Hopes were fading on Saturday of finding more survivors among about 50 people missing and feared dead after two boats carrying illegal migrants, most of them from the Dominican Republic, sank this week in separate incidents in the Caribbean. Haitian and French authorities reported that they had found 31 bodies so far from the wrecks - which took place off the southwestern coast of Haiti, and off the coast of the small Franco-Dutch island of St. Martin. The double tragedy highlighted the perils of voyages in often small and overcrowded vessels that hundreds of people from poorer Caribbean nations make every year to seek a better life in more prosperous parts of the region.