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A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 44624

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Special Issue Editor

Prof. Dr. Shauna Murray

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Guest Editor

Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia
Interests: harmful algal blooms; qPCR; phylogenetics; evolution; molecular ecology; benthic dinoflagellates; systematics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

The rapid expansion of aquaculture around the world is increasingly impacted by toxins produced by harmful marine microalgae, which threaten seafood safety. In addition, ocean climate change is leading to changing patterns in the distribution of toxic dinoflagellates and diatoms that produce these toxins. New approaches are being developed to monitor for harmful species and the toxins they produce. This Special Issue will cover new research on harmful marine microalgae and their toxins, including the identification of species and toxins; the development of new chemical and biological techniques to identify and monitor species and toxins; marine biotoxin uptake in seafood and marine ecosystems; and the distribution and abundance of toxins, particularly in relation to climate change.

Prof. Dr. Shauna Murray
Guest Editor

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Keywords

Marine harmful algae
Gambierdiscus
Alexandrium
Dinophysis
Pseudo-nitzschia
ciguatoxin
saxitoxin
okadaic acid
domoic acid
paralytic shellfish toxins

Published Papers (12 papers)

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Research

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17 pages, 2391 KiB

Open AccessArticle

Toxicity of the Diatom Genus Pseudo-nitzschia (Bacillariophyceae): Insights from Toxicity Tests and Genetic Screening in the Northern Adriatic Sea

by Timotej Turk Dermastia, Sonia Dall’Ara, Jožica Dolenc and Patricija Mozetič

Toxins 2022, 14(1), 60; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14010060 - 15 Jan 2022

Cited by 11 | Viewed by 4135

Abstract

Diatoms of the genus Pseudo-nitzschia H.Peragallo are known to produce domoic acid (DA), a toxin involved in amnesic shellfish poisoning (ASP). Strains of the same species are often classified as both toxic and nontoxic, and it is largely unknown whether this difference is also genetic. In the Northern Adriatic Sea, there are virtually no cases of ASP, but DA occasionally occurs in shellfish samples. So far, three species—P. delicatissima (Cleve) Heiden, P. multistriata (H. Takano) H. Takano, and P. calliantha Lundholm, Moestrup, & Hasle—have been identified as producers of DA in the Adriatic Sea. By means of enzme-linked immunosorbent assay (ELISA), high-performance liquid chromatography with UV and visible spectrum detection (HPLC-UV/VIS), and liquid chromatography with tandem mass spectrometry (LC-MS/MS), we reconfirmed the presence of DA in P. multistriata and P. delicatissima and detect for the first time in the Adriatic Sea DA in P. galaxiae Lundholm, & Moestrup. Furthermore, we attempted to answer the question of the distribution of DA production among Pseudo-nitzschia species and strains by sequencing the internal transcribed spacer (ITS) phylogenetic marker and the dabA DA biosynthesis gene and coupling this with toxicity data. Results show that all subclades of the Pseudo-nitzschia genus contain toxic species and that toxicity appears to be strain dependent, often with geographic partitioning. Amplification of dabA was successful only in toxic strains of P. multistriata and the presence of the genetic architecture for DA production in non-toxic strains was thus not confirmed. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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29 pages, 7221 KiB

Open AccessArticle

Update of the Planktonic Diatom Genus Pseudo-nitzschia in Aotearoa New Zealand Coastal Waters: Genetic Diversity and Toxin Production

by Tomohiro Nishimura, J. Sam Murray, Michael J. Boundy, Muharrem Balci, Holly A. Bowers, Kirsty F. Smith, D. Tim Harwood and Lesley L. Rhodes

Toxins 2021, 13(9), 637; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13090637 - 10 Sep 2021

