Determination of Cylindrospermopsin Cyanotoxin in Shrimp Cultures in the Estuary of the Chone River, Pacific Coast of Ecuador

Raphidiopsis raciborskii is a filamentous bloom-forming cyanobacterium, considered as a cosmopolitan species. Some strains of R. raciborskii are capable of producing toxins, e.g. cylindrospermopsin (CYN) that greatly threatens human health. One of the most studied cyanotoxins is CYN, and is receiving increasing scientific attention due to its global distribution, bioaccumulation, and multiorgan toxicity. The development of Cyanobacterial blooms of R. raciborskii is attributed to high amounts of nutrients (e.g. phosphorus and nitrogen) in the water of shrimp culture ponds. Metabolic activities of cyanobacteria in the blooms cause release of CYN which can deteriorate the flavor and protein content of the crustaceans in the culture ponds, subsequently affecting export quality. The objective of this work was the identification of the CYN in water samples obtained from culture pools and of shrimp (Penaeus vannamei) samples by Ultra-high performance liquid chromatography (UHPLC). Sampling was carried out in shrimp ponds located in different sectors (i.e. Portovelo, Barquero and kilometer 21) of the Chone river estuary Ecuador for a period of 7 months (i.e. October 2023-April 2024). The highest CYN concentrations observed at the sectors Portovelo (left bank of the Chone river estuary), kilometer 21 and Barquero were 1,158, 517 and 489 µg/L, respectively. On the other side, the CYN concentration in intestine and muscles of shrimps collected at three different sectors were as follows – Portovelo: 1,130 and 1,291 µg/L; Barquero: 1,084 and 450 µg/L; Kilometer 21: 1,058 and 380 µg/L, respectively. These results suggest that CYN contamination was not just limited to water (of shrimp culture ponds), but extended up to shrimp tissues by bioaccumulation; which threatens ecological and human health risks posed by CYN. Cylindrospermopsin (CYN) was detected in water and shrimps from shrimp pools. CYN values in water and shrimp muscle and intestine were found to be high. Human health at risk from possible CYN toxicity and disease was explored. Control and monitoring of CYN in harvested shrimp are greatly warranted.