Problem
Endemism (being native to and confined to an area) in Hawaiian marine gastropods varies by family. For instance, for cowries (Family Cypraeidae), 18 of the 33 species of cowries in the Hawaiian Islands are endemic (54.5%); however, for cone snails (Family Conidae), only 5 out of 35 species of cone snails in the Hawaiian Islands are endemic (14.2%), and the rest are found here in Hawaii, as well as the Indo-Pacific.
What might be keeping the number of endemic species of cone snails low? Explain.