Cited by 10 | Viewed by 4640

Abstract

Domoic acid (DA) is produced by almost half of the species belonging to the diatom genus Pseudo-nitzschia and causes amnesic shellfish poisoning (ASP). It is, therefore, important to investigate the diversity and toxin production of Pseudo-nitzschia species for ASP risk assessments. Between 2018 and 2020, seawater samples were collected from various sites around Aotearoa New Zealand, and 130 clonal isolates of Pseudo-nitzschia were established. Molecular phylogenetic analysis of partial large subunit ribosomal DNA and/or internal transcribed spacer regions revealed that the isolates were divided into 14 species (Pseudo-nitzschia americana, Pseudo-nitzschia arenysensis, Pseudo-nitzschia australis, Pseudo-nitzschia calliantha, Pseudo-nitzschia cuspidata, Pseudo-nitzschia delicatissima, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia galaxiae, Pseudo-nitzschia hasleana, Pseudo-nitzschia multiseries, Pseudo-nitzschia multistriata, Pseudo-nitzschia plurisecta, Pseudo-nitzschia pungens, and Pseudo-nitzschia cf. subpacifica). The P. delicatissima and P. hasleana strains were further divided into two clades/subclades (I and II). Liquid chromatography-tandem mass spectrometry was used to assess the production of DA and DA isomers by 73 representative strains. The analyses revealed that two (P. australis and P. multiseries) of the 14 species produced DA as a primary analogue, along with several DA isomers. This study is the first geographical distribution record of P. arenysensis, P.cuspidata, P. galaxiae, and P. hasleana in New Zealand coastal waters. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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17 pages, 986 KiB

Open AccessEditor’s ChoiceArticle

Sub-Acute Feeding Study of Saxitoxin to Mice Confirms the Effectiveness of Current Regulatory Limits for Paralytic Shellfish Toxins

by Sarah C. Finch, Nicola G. Webb, Michael J. Boundy, D. Tim Harwood, John S. Munday, Jan M. Sprosen, Vanessa M. Cave, Ric B. Broadhurst and Jeane Nicolas

Toxins 2021, 13(9), 627; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13090627 - 07 Sep 2021

Cited by 6 | Viewed by 2634

Abstract

Regulatory limits for shellfish toxins are required to protect human health. Often these limits are set using only acute toxicity data, which is significant, as in some communities, shellfish makes up a large proportion of their daily diet and can be contaminated with paralytic shellfish toxins (PSTs) for several months. In the current study, feeding protocols were developed to mimic human feeding behaviour and diets containing three dose rates of saxitoxin dihydrochloride (STX.2HCl) were fed to mice for 21 days. This yielded STX.2HCl dose rates of up to 730 µg/kg bw/day with no effects on food consumption, growth, blood pressure, heart rate, motor coordination, grip strength, blood chemistry, haematology, organ weights or tissue histology. Using the 100-fold safety factor to extrapolate from animals to humans yields a dose rate of 7.3 µg/kg bw/day, which is well above the current acute reference dose (ARfD) of 0.5 µg STX.2HCl eq/kg bw proposed by the European Food Safety Authority. Furthermore, to reach the dose rate of 7.3 µg/kg bw, a 60 or 70 kg human would have to consume 540 or 630 g of shellfish contaminated with PSTs at the current regulatory limit (800 µg/kg shellfish flesh), respectively. The current regulatory limit for PSTs therefore seems appropriate. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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23 pages, 2967 KiB

Open AccessArticle

A Comparative Analysis of Methods (LC-MS/MS, LC-MS and Rapid Test Kits) for the Determination of Diarrhetic Shellfish Toxins in Oysters, Mussels and Pipis

by Penelope A. Ajani, Chowdhury Sarowar, Alison Turnbull, Hazel Farrell, Anthony Zammit, Stuart Helleren, Gustaaf Hallegraeff and Shauna A. Murray

Toxins 2021, 13(8), 563; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13080563 - 11 Aug 2021

