This research has been focused on understanding how invasive organisms modify community structure and ecosystem processes. Specifically, I studied an invasive group of armored catfish (Siluriformes: Loricariidae) and their impacts in the Usumacinta watershed in Chiapas, Mexico. Loricariids, also known as “plecos” and “algae eaters” in the aquarium trade, are a large family of catfish. More than 700 species of loricariids have been identified and the list is still growing. They are amazing catfish native to tropical areas in South America, Costa Rica, and Panama. Unfortunately, several species of armored catfish have been introduced throughout the world.
The impacts of invading loricariids in developing countries can be especially severe on local human populations. Freshwater fishes are the primary protein sources of many people in developing areas of Latin America and Asia. The explosion of armored catfish populations in Mexico has destroyed many local fisheries. Loricariids become entangled in fishing nets and destroy them with their spines. Additionally, as armored catfish populations increase, Mexican fishermen have seen a concurrent reduction in the populations of other fishes.
The results from this work indicate grazing by loricariids reduces the quality and quantity of benthic resources and this negatively influences higher trophic levels. Additionally, intensive grazing by high-densities of loricariids results in a negative net-effect on algal biomass and primary productivity in the Chacamax River. At a larger spatial scale, these findings suggested loricariids dramatically increase the amount of nutrients stored in fish tissue and the rate at which nutrients are remineralized in fish excretion, thereby converting the river to a system where fishes are primary drivers of nutrient dynamics. This study also demonstrates invasive organisms can simultaneously function as sources and sinks of nutrients and these effects are element-dependent.
We are moving forward with projects to study community structure and ecosystem function in streams in southern Mexico. We are excited to develop new collaborations! Please feel free to contact me if you are interested in collaborating or pursuing aquatic ecology research in Mesoamerica.