MOLECULAR STUDY OF THE TOXIC ALGAE DINOPHYSIS SPP. FROM THE FRENCH COAST

Dinoflagellates of the genus Dinophysis are agents of Diarrhetic Shellfish Poisoning (DSP). They occur along the French coast and affect shellfish exploitation during most of the year (during spring, summer and autumn). Because this species is difficult to cultivate, very little is known about this organism. The first problem is the species‐delineation within this genus which is sometimes unclear based upon the solely on morphological features, in particular for the complex D. acuminata (D. cf. acuminata,, D. cf. norvegica, D. cf.sacculus, and D. skagii) or the complex D. sacculus (D. sacculus and D. pavillardii). The second problem is its detection in natural samples. French Dinophysis blooms have been reported to be toxic under 100 cells L^?1, a concentration which corresponds to less than 1 cell 10‐mL^?1, as determined by the Utermöhl method of enumeration. Molecular tools may help to resolve these two kind of problems. During one year (spring 1999 to spring 2000), more than 100 fixed samples containing Dinophysis spp. cells were collected along the French coast by the French monitoring network (or REPHY; http://www. ifremer.fr). The genetic diversity of Dinophysis spp. was studied by sequencing and analysis of ribosomal DNA genes. We found that sequences were hightly conserved between species or within the D. acuminata or D. sacculus complex. Two oligonucleotide probes, specific to these complex groups, were designed. Their specificity and sensitivity are actually tested on natural samples by a PCR‐based assay. Furthur investigation will include the development of standard molecular diagnostics due to their rapid and sensitive detection in natural samples.     

Occurrence ofDinophysis spp. and toxic shellfish in the Northern Adriatic

The dynamics of the toxicity of the musselMytilus galloprovincialis was compared between two different shellfish farms, 5 km apart, but using the same cultivation technique. The main differences concerned the freshwater influx and the open aspect to the Gulf of Trieste. It is suggested that a deep closed bay and abundant fresh water inflow are the two main conditions for the low toxicity levels in mussels and for shorter periods of danger. A detailed study of the phytoplankton samples revealed the presence of eight species ofDinophysis in the area of both shellfish farms. During the period of the DSP outbreak in Slovenia (autumn and winter 1989).D. fortii andD. acuminata were the most frequentDinophysis species. There was a high positive correlation between the onset of mussel toxicity and the appearance ofDinophysis spp.     

Phytoplankton composition of the Kandalaksha Gulf, Russian White Sea: Dinophysis and lipophilic toxins in the blue mussel (Mytilus edulis)

Dinophysis acuminata and D. norvegica were observed in plankton net samples during the summer of 2002 from the Kandalaksha Gulf in the White Sea (North European Russia). Prorocentrum lima was found as an epiphyte on subtidal macroalgae in August, but not observed in plankton net samples. Protein phosphatase 2A (PP2A) inhibition measured 127.8 ng OA-equivalent/g of mussel (Mytilus edulis) hepatopancreas from samples collected a few days after when Dinophysis was recorded at a density of 1550 cells L⁻¹. Liquid chromatography–mass spectrometry confirmed presence of several classes of lipophilic shellfish toxins associated with Dinophysis spp. in the mussels including okadaic acid, dinophysistoxin-1, pectenotoxins and yessotoxins. No azaspiracid was detected. This represents the first identification of phycotoxicity in the White Sea.     

Occurrence of okadaic acid,a major diarrheic shellfish toxin,in natural populations ofDinophysis spp. from the eastern coast of North America

Okadaic acid, one of the principal toxin components implicated in cases of diarrheic shellfish poisoning (DSP), was identified for the first time in natural phytoplankton assemblages from North American waters. During periods in late summer when significant quantities of okadaic acid were detected in net haul samples in the lower estuary and Gulf of St Lawrence in eastern Canada, the phytoplankton community consistently contained species of the dinoflagellate genusDinophysis Ehrenberg. The presence of okadaic acid was detected by screening dinoflagellate extracts with an enzyme-linked immunological assay (ELISA); positive results were confirmed by reverse-phase high-performance liquid chromatography (HPLC) separation, followed by fluorescence detection. Okadaic acid was only found in phytoplankton samples in which the photosynthetic dinophysoid speciesD. norvegica andD. acuminata were prominent; blooms of the related heterotrophic speciesD. rotundata exhibited no trace of okadaic acid, nor other suspected DSP components.     

