Shallow-water benthic decapod crustaceans of Chankanaab Park, Cozumel Island, Mexico

Chankanaab Park is a protected area in Cozumel Island, Mexico, that includes a portion of the coral reef marine environment, and a small inland lagoon connected to the sea by a narrow underground tunnel, 60 m long. The present study is the first addressing the benthic decapod fauna in this Park. Because of the protected status and the small area of the marine zone of the Park (similar to7 ha), collections were made only by hand using SCUBA diving. Seventy-three decapod species belonging to 22 families were identified in the Park area. Twenty-one species occurred in both habitats (marine zone and lagoon), indicating that there is faunal exchange between both sites through the tunnel, either by means of larval phases, or by crawling or walking individuals. In fact, nine of these 21 species were actually recorded in the tunnel. Of the remaining species, 49 were restricted to the marine zone, and one was found solely in the lagoon. The higher species richness in the marine zone seems related to the wider variety of habitats in that area, especially living substrates such as erect sponges, octocorals, seagrasses, and anemones, which harbored a number of associated decapod species but were completely absent from the lagoon. Although no human activities are allowed in the lagoon, and fishing is forbidden in the whole Park area, the Park receives a daily average of 1000 visiting tourists, most of which conduct aquatic or underwater activities in the marine zone. Further protection of the live substrates in the marine zone is recommended, to warrant the preservation of the rich decapod fauna in the area.