The poor water quality resulting from different sectors of tourism has ultimately threatened the aquatic ecosystem in state of Quintana Roo. The aquatic environment of the Nichupte lagoon system has been already deteriorated so badly that tourism agency was forced to run several barges to clean the lagoon by collecting the algae and other wastes. The explosion of algal growth has severe implications on levels of dissolved oxygen and light penetration, which in turn govern fish numbers, species composition and growth rates as well as aquatic plant and other marine animal life (Zarate Lomeli et al., 1999). The commercially valuable fishing stocks, e.g. lobsters and conch, have been declined due to the intense fishing levels employed to meet the increasing sea food demand from tourists. Others species, such as sea turtles, have also been affected by the tourism and associated population growth. Marine species such as sea turtles and their eggs are used as a food source, despite the fact the Mexican government had declared a permanent ban on harvesting these animals in the Pacific, Caribbean, and Gulf of Mexico (Trejo, 2003). Now days, the turtles face a new threat i.e. continued construction of tourism facilities in sensitive egg laying areas on coast. In addition to turtles, more than ten species of sea birds are still hunted, along with four species of marine mammals (Juarez, 2002; Romero, 2009).
The discharge of inadequately treated waste water effluent has introduced hazardous pathogens into aquatic environment potentially affecting the coral growth. The introduction of nitrogen and phosphorus containing effluent expedites the process of eutrophication and abundant growth of algae. The tourist facilities and concreted areas increase the amount of impervious surfaces, causing more runoff of nutrients, suspended particles, and oil and gas into water bodies. It results in acceleration of the eutrophication process i.e. an over growth of algae. Further, the overgrowth of algae is accompanied by the depletion of oxygen resulting in extinction of fishes (Cesar Dechary & Arnaiz Burne, 1996). The overgrowth of algae is also a nuisance to swimmers. Furthermore, if masses of algae wash up on shore, they can create a foul-smelling area and a breeding ground for biting flies. The overgrown algae cover the filter-feeding corals, hampering their ability to get food. Additionally, the overgrowth of algae impedes the sunlight that normally reaches to the plant cells (zooxanthellae) living within the corals’ tissue, hindering their ability to grow and provide the coral with needed nutrition, ultimately resulting in stressed and decreased growth (Romero, 2009).
Recreational boats and cruise vessels can also physically damage aquatic vegetation by cutting it with their propellers in shallower areas. Anchoring on the reef system itself can create a significant damage to the coral reef (Salazar Vallejo et al., 1993). The extraction from the coral reef system associated with the tourism industry has also increased. The levels of toxicity in waters has increased from the petrol used in recreational vehicles and coupled with the effects of detergents and trace elements from the decomposition of tins and bottles are also harmful to aquatic plants and wildlife. Given the porous nature of the substrate, and untreated residual water discharge, there has been some bacteriological contamination of potable water bodies in Quintana Roo (Zarate Lomeli et al., 1999; INEGI, 2009). Needless to say when eutrophication, sedimentation and such matters are evident, coastal recreational waters are not aesthetically attractive and the resource is visually perceived as degraded.