CNN  — 

No trace of an Australian diver has been found more than 24 hours after what police believe was a fatal great white shark attack on Sunday.

Gary Johnson is believed to have been attacked by a great white shark while diving near Cull Island, off Esperance on the south coast of Western Australia. Johnson was president of the local dive club, according to the Esperance Dive Club.

“No parts or remains have been found, and the search is ongoing,” Esperance Police Sgt. Allan Keogh told CNN.

Johnson’s wife, Karen Milligan, witnessed the attack and was taken to the hospital to be treated for shock, CNN affiliate 7 News reported.

“Gary was my rock,” Milligan said in a statement. “He was a kind, gentle, strong man. He only ever saw the best in people. He will be so truly missed by me, by his family and his friends and the world will be a poorer place without this most beautiful man.”

The attack happened hours after a reported shark sighting in the area.

“Preliminary information suggests the victim of the shark attack was in the area on a boat. It is believed the victim was diving at the time,” police said in a statement.

Esperance Police and marine rescue volunteers were deployed to search the ocean for the victim.

People have been advised to take additional caution in the water following the incident. Shark warning signs have been placed along the coast and piers.

“He and I were at home in and on the ocean,” Milligan said. “We would go out diving in our boat whenever we could, most weekends. We took photos, not fish. We were always aware of the risks, and often told each other that if we were attacked by a shark, that would just be unlucky. We were completely against shark culling, and I still am.”

Great white sharks have been responsible for approximately 40% of shark attacks off the Western Australia caost since 1980, and cause more serious and fatal bites than any other shark species, according to Sharksmart, a government information service.

Milligan said both she and Johnson believed if fish stocks were “better protected,” the risk of sharks to people in the waters would be reduced. Johnson had also dreamed of having a Marine Park in the Esperance area, according to his wife.

Esperance is located about 720 kilometers (447 miles) southeast of the state capital, Perth, and is a popular spot for diving.

Sunday’s incident marks the second fatal attack in the area in the past three years. In 2017, 17-year old Laeticia Brouwer was fatally injured when surfing with her father a few kilometers from Esperance.

There were two non-fatal shark bite incidents off Western Australia in 2019, a spokesperson for the Department of Primary Industries and Regional Development told CNN.