Cited by 4 | Viewed by 3540

Abstract

Rapid methods for the detection of biotoxins in shellfish can assist the seafood industry and safeguard public health. Diarrhetic Shellfish Toxins (DSTs) are produced by species of the dinoflagellate genus Dinophysis, yet the comparative efficacy of their detection methods has not been systematically determined. Here, we examined DSTs in spiked and naturally contaminated shellfish–Sydney Rock Oysters (Saccostrea glomerata), Pacific Oysters (Magallana gigas/Crassostrea gigas), Blue Mussels (Mytilus galloprovincialis) and Pipis (Plebidonax deltoides/Donax deltoides), using LC-MS/MS and LC-MS in 4 laboratories, and 5 rapid test kits (quantitative Enzyme-Linked Immunosorbent Assay (ELISA) and Protein Phosphatase Inhibition Assay (PP2A), and qualitative Lateral Flow Assay (LFA)). We found all toxins in all species could be recovered by all laboratories using LC-MS/MS (Liquid Chromatography—tandem Mass Spectrometry) and LC-MS (Liquid Chromatography—Mass Spectrometry); however, DST recovery at low and mid-level concentrations (<0.1 mg/kg) was variable (0–150%), while recovery at high-level concentrations (>0.86 mg/kg) was higher (60–262%). While no clear differences were observed between shellfish, all kits delivered an unacceptably high level (25–100%) of falsely compliant results for spiked samples. The LFA and the PP2A kits performed satisfactorily for naturally contaminated pipis (0%, 5% falsely compliant, respectively). There were correlations between spiked DSTs and quantitative methods was highest for LC-MS (r² = 0.86) and the PP2A kit (r² = 0.72). Overall, our results do not support the use of any DST rapid test kit as a stand-alone quality assurance measure at this time. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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13 pages, 2149 KiB

Open AccessArticle

First Report of Domoic Acid Production from Pseudo-nitzschia multistriata in Paracas Bay (Peru)

by Cecil Tenorio, Gonzalo Álvarez, Sonia Quijano-Scheggia, Melissa Perez-Alania, Natalia Arakaki, Michael Araya, Francisco Álvarez, Juan Blanco and Eduardo Uribe

Toxins 2021, 13(6), 408; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13060408 - 09 Jun 2021

Cited by 6 | Viewed by 3634

Abstract

The Peruvian sea is one of the most productive ecosystems in the world. Phytoplankton production provides food for fish, mammals, mollusks and birds. This trophic network is affected by the presence of toxic phytoplankton species. In July 2017, samples of phytoplankton were obtained from Paracas Bay, an important zone for scallop (Argopecten purpuratus) aquaculture in Peru. Morphological analysis revealed the presence of the genus Pseudo-nitzschia, which was isolated and cultivated in laboratory conditions. Subsequently, the monoclonal cultures were observed by scanning electron microscopy (SEM), and identified as P. multistriata, based on both the morphological characteristics, and internal transcribed spacers region (ITS2) sequence phylogenetic analysis. Toxin analysis using liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) revealed the presence of domoic acid (DA) with an estimated amount of 0.004 to 0.010 pg cell⁻¹. This is the first report of DA from the coastal waters of Peru and its detection in P. multistriata indicates that it is a potential risk. Based on our results, routine monitoring of this genus should be considered in order to ensure public health. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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15 pages, 2298 KiB

Open AccessArticle

Acute Toxicity of Gambierone and Quantitative Analysis of Gambierones Produced by Cohabitating Benthic Dinoflagellates

by J. Sam Murray, Sarah C. Finch, Jonathan Puddick, Lesley L. Rhodes, D. Tim Harwood, Roel van Ginkel and Michèle R. Prinsep

Toxins 2021, 13(5), 333; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13050333 - 05 May 2021

