Effects of the Marine Biotoxins Okadaic Acid and Dinophysistoxins on Fish

Mauro Corriere,Lucía Soliño,Pedro Reis Costa

doi:10.3390/jmse9030293

Abstract

Natural high proliferations of toxin-producing microorganisms in marine and freshwater environments result in dreadful consequences at the socioeconomically and environmental level due to water and seafood contamination. Monitoring programs and scientific evidence point to harmful algal blooms (HABs) increasing in frequency and intensity as a result of global climate alterations. Among marine toxins, the okadaic acid (OA) and the related dinophysistoxins (DTX) are the most frequently reported in EU waters, mainly in shellfish species. These toxins are responsible for human syndrome diarrhetic shellfish poisoning (DSP). Fish, like other marine species, are also exposed to HABs and their toxins. However, reduced attention has been given to exposure, accumulation, and effects on fish of DSP toxins, such as OA. The present review intends to summarize the current knowledge of the impact of DSP toxins and to identify the main issues needing further research. From data reviewed in this work, it is clear that exposure of fish to DSP toxins causes a range of negative effects, from behavioral and morphological alterations to death. However, there is still much to be investigated about the ecological and food safety risks related to contamination of fish with DSP toxins.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The main drivers are attributed to natural environmental factors, climate change, and anthropogenic activity represented by sources of nutrients such as sewage and animal wastes, agricultural and fertilizer runoff, as well as the growing aquaculture industry in coastal areas [3,4,5]
With the number and size of mussel production platforms increasing throughout several coastal areas, and considering that mussels as shellfish species are prone to accumulate marine biotoxins such as okadaic acid [10,11,12], it is relevant to study the impact of implementing these structures on the environment in terms of availability of toxins to the surrounding food web

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. With the number and size of mussel production platforms increasing throughout several coastal areas, and considering that mussels as shellfish species are prone to accumulate marine biotoxins such as okadaic acid [10,11,12], it is relevant to study the impact of implementing these structures on the environment in terms of availability of toxins to the surrounding food web. Okadaic acid (OA) and related toxins are commonly abundant and frequent groups of marine toxins in southern Europe, Asia, and South America [14] These toxins accumulate to a great extent in bivalve mollusks, recurrently reaching high concentrations in tissues of certain species like mussels that can remain contaminated for long periods of time [11,15]. The aim of this study is to raise attention concerning the exposure of fish to the abundant and commonly available DSP toxins by gathering and summarizing the data dispersed in the literature about bioaccumulation and effects of OA-group toxins in fish and discussing their ecosystem-wide impacts

Okadaic Acid-Group Toxins

Field Observations

Investigation of OA Effects Using Zebra and Medaka as Fish Models

Research Clues from the Freshwater Environment

Final Considerations