17 Jun Choro Zapato: A resilient ally for aquaculture in the face of climate change
A recent study by the Millennium Institute SECOS and Universidad Adolfo Ibáñez (UAI) analyzed the remarkable abilities of the choro zapato—also known as the giant mussel—to adapt to the impacts of climate change, positioning it as an attractive and nutritious alternative for national aquaculture. Researchers highlight its notable capacity to thrive under extreme ocean conditions, which sets it apart from other bivalve species under cultivation.
This endemic bivalve, of great ecological and economic importance, is widely distributed along the Chilean coast—from southern Peru to Tierra del Fuego. The choro zapato grows rapidly, thrives in a variety of habitats, and is harvested by artisanal fishers along much of the Chilean coast, mainly for domestic consumption. The species is also cultivated on a small scale in certain areas between the Biobío and Magallanes regions.
Like other species, however, its cultivation could be affected by global change factors such as rising ocean temperatures, acidification, pollution, and increased frequency of coastal upwelling events. These events bring cold, low-oxygen, nutrient-rich waters from the deep ocean to the surface, directly impacting coastal biodiversity and aquaculture.
In response to this, a recent study by researchers from the Millennium Institute for Coastal Socio-Ecology (SECOS), Universidad Adolfo Ibáñez, and other institutions—published in Aquaculture Reports—analyzed the ability of choro zapato (Choromytilus chorus) to adapt to warmer and more acidic ocean scenarios.
“The study showed that choro zapato can adapt well to climate change impacts such as ocean warming and acidification, thanks to its high physiological and morphological plasticity. Moreover, its physiological capabilities align well—at least initially—with the challenges that mollusk farming may face in southern Chile,” says Marco Lardies, co-author of the paper, professor at the School of Liberal Arts at UAI, and SECOS researcher.
Resilience and Market Potential
To assess these effects, specimens were collected in Laraquete, from a small-scale aquaculture site in the Gulf of Arauco. In this area, farmed mussels are regularly exposed to coastal upwelling events that bring cold, low-pH, corrosive waters to the surface—conditions that affect their shell structures. The area is also subject to environmental pollution from local human activities.
“For the lab experiments, we simulated seasonal conditions specific to this area. For instance, in summer, when temperature and pH are higher; in winter, when pH is high and water is cold; under upwelling conditions, when water is cold and pH is low; and finally, under a projected future scenario with even more acidic and warmer water. In this way, we integrated current local characteristics and expected future conditions,” explains Cristian Vargas, professor at the Faculty of Environmental Sciences at Universidad de Concepción, SECOS researcher, and co-author of the paper.
One of the study’s most striking findings was that individuals adjusted their metabolism to compensate for environmental stress. Despite increased energy demands under warmer and more acidic conditions, they managed to enhance their filtration and nutrient absorption capacity.
“What we observed in the experiments is that they are quite tolerant to these conditions. However, more research is needed to understand exactly what makes them so tolerant. We found that they are capable of withstanding extreme conditions and show great potential for adaptation to climate change,” emphasizes Vargas.
The study also highlights the importance of continuing research on species with high adaptive potential, especially in regions like southern Chile, where environmental variability is significant.
According to the authors, the results were surprising: despite the higher energy demands in adverse environments, the mussels maintained growth and shell formation without experiencing mortality. This resilience suggests that the species could become a viable option to diversify mussel farming in Chile under challenging ocean conditions.
“Unfortunately, the lack of strong international markets—largely due to negative consumer perceptions about the color of its flesh—has kept this species from being produced at scale. But it is crucial to explore resilient marine species like choro zapato and integrate them into farming systems, incorporating innovation to leverage their large size and high nutritional quality. This strategy could help secure mussel production in a future marked by climate instability,” concludes Lardies.