Paralytic Shellfish Toxins in Surf Clams Mesodesma donacium during a Large Bloom of Alexandrium catenella Dinoflagellates Associated to an Intense Shellfish Mass Mortality

Abstract

In late February 2016, a harmful algal bloom (HAB) of Alexandrium catenella was detected in southern Chiloé, leading to the banning of shellfish harvesting in an extended geographical area (~500 km). On April 24, 2016, this bloom produced a massive beaching (an accumulation on the beach surface of dead or impaired organisms which were drifted ashore) of surf clams Mesodesma donacium in Cucao Bay, Chiloé. To determine the effect of paralytic shellfish poisoning (PSP) toxins in M. donacium, samples were taken from Cucao during the third massive beaching detected on May 3, 2016. Whole tissue toxicity evidence a high interindividual variability with values which ranged from 1008 to 8763 μg STX eq 100 g−1 and with a toxin profile dominated by GTX3, GTX1, GTX2, GTX4, and neoSTX. Individuals were dissected into digestive gland (DG), foot (FT), adductor muscle (MU), and other body fractions (OBF), and histopathological and toxin analyses were carried out on the obtained fractions. Some pathological conditions were observed in gill and digestive gland of 40–50% of the individuals that correspond to hemocyte aggregation and haemocytic infiltration, respectively. The most toxic tissue was DG (2221 μg STX eq 100 g−1), followed by OBF (710 μg STX eq 100 g−1), FT (297 μg STX eq 100 g−1), and MU (314 μg STX eq 100 g−1). The observed surf clam mortality seems to have been mainly due to the desiccation caused by the incapability of the clams to burrow. Considering the available information of the monitoring program and taking into account that this episode was the first detected along the open coast of the Pacific Ocean in southern Chiloé, it is very likely that the M. donacium population from Cucao Bay has not had a recurrent exposition to A. catenella and, consequently, that it has not been subjected to high selective pressure for PSP resistance. However, more research is needed to determine the effects of PSP toxins on behavioral and physiological responses, nerve sensitivity, and genetic/molecular basis for the resistance or sensitivity of M. donacium.

Saxitoxin Group Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity > 8000 μg STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of STX-group toxins, and of inflammatory responses detected in the digestive glands [ 33 , 35 ].…”

Saxitoxin Group Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity > 8000 μg STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of STX-group toxins, and of inflammatory responses detected in the digestive glands [ 33 , 35 ].…”

Oxidative Stress Parameters and Morphological Changes in Japanese Medaka (Oryzias latipes) after Acute Exposure to OA-Group Toxins

“…In aquatic organisms, exposure to these pollutants can be analyzed by cellular, molecular, physiological and/or biochemical biomarkers [ 26 , 27 ]. Thus, the route and level of acute or chronic exposure will define the effects they may produce on biological organisms, such as changes in the community or population of specific aquatic organisms [ 59 , 60 ].…”

Paralytic Shellfish Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity >8000 g STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of PST, and of inflammatory responses detected in the digestive glands [33,35].…”

Saxitoxin Group Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity > 8000 μg STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of STX-group toxins, and of inflammatory responses detected in the digestive glands [ 33 , 35 ].…”

Oxidative Stress Parameters and Morphological Changes in Japanese Medaka (Oryzias latipes) after Acute Exposure to OA-Group Toxins

“…In aquatic organisms, exposure to these pollutants can be analyzed by cellular, molecular, physiological and/or biochemical biomarkers [ 26 , 27 ]. Thus, the route and level of acute or chronic exposure will define the effects they may produce on biological organisms, such as changes in the community or population of specific aquatic organisms [ 59 , 60 ].…”

Paralytic Shellfish Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity >8000 g STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of PST, and of inflammatory responses detected in the digestive glands [33,35].…”

Saxitoxin Group Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity > 8000 μg STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of STX-group toxins, and of inflammatory responses detected in the digestive glands [ 33 , 35 ].…”

Oxidative Stress Parameters and Morphological Changes in Japanese Medaka (Oryzias latipes) after Acute Exposure to OA-Group Toxins

“…In aquatic organisms, exposure to these pollutants can be analyzed by cellular, molecular, physiological and/or biochemical biomarkers [ 26 , 27 ]. Thus, the route and level of acute or chronic exposure will define the effects they may produce on biological organisms, such as changes in the community or population of specific aquatic organisms [ 59 , 60 ].…”

Paralytic Shellfish Toxins Accumulation Induces Antioxidant Responses in Tissues of Mytilus chilensis, Ameghinomya antiqua, and Concholepas concholepas during a Bloom of Alexandrium pacificum

“…The above was evidenced in 2016 by the first oceanographic extension of an algal bloom associated with Alexandrium catenella towards the coast of Cucao (Chiloé, Chile), where a massive beaching of surf clams Mesodesma donacium was produced (toxicity >8000 g STX equiv 100 g −1 ). The results indicated that such environmental damage was the result of an indirect effect of PST, and of inflammatory responses detected in the digestive glands [33,35].…”