Determination of diarrhetic shellfish toxins in various dinoflagellate species

Sixteen species of unialgal samples of dinoflagellate, either wild or cultured, were tested for production of diarrhetic shellfish toxins such as okadaic acid (OA), dinophysistoxin-1 (DTX1), and pectenotoxins (PTXs). Determination of micro-quantities of the toxins was facilitated by fluorometry and UV HPLC. Seven Dinophysis species were confirmed to produce either OA or DTX1, or both. Toxin content and composition varied regionally and seasonally. Intraspecies variation was also observed among cultured strains of Prorocentrum lima. PTX2 was the only toxin detected among PTX family, and D. fortii was the only species to contain this toxin. author for correspondence     

Contribution to toxicity assessment of <Emphasis Type="BoldItalic">Dinophysis acuminata</Emphasis> (Dinophyceae)

Blooms of Dinophysis in French coastal waters are implicated in most bans on marketing commercial bivalves. However, the relation between Dinophysis cell density and shellfish toxicity is not always consistent. Discrepancies may be due to the simple fact that it is nearly impossible to compare an integral over a few days (shellfish toxin content) and water samples. Furthermore, it seems that cells may have a variable specific toxicity. This work focuses on the variability in cell toxicity taking into account recent findings and using liquid chromatography coupled to mass spectrometry with an ion trap and electrospray interface. Esterified analogues of okadaic acid (DTX-4 and diol-esters) have been identified in cultures of Prorocentrum lima, another okadaic acid producer. These analogues are inactive on some protein phosphatases, contrary to okadaic acid, and seem to protect the cell from harmful effects by the toxin and to be enzymatically hydrolyzed during cell lysis. In order to document specific toxicity and to validate the presence of these analogues, D. acuminata concentrates were subjected to two separate heating and freeze/thaw procedures, respectively inhibiting or promoting hydrolysis. This paper reports on the high variability of D. acuminata specific toxicity and the presence of esters found in half of the samples only.     

Characterization of Dinophysis spp. (Dinophyceae,Dinophysiales) from the mid-Atlantic region of the United States1

Due to the increasing prevalence of Dinophysis spp. and their toxins on every US coast in recent years, the need to identify and monitor for problematic Dinophysis populations has become apparent. Here, we present morphological analyses, using light and scanning electron microscopy, and rDNA sequence analysis, using a ~2-kb sequence of ribosomal ITS1, 5.8S, ITS2, and LSU DNA, of Dinophysis collected in mid-Atlantic estuarine and coastal waters from Virginia to New Jersey to better characterize local populations. In addition, we analyzed for diarrhetic shellfish poisoning (DSP) toxins in water and shellfish samples collected during blooms using liquid-chromatography tandem mass spectrometry and an in vitro protein phosphatase inhibition assay and compared this data to a toxin profile generated from a mid-Atlantic Dinophysis culture. Three distinct morphospecies were documented in mid-Atlantic surface waters: D. acuminata, D. norvegica, and a “small Dinophysis sp.” that was morphologically distinct based on multivariate analysis of morphometric data but was genetically consistent with D. acuminata. While mid-Atlantic D. acuminata could not be distinguished from the other species in the D. acuminata-complex (D. ovum from the Gulf of Mexico and D. sacculus from the western Mediterranean Sea) using the molecular markers chosen, it could be distinguished based on morphometrics. Okadaic acid, dinophysistoxin 1, and pectenotoxin 2 were found in filtered water and shellfish samples during Dinophysis blooms in the mid-Atlantic region, as well as in a locally isolated D. acuminata culture. However, DSP toxins exceeded regulatory guidance concentrations only a few times during the study period and only in noncommercial shellfish samples.     

