The deaths of up to a million fish in Lake Cajititlan is sparking a bitter war of words between officials from rival political parties as experts struggle to determine whether natural causes or pollution is to blame for the ecological disaster.
Over the past week, Jalisco Environmental Agency (Semadet) employees, aided by a team of volunteers, have extracted more than 80 tons of mojarra, known locally as popocho, from the waters of the lake, located 20 miles south of Guadalajara. Tourist boat owners and even local mariachi musicians have lent a hand to remove the fish.
Over the past two years state authorities had put down smaller incidents of fish perishing in the lake to seasonal temperature variations and a reduction in oxygen levels.
This time, however, the greater numbers of fish involved prompted Semarnat to change its tune.
Semadet Director Magdalena Ruiz rejected the notion that the fish died from a "natural phenomenon" and confirmed the disaster is almost certainly related to "the degradation of the lake." Early investigations focussed on several waste treatment plants dotted around the lake shore. Some reports suggested these facilities, operated by the Tlajomulco municipal government, were not functioning optimally and could be spewing untreated sewage into the lake. Several rural communities and industries suspected of poor environmental practices are also being investigated. One report suggested that fertilizers used in cornfields adjoining the lake could have filtered into the breeding grounds of the fish.
After Ruiz insisted the fish deaths were "provoked by bad management of the lake," attention shifted to Tlajomulco Mayor Ismael del Toro, who declared the disaster to be yet another natural occurrence as soon as the fish were spotted washing up on the lake's shore.
Del Toro, who is one of only a handful of Jalisco mayors from the fledgling Citizen's Movement (MC) party, attacked state authorities for "jumping to conclusions" before investigations had begun properly.
In particular, he blasted the Institutional Revolutionary Party (PRI), whom he accused of politicizing the disaster, even suggesting that nefarious interests within the ruling party might have engineered the fish deaths for their own purposes.
PRI chiefs expressed outraged at the accusation, with one senior official noting that it "takes sick minds to think of such a thing" and that, most likely, the MC was the real guilty party.
As the federal Attorney General's Office and Jalisco Human Rights Commission pondered whether to start investigations into possible wrongdoings, Del Toro reminded journalists that the remit for maintaining the quality of Lake Cajititlan falls on the National Water Commission (Conagua) and not Tlajomulco officials.
Responding to the growing pressure at an hour-long press conference on Tuesday, Del Toro showed copies of state government documents that confirmed the recent spate of fish deaths were caused by natural phenomena, and others that he said proved the municipality's commitment to improving water quality in Lake Cajititlan.
An incident in July last year, when thousands of fish died after a processing plant in Tlajomulco dumped 10,000 cubic meters of molasses into the Valencia reservoir, has only heightened the speculation that the fish deaths were provoked by human hands. The official explanation given then was that a lack of oxygen in the water meant that the molasses, an organic by-product of the refining of sugarcane, were unable to biodegrade naturally.
With Lake Cajititlan's fish stock now decimated, Jalisco authorities have promised to support 130 fishermen to the tune of two minimum salaries per day (around 130 pesos) through December.
Meanwhile, Jalisco PRI legislators in the Chamber of Deputies called on federal agencies to investigate the possible role of Tlajomulco officials in the disaster and demanded that the "full weight of the law be brought down" if found responsible.
The trading of insults between the PRI and MC has not come as huge surprise to political observers, since the MC recently decided to break off all communication with the PRI-run Jalisco government.
The ecological disaster comes at an unfortunate time for del Toro, almost a week after an independent study found Tlajomulco to be the most transparent municipality in Mexico, along with Zapopan.