Timothy Means , a conservationist who was on the leading edge of ecotourism in the Gulf of California and helped win permanent protection for hundreds of islands off the Baja Peninsula in Mexico, died on Aug. 13 at a hospital in San Diego. He was 75.

His son, Carlos , said the cause was complications of diabetes.

Mr. Means was immersed in the natural world for most of his life. He spent decades working to protect the fragile desert ecosystem of Baja and the Gulf of California, also known as the Sea of Cortez, a body of water so teeming with life that Jacques Cousteau called it “the world’s aquarium.”

Inspired by environmentally conscious tourism on the Galápagos Islands, Mr. Means set up Baja Expeditions in 1974. It was one of the first major low-impact nature tourism companies in Mexico.

The remote southern Baja Peninsula is a region of rough, pristine beauty, with abundant flora, fauna and marine life. Mr. Means derived enormous pleasure from showing it off to groups of 15 to 20 tourists at a time, many of whom became donors to his nonprofit projects to help keep the area under federal protection.