/08/robert-m-fenner-1952-2020/
https://reefbuilders.com/2020/05/08/bob-fenner-will-forever-be-missed/#
http://www.wetwebmedia.com/WWMAdminSubWebIndex/bobfbio.htm
RIP