Endogamy, spouse origins and inbreeding in a parish of the Ebro Delta (Spain)

The Ebro Delta is an area located in the south east of Catalonia (Spain), b etween Barcelona and Valencia. In the past it was sparsely populated owing to the environmental conditions (flooding, health risks etc.), and it has b een permanently and extensively inhabited only since the canalisation of th e area (19th c.). Endogamy, origins of spouses and inbreeding estimated by isonymy have been determined from the birth registers of the parish of Sant Miquel in the village of La Cava (Deltebre), located in the centre of the Ebro Delta. The study period was 1879 to 1925 and included the year of the official start of the massive colonisation of this side of the river in 191 1. Endogamy has been found to be 81.4% for the spouses, 81.7 % for the pare nts of the husband and 84.8% for the parents of the wife. Inbreeding determ ined by isonymy was F = 0.011. These values are the highest when compared w ith other isolated Spanish and Portuguese populations.