-226 Feet Below Sea Level

At the Salton Sea, with thousands of dead tilapia washed ashore from an interesting combination of forces, killing the fish (according to an article I read). The dead fish, mixed with the high salinity of the water, and the strong west winds made for a nice stench.

Around 1996, tilapia began to die mysteriously by the thousands. On August 4, 1999, the number of fatalities reached its record of more than 7.6 million fish per day. [3] Millions of rotting fish carcasses floated across the water's surface or were strewn along the beaches. In the past large numbers of tilapia, which cannot survive in water cooler than fifty-five degrees Fahrenheit, had died due to fluctuations in water temperature. However, scientists ruled out the possibility of a temperature drop for this particular incident.

Eventually, this die-off event was attributed to eutrophic conditions caused by periodic algal blooms that are stimulated by nutrient-rich agricultural runoff containing excess amounts of nitrogen and phosphorus found in industrial grade fertilizers. During the eutrophic process, microscopic algae deplete the oxygen in the water as they die and decompose. The result is an anoxic state where breathable oxygen is present only in the first inch of surface water. During this process fish simply drown with their decomposing flesh adding to the water’s already overburdened nutrient load, thus perpetuating a unrelenting of cycle of death. This process periodically overwhelms the entire ecology of the Salton Sea, especially during hot summer months, creating a prime habitat for botulism and other bacterial infections. [4] When fish harboring the botulism bacterium sicken and die they rise to the water’s surface. Fish-eating birds then consume the diseased fish spreading the botulism outbreak among the avian popualtion causing a related cycle of bird deaths.