Cited by 17 | Viewed by 2770

Abstract

Understanding the toxicity and production rates of the various secondary metabolites produced by Gambierdiscus and cohabitating benthic dinoflagellates is essential to unravelling the complexities associated with ciguatera poisoning. In the present study, a sulphated cyclic polyether, gambierone, was purified from Gambierdiscus cheloniae CAWD232 and its acute toxicity was determined using intraperitoneal injection into mice. It was shown to be of low toxicity with an LD₅₀ of 2.4 mg/kg, 9600 times less toxic than the commonly implicated Pacific ciguatoxin-1B, indicating it is unlikely to play a role in ciguatera poisoning. In addition, the production of gambierone and 44-methylgambierone was assessed from 20 isolates of ten Gambierdiscus, two Coolia and two Fukuyoa species using quantitative liquid chromatography–tandem mass spectrometry. Gambierone was produced by seven Gambierdiscus species, ranging from 1 to 87 pg/cell, and one species from each of the genera Coolia and Fukuyoa, ranging from 2 to 17 pg/cell. The production of 44-methylgambierone ranged from 5 to 270 pg/cell and was ubiquitous to all Gambierdiscus species tested, as well as both species of Coolia and Fukuyoa. The relative production ratio of these two secondary metabolites revealed that only two species produced more gambierone, G. carpenteri CAWD237 and G. cheloniae CAWD232. This represents the first report of gambierone acute toxicity and production by these cohabitating benthic dinoflagellate species. While these results demonstrate that gambierones are unlikely to pose a risk to human health, further research is required to understand if they bioaccumulate in the marine food web. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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15 pages, 2232 KiB

Open AccessArticle

Shellfish Toxin Uptake and Depuration in Multiple Atlantic Canadian Molluscan Species: Application to Selection of Sentinel Species in Monitoring Programs

by Wade A. Rourke, Andrew Justason, Jennifer L. Martin and Cory J. Murphy

Toxins 2021, 13(2), 168; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13020168 - 22 Feb 2021

Cited by 7 | Viewed by 2622

Abstract

Shellfish toxin monitoring programs often use mussels as the sentinel species to represent risk in other bivalve shellfish species. Studies have examined accumulation and depuration rates in various species, but little information is available to compare multiple species from the same harvest area. A 2-year research project was performed to validate the use of mussels as the sentinel species to represent other relevant eastern Canadian shellfish species (clams, scallops, and oysters). Samples were collected simultaneously from Deadmans Harbour, NB, and were tested for paralytic shellfish toxins (PSTs) and amnesic shellfish toxin (AST). Phytoplankton was also monitored at this site. Scallops accumulated PSTs and AST sooner, at higher concentrations, and retained toxins longer than mussels. Data from monitoring program samples in Mahone Bay, NS, are presented as a real-world validation of findings. Simultaneous sampling of mussels and scallops showed significant differences between shellfish toxin results in these species. These data suggest more consideration should be given to situations where multiple species are present, especially scallops. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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15 pages, 20695 KiB

Open AccessArticle

Lobster Supply Chains Are Not at Risk from Paralytic Shellfish Toxin Accumulation during Wet Storage

by Alison Turnbull, Andreas Seger, Jessica Jolley, Gustaaf Hallegraeff, Graeme Knowles and Quinn Fitzgibbon

Toxins 2021, 13(2), 129; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13020129 - 09 Feb 2021

Cited by 1 | Viewed by 2483

Abstract

Lobster species can accumulate paralytic shellfish toxins (PST) in their hepatopancreas following the consumption of toxic prey. The Southern Rock Lobster (SRL), Jasus edwardsii, industry in Tasmania, Australia, and New Zealand, collectively valued at AUD 365 M, actively manages PST risk based on toxin monitoring of lobsters in coastal waters. The SRL supply chain predominantly provides live lobsters, which includes wet holding in fishing vessels, sea-cages, or processing facilities for periods of up to several months. Survival, quality, and safety of this largely exported high-value product is a major consideration for the industry. In a controlled experiment, SRL were exposed to highly toxic cultures of Alexandrium catenella at field relevant concentrations (2 × 10⁵ cells L⁻¹) in an experimental aquaculture facility over a period of 21 days. While significant PST accumulation in the lobster hepatopancreas has been reported in parallel experiments feeding lobsters with toxic mussels, no PST toxin accumulated in this experiment from exposure to toxic algal cells, and no negative impact on lobster health was observed as assessed via a wide range of behavioural, immunological, and physiological measures. We conclude that there is no risk of PST accumulation, nor risk to survival or quality at the point of consumption through exposure to toxic algal cells. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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9 pages, 1557 KiB

