Some scholars think that the designation Vezo relates solely to the way of life of fisher populations along the southwestern coast of Madagascar. Yet both Vezo and migrant fishers occupy this space. Prohibitions on sheep observed by all Vezo lineages of the Fihereña coast illustrate a "Vezoization" of these immigrants. Furthermore, the myth of the "Mere-Sirene," Ampelamananisa, supports their identity construction. The Vezo environment includes both marine and terrestrial areas. The patriarch, the ritual pole holder, draws political and religious power by asking help from the ancestors. Today, fishing intensification and destructive capture techniques threaten to unbalance the Vezo world. Nevertheless, the process of forming a Vezo ethnic group is ongoing and merits multidisciplinary research.