Bacalar Lagoon

Landscape and ecology

The lagoon is a karst system: groundwater is its main source, and the northern basin has muddy sediments and turbid water while the south has sandy bottoms and clearer water ². Its microbialites stretch for about 10 km in the south, where groundwater of suitable chemistry discharges ². UNAM researchers report that they grow about a millimetre a year, that some are more than 9,000 years old, that each can host thousands of microbial species, and that records show them degrading ³. Earlier UNAM work attributed damage to knocks from tour boats and rising nutrient levels in the water ⁴.

The 2020 colour change affected about 66% of the lagoon and marked a shift from nutrient-poor to nutrient-rich conditions ². The authors of that study name deforestation, shoreline change and urban growth as possible drivers that need further research ². UNAM researchers also point to high nitrogen and ammonium levels and to sediment, pesticides and fertilisers washed in from farmland ³.

Culture and heritage

The town's landmark is the Fuerte de San Felipe, built in 1733 on the orders of the governor of the Captaincy General of Yucatán to check English settlement on New Spain's southern frontier and to guard against pirates and logwood raiders ⁵. In 1858, during the Caste War (which INAH calls the Guerra Social Maya), Maya rebels took the fort and the mestizo and criollo population fled to what is now northern Belize ⁵. In 1936 the federal government resettled the town, then called Villa de Salamanca de Bacalar ⁶. INAH was repairing a section of the fort's moat wall in late 2024 after heavy rains in June that year ⁵. We have not found sources in which present-day Maya residents describe their own relationship with the lagoon.

Communities and livelihoods

Bacalar became a municipality in its own right in 2011 ⁶. Sanitation has lagged behind settlement: a 2021 report found that around 13,800 homes depended on septic tanks, that only about 200 of some 1,000 enabled sewer connections were in use, mainly by hotels, shops and restaurants, and that seepage reaches the lagoon ⁷.

Who should govern the lagoon is contested. A proposal for a protected natural area covering the Bacalar–Chetumal lagoon system has been opposed by business groups, including the regional hotel association, and by several ejidos and lakeshore landowners. One biologist quoted in the debate argued that protecting only the lower basin makes little sense while sediment, agrochemicals and polluted groundwater come from upstream ⁸.

Tourism model and development

Researchers describe Bacalar's emergence as an international destination as disordered and without clear urban development plans ², and UNAM scientists say tourism demand is growing without the infrastructure to manage waste and wastewater ³. The Tren Maya has added to the pressure: in July 2025 local reporting said record ridership had not been matched by improvements in drainage and wastewater treatment in Bacalar ¹⁰.

Regulation is arriving piecemeal. In November 2025 the Chetumal–Bacalar harbour master presented navigation rules dividing the lagoon between Bacalar and Los Rápidos into five zones with speed limits from 7.4 km/h to 37 km/h, and restricting areas such as Los Rápidos and the Canal de los Piratas to authorised boats; at that point the rules had not yet been published in the official gazette ⁹.