Tourist carrying capacity at Islas Marietas National Park: An essential tool to protect the coral community

- Carrying capacity has emerged as an management tool of natural protected areas.
- Islas Marietas has an important coral community with a high biodiversity.
- The increase in the number of visitors can compromise the natural resources.
- The CC is exceeded in specific sites which receive most of the visiting.
- Is a priority to consider the TCC as an active management tool at any coralline area.

Carrying capacity has emerged as an important parameter to consider when developing a series of effective management tools for natural protected areas such that the experience of the average tourist remains satisfactory when exerting an "acceptable" or minimum impact to the protected area. The carrying capacity is site-specific, as it considers not only human activities and management capacity, but also the environmental characteristics (both biotic and abiotic) of the area of interest. Islas Marietas National Park is a protected area with an already-established management plan that seeks to conserve and protect the coral-rich areas and all associated organisms within the park. However, there are currently no guidelines regarding the maximum carrying capacity and the limit of acceptable change. At Islas Marietas two activities, SCUBA diving and snorkeling were evaluated, and the physical carrying capacities were 417-583 dives site−1 day−1 and 720-840 snorkeling excursions per day−1, respectively; however, when using correction factors, the effective carrying capacity was reduced to 22.4-46.4 dives day−1 and 83-135 snorkeling excursions day−1. Using the annual historical tourism data, the carrying capacity of the area has not yet been reached; however, the local marine resources undergo different degrees of pressure according to the high tourism seasons, suggesting that, even if the carrying capacity has not been met, the marine environment could still be compromised at specific times. The implementation of the local carrying capacity had lead not only to maintain the balanced use of resources at Islas Marietas National Park but furthermore, combined with a other programs, to promote projects such as coral cover restoration, enhancing the relevance of the application of carrying capacity for the sustainable use at any coralline area.