Research on palm ruff fish Chilean and American scientists collaborate on diversification of aquaculture in Coquimbo Region, Chile

Cojinoba, or palm ruff fish.

Scientists from the Centro de Estudios Avanzados en Zonas Áridas (CEAZA)’s research center, Universidad Católica del Norte (UCN), (Chile) and Mississippi State University (United States), are working together to understand the physiology of cojinoba, or palm ruff fish, as a part of a collaborative project to help provide necessary information for future commercial production of this native Chilean fish. This project also integrates local fishers, allowing them to experience fish farming at a small scale.

“We are analyzing cojinoba oxygen intake to determine its normal metabolic rate, and determining fish swimming capacity, which allows us to measure its maximum metabolic rate. Importantly, we are comparing this information together with the internal responses of cojinoba to oxygen diminishing events or hypoxia in the ocean”, says Dr. Claudio Álvarez, one of the CEAZA’s researchers in the project.

Dr. Álvarez explains that the current project builds upon previous efforts of researchers at the Universidad Catóilica del Norte, who began the scientific investigation of cojinoba more than a decade ago. Dr. Alfonso Silva and Dr. Héctor Flores, both from UCN, were the first to establish culture techniques for the species.

“The knowledge that we are getting from this research is a valuable tool to set aspects like the water turnover rate and the maximum density in the fish hatchery”, adds Álvarez.

Dr. Peter Allen, associate professor and specialist on fish physiology at Mississippi State University, indicates that the breeding process of the cojinoba is already well known, from spawning through the larval state. Dr. Allen indicates that the last period of the growing process of the fish is quite difficult to reach, especially to feed it and then turn it into a saleable product for the region.

“The cojinoba is an endemic Chilean fish, which is important for producers who keep the fish in cages for grow-out to market size. Also important is the high price of the fish in the market (US $ 7, approx, in Chilean market). Aquaculture of this marine species will benefit both domestic regional and distant markets, and allow for market diversification”, says professor Allen.

From the nutritional perspective, Allen highlights the cojinoba has a low energy demand from its own habitat, which he considers an environmental advantage.

“The cojinoba embodies many positive qualities from an aquaculture perspective, and it looks good, which is relevant as well, because people want to eat something that is appealing. We know a lot about how to breed this fish, how they behave in groups, which is important in aquaculture, because many species are not used to being close to each other, whether in a natural environment or an aquaculture tank or grow-out cage”, asserts Dr. Allen.

International collaboration

Left to right, Dr. Claudio Álvarez (CEAZA) and Dr. Peter Allen (Mississippi State University).

Dr. Peter Allen’s residence in the Coquimbo Region, Chile, will extend until December 2019. Thanks to a U.S. Fulbright scholarship, he is collaborating with Dr. Álvarez and other researchers on the cojinoba fish study.

“Through my specialty in physiological ecology, I try to understand how an organism functions and use this knowledge to understand how it lives in its environment. We are using physiological tools as guidelines to develop optimal aquaculture practices for this species. Also, this information can help to develop tighter relations between companies, the government and academia ”, points out the researcher.

“Dr. Allen’s experience helps us to understand what will happen with this species in the context of climate change. This way, we can know what will occur with these organisms when they face low oxygen concentration events in the ocean. So, for this purpose we are trying to recreate such conditions, in an experimental model, which is an important parameter for future aquaculture farmers, who will work with this kind of fish”, Dr. Álvarez explains.

The low oxygen concentration events have already been detected in the ocean along the north coast of Chile and, little by little, they are getting closer to the southern Chilean sea.

Currently, cojinoba utilized in this research are being farmed at the UCN hatchery facilities. Thanks to another project at UCN, juveniles of the fish (between 120 and 200 grams each) are provided to local fishers, who have initiated their own farming of this fish, on a small scale. Scientists expect that the advances in the research will boost the interest of larger-scale aquaculture companies in the culture of this species in the next decade.