Food selectivity and grazing impact on toxic Dinophysis spp. by copepods feeding on natural plankton assemblages

Food selectivity and grazing impact by Acartia bifilosa, Temora longicornis and Centropages typicus on Dinophysis spp. plankton assemblages were experimentally investigated in the Baltic Sea. Toxin analyses were carried out on phyto- and zooplankton-dominated size fractions from field-collected samples to assess if toxins produced by Dinophysis spp. would end up in the zooplankton. All copepod species fed actively on toxic Dinophysis spp. (Dinophysis acuta and Dinophysis norvegica). Despite the non-selective feeding behaviour by T. longicornis and C. typicus, selectivity coefficients on D. acuta progressively decreased as food availability increased. Similar response was not observed for A. bifilosa, which displayed an even less selective behaviour. A. bifilosa had no significant negative effect on the net growth of D. norvegica at the lowest food concentration offered, whereas T. longicornis and C. typicus had significant negative effects on the net growth of D. acuta at low concentrations, similar to those observed in situ. Both species could potentially contribute as a substantial loss factor for Dinophysis spp. provided they are abundant at the onset of the blooms. The estimated grazing impact by the copepod populations was only considerable when C. typicus abundance was high and D. acuta population in sharp decline. Our results suggest that when high abundance of grazers and poor growth condition of prey populations prevail, grazing impact by copepods can contribute considerably to prevent Dinophysis spp. populations to grow or to cause the populations to decline. Okadaic acid was detected in the zooplankton size fraction at one occasion, but the concentration was far lower than the one expected from the ingested toxins. Thus, even if copepods may act as vectors of DSP-toxins to higher trophic levels, the amount of these toxins transported in the food web by copepods seems limited.     

DSP toxin production de novo in cultures of Dinophysis acuminata (Dinophyceae) from North America

For decades, many aspects of Dinophysis biology have remained intractable due to our inability to maintain these organisms in laboratory cultures. Recent breakthroughs in culture methods have opened the door for detailed investigations of these important algae. Here, for the first time, we demonstrate toxin production in cultures of North American Dinophysis acuminata, isolated from Woods Hole, MA. These findings show that, despite the rarity of Dinophysis-related DSP events in North America, D. acuminata from this area has the ability to produce DSP toxins just as it does in other parts of the world where this species is a major cause of DSP toxicity. In our cultures, D. acuminata cells were observed feeding on Myrionecta rubra using a peduncle. Culture extracts were analyzed using LC–MS/MS, providing unequivocal evidence for the toxin DTX1 in the Dinophysis cultures. In addition, a significant amount of an okadaic acid diol ester, OA-D8, was detected. These results suggest that this Dinophysis isolate stores much of its OA as a diol ester. Also, toxin PTX-2 and a hydroxylated PTX-2 with identical fragmentation mass spectrum to that of PTX-11, but with a different retention time, were detected in this D. acuminata culture. This demonstration of toxin production in cultured North American Dinophysis sets the stage for more detailed studies investigating the causes of geographic differences in toxicity. It is now clear that North American Dinophysis have the ability to produce DSP toxins even though they only rarely cause toxic DSP events in nature. This may reflect environmental conditions that might induce or repress toxin production, genetic differences that cause modifications in toxin gene expression, or physiological and biochemical differences in prey species.     

