A border dispute between Nicaragua and Costa Rica is deepening concern for two embattled marine species: the sawfish (Pristis pristis) and bull shark (Carcharhinus leucas). Officials say the countries’ continuing disagreement over Costa Rican claims to navigation rights on the San Juan River has sidetracked bilateral efforts needed to protect the animals. The sawfish are listed as critically endangered by the World Conservation Union (IUCN), and bull sharks are listed as “near threatened.” Both species migrate 70 miles (180 kms) up Costa Rica’s Colorado River into the San Juan River and on to Lake Nicaragua, one of the hemisphere’s largest freshwater lakes. In recent years, Costa Rican shark fishing near the mouth of the Colorado has taken a heavy toll on the bull shark population... [Log in to read more]