Determining the Exposure Pathway and Impacts of Microcystis on Threadfin Shad, Dorosoma petenense, in San Francisco Estuary

Abstract

Blooms of the cyanobacterium Microcystis spp. could affect fish health through the ingestion of colonies as well as exposure to dissolved microcystins in the water column. The goal of the present study was to evaluate the dietary exposure pathway through which Microcystis spp. blooms may affect liver function and nutritional status using a novel approach involving multiple analytical methods to assess the potential risk. Our study was conducted using threadfin shad, Dorosoma petenense, which is a pelagic fish commonly exposed to Microcystis spp. blooms in the upper San Francisco Estuary. The approach incorporated published and optimized methods that offer multiple lines of evidence including in situ hybridization, immunohistochemistry, histopathology, condition factor indices, and nutritional profiles. Measurements of threadfin shad health and tissue condition were conducted at sites where Microcystis was present or absent during the 2007 bloom season. The results showed that dietary exposure to fish from Microcystis blooms resulted in the accumulation of microcystin in the gut and liver tissues of threadfin shad collected from the sites with blooms. Although toxicity endpoints were likely confounded by antecedent conditions, our findings demonstrate dietary exposure of Microcystis toxins to fish using a novel approach with multiple lines of evidence. Environ Toxicol Chem 2020;39:787–798. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Primeros registros de un pez dorosomátido y de un parásito metazoario de peces en la laguna de Masaya, Nicaragua

“…Las especies de Dorosoma son centinelas por su sensibilidad a cambios ambientales, y algunas han servido como indicadores de contaminación por cianobacterias (Acuña et al 2020). Se considera que la mortandad de la temporada de inicio del verano puede tener una combinación de causas, entre ellas la introducción de contaminantes de una vertiente de aguas domésticas no adecuadamente tratadas desde Masaya y desechos sólidos desde varias comunidades (MARENA 2014; Figuras 3 y 4).…”

Integrative monitoring strategy for marine and freshwater harmful algal blooms and toxins across the freshwater‐to‐marine continuum

“…It is unclear to what extent emerging environmental, human, and wildlife health issues are associated with the transport of cyanotoxins to downstream receiving waters because routine, integrated watershed monitoring has been lacking. However, cyanotoxins have been shown to accumulate in aquatic food webs (Acuña et al, 2020; Bolotaolo et al, 2020; Lehman et al, 2010; Smith & Haney, 2006) and to bioaccumulate in estuarine and marine shellfish in the USA (Bukaveckas et al, 2018; Garcia et al, 2010; Gibble et al, 2016; Miller et al, 2010; Peacock et al, 2018; Preece et al, 2015; Tatters et al, 2019). Microcystins can be retained in California mussels ( Mytilus californianus ) for up to eight weeks after exposure (Gibble et al, 2016), and their persistence may increase the risk of exposure to wildlife and humans.…”

Covariance of Phytoplankton, Bacteria, and Zooplankton Communities Within Microcystis Blooms in San Francisco Estuary

“…These toxic substances and cell lysates may also alter the diversity and abundance of bacteria during blooms ( Otten et al, 2017 ; Kurobe et al, 2018a ). Microcystins occur within organisms throughout trophic levels in the food web ( Lehman et al, 2005 ) and were correlated with a decrease in the survival of zooplankton ( Ger et al, 2009 , 2010 ) and native fish ( Acuna et al, 2012 , 2020 ; Kurobe et al, 2018b ). An analysis of the planktonic communities within Microcystis blooms across trophic levels and how these change with wet and dry conditions has not been done.…”