Specialist urged to monitor red tides in the country

Eirinet Gómez

La Jornada Newspaper, Wednesday, June 25, 2025, p. 5

In Mexico, it is urgent to implement constant monitoring of red tides because, while most of them are not toxic, some are and can affect both marine fauna and humans. Among other effects, they cause paralysis, respiratory problems, damage to the nervous system, and gastrointestinal symptoms, even death , Yuri Okolodkov, a researcher at the Institute of Marine Sciences and Fisheries at the University of Veracruz, explained to La Jornada .

The specialist explained that measures must be established to control nutrient discharges in coastal areas "to protect both marine biodiversity and economies that depend on the sea, since the discharge of untreated water with high nutrient concentrations into the sea is directly related to the increase in red tides."

“The discharge of nitrates, nitrites, ammonium, urea, and phosphates into the oceans generates a process of eutrophication, in which excess nutrients cause uncontrolled growth of planktonic microalgae, which favors the emergence of this phenomenon.

The massive proliferation of microalgae in bodies of water often turns the sea red, brown, green, or yellow, depending on the algae species present. Those that don't release harmful toxins can cause environmental problems, such as a decrease in oxygen in the water, leading to the death of fish and other marine life , he noted.

Okolodkov emphasized that the increase in red tides in recent years is anthropogenic, meaning it is linked to human activities such as intensive agriculture, wastewater discharge, and industrial pollution.

This relationship between pollution and algal blooms, he added, has been documented by researcher Gustaaf M. Hallegraeff, who in 2021 published a study based on data collected over 30 years. The study recorded approximately 7,000 red tide events in different regions of the world, reinforcing the need for monitoring and regulating discharges.

Regional analysis

However, the scientist clarified that the trend of increasing red tides cannot be considered global, as each region must be analyzed to detect specific patterns. We cannot speak of a uniform global trend; we must look at the specific characteristics of each region to understand how this phenomenon is evolving .

Climate change is another factor that could be driving the proliferation of red tides. Rising temperatures will affect coral ecosystems. As corals die, some species of microalgae find favorable conditions to proliferate on them , he explained.

These processes have already been recorded in the country's waters of the Gulf of Mexico and the Caribbean. According to reports from the Institute of Marine Sciences and Limnology, there has been an increase in red tides in recent years, detrimental to fishing and public health.

One of the most promising lines of research in this area is developing an early warning system. Red tides have been known for centuries, but they remain unpredictable .