Open AccessArticle

Brevisulcenals-A1 and A2, Sulfate Esters of Brevisulcenals, Isolated from the Red Tide Dinoflagellate Karenia brevisulcata

by Masayuki Satake, Raku Irie, Patrick T. Holland, D Tim Harwood, Feng Shi, Yoshiyuki Itoh, Fumiaki Hayashi and Huiping Zhang

Toxins 2021, 13(2), 82; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13020082 - 22 Jan 2021

Cited by 3 | Viewed by 1786

Abstract

Two different types of polycyclic ether toxins, namely brevisulcenals (KBTs) and brevisulcatic acids (BSXs), produced by the red tide dinoflagellate Karenia brevisulcata, were the cause of a toxic incident that occurred in New Zealand in 1998. Four major components, KBT-F, -G, -H, and -I, shown to be cytotoxic and lethal in mice, were isolated from cultured K. brevisulcata cells, and their structures were elucidated by spectroscopic analyses. New analogues, brevisulcenal-A1 (KBT-A1) and brevisulcenal-A2 (KBT-A2), toxins of higher polarity than that of known KBTs, were isolated from neutral lipophilic extracts of bulk dinoflagellate culture extracts. The structures of KBT-A1 and KBT-A2 were elucidated as sulfated analogues of KBT-F and KBT-G, respectively, by NMR and matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI TOF/TOF), and by comparison with the spectra of KBT-F and KBT-G. The cytotoxicities of the sulfate analogues were lower than those of KBT-F and KBT-G. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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14 pages, 1367 KiB

Open AccessArticle

Risk Assessment of Pectenotoxins in New Zealand Bivalve Molluscan Shellfish, 2009–2019

by Michael J. Boundy, D Tim Harwood, Andreas Kiermeier, Cath McLeod, Jeane Nicolas and Sarah Finch

Toxins 2020, 12(12), 776; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins12120776 - 06 Dec 2020

Cited by 9 | Viewed by 6939

Abstract

Pectenotoxins (PTXs) are produced by Dinophysis spp., along with okadaic acid, dinophysistoxin 1, and dinophysistoxin 2. The okadaic acid group toxins cause diarrhetic shellfish poisoning (DSP), so are therefore regulated. New Zealand currently includes pectenotoxins within the DSP regulations. To determine the impact of this decision, shellfish biotoxin data collected between 2009 and 2019 were examined. They showed that 85 samples exceeded the DSP regulatory limit (0.45%) and that excluding pectenotoxins would have reduced this by 10% to 76 samples. The incidence (1.3%) and maximum concentrations of pectenotoxins (0.079 mg/kg) were also found to be low, well below the current European Food Safety Authority (EFSA) safe limit of 0.12 mg/kg. Inclusion within the DSP regulations is scientifically flawed, as pectenotoxins and okadaic acid have a different mechanism of action, meaning that their toxicities are not additive, which is the fundamental principle of grouping toxins. Furthermore, evaluation of the available toxicity data suggests that pectenotoxins have very low oral toxicity, with recent studies showing no oral toxicity in mice dosed with the PTX analogue PTX2 at 5000 µg/kg. No known human illnesses have been reported due to exposure to pectenotoxins in shellfish, a fact which combined with the toxicity data indicates that they pose negligible risk to humans. Regulatory policies should be commensurate with the level of risk, thus deregulation of PTXs ought to be considered, a stance already adopted by some countries. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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19 pages, 11003 KiB

Open AccessArticle

Dihydrodinophysistoxin-1 Produced by Dinophysis norvegica in the Gulf of Maine, USA and Its Accumulation in Shellfish

by Jonathan R. Deeds, Whitney L. Stutts, Mary Dawn Celiz, Jill MacLeod, Amy E. Hamilton, Bryant J. Lewis, David W. Miller, Kohl Kanwit, Juliette L. Smith, David M. Kulis, Pearse McCarron, Carlton D. Rauschenberg, Craig A. Burnell, Stephen D. Archer, Jerry Borchert and Shelley K. Lankford

