More Than a Million Dead Sardines; Rodríguez Dam Contaminated
- Media
- Jan 20
- 3 min read
All waters flow to the sea and in this case, through the water shed of the Tijuana River Valley. What goes on in Mexico affects us. Pollution knows no boundary. The Rodrigues Dam Reservoir drains into the Tijuana River, which flows in a concrete channel through the city, crosses the U.S.-Mexico border, and eventually empties into the Tijuana Estuary and then the Pacific Ocean near Imperial Beach, California.
From "Zeta" news, January 12, 2026
Seven days after state and federal authorities began addressing the die-off of Maya sardines in the Abelardo L. Rodríguez Dam in Tijuana, personnel from different institutions continued removing dead specimens with a Baxter truck and burying them in the area adjacent to Esperanto Park.
Just meters from the reservoir, the smell of salt and dead fish lingered in the air, growing stronger the closer one got to the water's edge. Along certain banks near Esperanto Park, white patches were visible, the remains of fish that continued to die, as observed during a tour conducted by ZETA .
Manuel Guerrero Luna, general director of the Baja California Peninsula Basin Organization of Conagua (National Water Commission), estimated that the mortality of Mayan sardines would reach 20 tons, a figure that translates into more than one million specimens, if one takes into account that each animal of this freshwater species has a weight of between 12 and 16 grams.
Preliminary analyses—with which Conagua attributed the fish deaths to the Santa Ana winds, ruling out water pollution—suggest the opposite, according to what was explained to ZETA by biologist and researcher José Augusto Valencia of the Autonomous University of Baja California (UABC), and biochemical engineer José Carmelo Zavala Álvarez of the Center for Innovation and Environmental Management (CIGA), who agreed that the winds may have contributed, but are definitely not the primary cause of the fish deaths.
The reservoir contains a large amount of organic matter of unclear origin, as it could be due to irregular runoff of fertilizers or pesticides from agricultural areas and domestic wastewater; even from the Esperanto Park facilities themselves, if they are not connected to a pumping station to remove the waste, because at that level the drainage system is insufficient to collect it in the city's normal sewer system.
"There would have to be a pumping station to pump it upstream and connect it to the sewer system upstream, in the town of La Presa." —José Carmelo Zavala, biochemical engineer
Given that this is the first report of mass fish mortality at the Abelardo L. Rodríguez Dam since Esperanto Park began operations, the biochemical engineer considered it likely that the increased activity at the site was also a contributing factor to the mass fish mortality.
The state government would have to make public the Environmental Impact Statement for Esperanto Park, since it admitted not having done the EIS for the Laguna México park in Mexicali, he pointed out.
When questioned about where the drainage of Esperanto Park is connected, the director of the Tijuana State Public Services Commission (CESPT), Jesús García Castro, said that in Esperanto Park there is minimal infrastructure (“what they need is water to irrigate the park and the bathrooms”) and the discharge is into the network of the street in front of the entrance.
The specialists consulted by ZETA pointed out the importance of conducting an in-depth study and disseminating the results to the public, since the Abelardo L. Rodríguez Dam is a water reservoir for the city, and although it is not currently used to supply water to the population, it should be considered for future use.
...The president of the Baja California Sport Fishing Club, Alejandro Rosas Romandía, stated that the Abelardo L. Rodríguez Dam is “highly contaminated” by leaks of sewage water coming from plants in the upper part of the reservoir....
Más de un millón de sardinas muertas; Presa Rodríguez contaminada | by Julieta Aragón| January 12, 2026 | ZETA
Margaret Williamson | January 16, 2026 | Let's Talk Sewer
Fish die offs, usually caused by lack of oxygen in water. Something is using the oxygen faster than replacement, Something is going on...nutrients feeding algae blooms, the dead algae consumed using oxygen, affecting the fish. Surprised they can't find the cause.