Teca was one of the names that the pre-Columbian indigenous people had for the Gulf archipelago. It includes the Islands and the Keys between the mangroves of the mouth of the Guascorán River and the Zacate Grande Island, it includes: Garrobo or San Carlos Island, Conejo Island, Garrobito Island, El Coyote Island, Inglesera or Verde Island, Violin Island, Sirena Island and Isla Exposicion the largest, distributed in an area estimated at 35 km2, on the beaches of these small islands hawksbill sea turtles and golfitas come to spawn.
The 1.5 km2 Garrobo Island is inhabited by a small group of fishermen and the 2.5 km2 exhibition island is temporarily occupied. Both are the largest of the group. Sirena Island, the smallest, is just a large spherical rock with difficult access except for a small cave-shaped entrance. Its name originates from a local legend.