A 67-year-old Texas man died on Tuesday morning in Tomales Bay as he and four other men, a group of friends and family, started diving for abalone, said Point Reyes National Seashore spokesman John Dell’Osso. The men, including Gerald McGuire of El Paso, launched a boat from Lawson’s Landing a little after 8 a.m. They disembarked close to the western shore of the bay and started swimming toward their chosen diving spot. But one of the men looked back and saw Mr. McGuire floating, not swimming. Realizing he was unconscious, the men pulled him onto rocks on the beach—directly across the bay from Lawson’s—and attempted C.P.R. Just after 9 a.m. one of them called 911 and another decided to retrieve the vessel. “One individual decided to swim back to the boat, bring it closer to shore, put this man on the boat and head back to Lawson’s Landing,” Mr. Dell’Osso said. The group encountered paramedics with Marin County Fire Department on the way and moved the man to the other boat, which ferried Mr. McGuire back to shore as medics continued trying to revive him. When they arrived at the landing, Mr. McGuire was moved to an ambulance and shortly thereafter declared dead. Although it appears he fell unconscious while swimming to the dive site, no official cause of death has been released. Since the abalone season opened on April 1 along the state’s coast, five abalone divers and one rock picker have died, according to news reports in Sonoma and Mendocino. The last person to die in Tomales Bay was Nick Anast, a 55-year-old life sciences professor at Santa Rosa Junior College, whose kayak capsized near Dillon Beach in March.