From Islapedia

BARRETT, Thomas (1929-1990) [SS#448-28-3238], Oklahoma attorney who fell to his death at Pelican Bay on Santa Cruz Island during a public day trip sponsored by The Nature Conservancy and operated by boat concessionaire, Island Packers, Inc. out of Ventura, California. Mr. Barrett strayed from the group-led nature hike when he fell from a rugged bluff into the water below.

His was the first casualty experienced by The Nature Conservancy since it took over the island from the Santa Cruz Island Company in 1987, and the first casualty experienced by Island Packers in 24 years of transporting the public to the Channel Islands.