Toxins 2020, 12(9), 533; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins12090533 - 20 Aug 2020

Cited by 11 | Viewed by 3846

Abstract

Dihydrodinophysistoxin-1 (dihydro-DTX1, (M-H)⁻m/z 819.5), described previously from a marine sponge but never identified as to its biological source or described in shellfish, was detected in multiple species of commercial shellfish collected from the central coast of the Gulf of Maine, USA in 2016 and in 2018 during blooms of the dinoflagellate Dinophysis norvegica. Toxin screening by protein phosphatase inhibition (PPIA) first detected the presence of diarrhetic shellfish poisoning-like bioactivity; however, confirmatory analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) failed to detect okadaic acid (OA, (M-H)⁻m/z 803.5), dinophysistoxin-1 (DTX1, (M-H)⁻m/z 817.5), or dinophysistoxin-2 (DTX2, (M-H)⁻m/z 803.5) in samples collected during the bloom. Bioactivity-guided fractionation followed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) tentatively identified dihydro-DTX1 in the PPIA active fraction. LC-MS/MS measurements showed an absence of OA, DTX1, and DTX2, but confirmed the presence of dihydro-DTX1 in shellfish during blooms of D. norvegica in both years, with results correlating well with PPIA testing. Two laboratory cultures of D. norvegica isolated from the 2018 bloom were found to produce dihydro-DTX1 as the sole DSP toxin, confirming the source of this compound in shellfish. Estimated concentrations of dihydro-DTX1 were >0.16 ppm in multiple shellfish species (max. 1.1 ppm) during the blooms in 2016 and 2018. Assuming an equivalent potency and molar response to DTX1, the authority initiated precautionary shellfish harvesting closures in both years. To date, no illnesses have been associated with the presence of dihydro-DTX1 in shellfish in the Gulf of Maine region and studies are underway to determine the potency of this new toxin relative to the currently regulated DSP toxins in order to develop appropriate management guidance. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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Review

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57 pages, 5433 KiB

Open AccessReview

Critical Review and Conceptual and Quantitative Models for the Transfer and Depuration of Ciguatoxins in Fishes

by Michael J. Holmes, Bill Venables and Richard J. Lewis

Toxins 2021, 13(8), 515; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13080515 - 23 Jul 2021

Cited by 18 | Viewed by 3918

Abstract

We review and develop conceptual models for the bio-transfer of ciguatoxins in food chains for Platypus Bay and the Great Barrier Reef on the east coast of Australia. Platypus Bay is unique in repeatedly producing ciguateric fishes in Australia, with ciguatoxins produced by benthic dinoflagellates (Gambierdiscus spp.) growing epiphytically on free-living, benthic macroalgae. The Gambierdiscus are consumed by invertebrates living within the macroalgae, which are preyed upon by small carnivorous fishes, which are then preyed upon by Spanish mackerel (Scomberomorus commerson). We hypothesise that Gambierdiscus and/or Fukuyoa species growing on turf algae are the main source of ciguatoxins entering marine food chains to cause ciguatera on the Great Barrier Reef. The abundance of surgeonfish that feed on turf algae may act as a feedback mechanism controlling the flow of ciguatoxins through this marine food chain. If this hypothesis is broadly applicable, then a reduction in herbivory from overharvesting of herbivores could lead to increases in ciguatera by concentrating ciguatoxins through the remaining, smaller population of herbivores. Modelling the dilution of ciguatoxins by somatic growth in Spanish mackerel and coral trout (Plectropomus leopardus) revealed that growth could not significantly reduce the toxicity of fish flesh, except in young fast-growing fishes or legal-sized fishes contaminated with low levels of ciguatoxins. If Spanish mackerel along the east coast of Australia can depurate ciguatoxins, it is most likely with a half-life of ≤1-year. Our review and conceptual models can aid management and research of ciguatera in Australia, and globally. Full article

(This article belongs to the Special Issue Marine Toxins from Harmful Algae and Seafood Safety)

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