FIRST HARMFUL DINOPHYSIS (DINOPHYCEAE,DINOPHYSIALES) BLOOM IN THE U.S. IS REVEALED BY AUTOMATED IMAGING FLOW CYTOMETRY1

Imaging FlowCytobot (IFCB) combines video and flow cytometric technology to capture images of nano‐ and microplankton (～10 to >100 μm) and to measure the chlorophyll fluorescence associated with each image. The images are of sufficient resolution to identify many organisms to genus or even species level. IFCB has provided >200 million images since its installation at the entrance to the Mission‐Aransas estuary (Port Aransas, TX, USA) in September 2007. In early February 2008, Dinophysis cells (1–5 · mL^?1) were detected by manual inspection of images; by late February, abundance estimates exceeded 200 cells · mL^?1. Manual microscopy of water samples from the site confirmed that D. cf. ovum F. Schütt was the dominant species, with cell concentrations similar to those calculated from IFCB data, and toxin analyses showed that okadaic acid was present, which led to closing of shellfish harvesting. Analysis of the time series using automated image classification (extraction of image features and supervised machine learning algorithms) revealed a dynamic phytoplankton community composition. Before the Dinophysis bloom, Myrionecta rubra (a prey item of Dinophysis) was observed, and another potentially toxic dinoflagellate, Prorocentrum, was observed after the bloom. Dinophysis cell‐division rates, as estimated from the frequency of dividing cells, were the highest at the beginning of the bloom. Considered on a daily basis, cell concentration increased roughly exponentially up to the bloom peak, but closer inspection revealed that the increases generally occurred when the direction of water flow was into the estuary, suggesting the source of the bloom was offshore.     

Phytoplankton detection and DSP toxicity: methodological considerations

Two different phytoplankton sampling methods (bottle and net sampling) were used to evaluate the concentration of toxicDinophysis species in seawater and their correlation to mussel toxicity, assessed by mouse bioassay.Dinophysis concentration in net samples revealed the higher correlation to mussel toxicity (r=0.75,p<0.01). Net sampling therefore seems more suitable for the detection of low abundance species likeDinophysis characterised by vertical aggregations at different depths in the water column.     

First evidence of cell deformation occurrence during a Dinophysis bloom along the shores of the Gulf of Tunis (SW Mediterranean Sea)

Never before observed or cited in Dinophysis studies, deformations in Dinophysis acuminata and Dinophysis sacculus are reported throughout their cellular division phases (cytokinesis, and sulcal list regeneration) in 5 in situ cell cycle studies in the Punic harbors of Carthage (northern Tunisia). Two types of deformation were observed: invaginations in the ventral and dorsal margin and protuberances at the base of the left sulcal list. No virus or bacteria were detected with Syber green stain. In situ division rates (μ) varied among seasons and stations for the same species. D. acuminata exhibited moderate (0.22 day⁻¹) to high (0.68 day⁻¹) μ rates which were however very low (0.02–0.17 day⁻¹) for D. sacculus in autumn and moderate (0.21–0.35 day⁻¹) in late spring. In 2009 the seasonal distribution of Dinophysis indicates maximum Dinophysis cf. ovum abundance in March and a high number of D. acuminata in early June, while in 2010 maximum abundance of the same species was found in mid-June.Molecular and genetic studies and staining with specific fluorescent strains should be addressed to hopefully explain these Dinophysis cell deformations during their in situ division.     

Seasonal distribution of species of the toxic dinoflagellate genus Dinophysis in Maizuru Bay (Japan), with comments on their autofluorescence and attachment of picophytoplankton

The seasonal distribution of the dinoflagellate genus, Dinophysis, in Maizuru Bay, Japan, was investigated from May 1997 to December 1999. Seven species of Dinophysis were detected, including the toxic species of Dinophysis acuminata and D. fortii. The most dominant species wasD. acuminata, detected year-around and more abundantly during periods when water temperatures were between 15 and 18 °C. No relationship was found between cell abundance of Dinophysis spp. and concentrations of dissolved inorganic nutrients. Phycoerythrin containing nano- and picophytoplankton (cryptophytes and cyanobacteria), suspected to be prey of mixotrophic Dinophysis, were enumerated simultaneously. A clear relationship was not found among the cell abundances of Dinophysis spp. and nano- and picophytoplankton. Autofluorescence of Dinophysis spp. (mainly D. acuminata and D. fortii) under blue-light excitation was usually of a yellow-orange color. Occasionally, Dinophysis spp. had red autofluorescencing and yellow-orange autofluorescencing particles. The proportion of cells possessing red autofluorescence tended to be higher in the warm season. Numerous coccoid cells of picophytoplankton (ca. 1–2 μm in diameter) were found attached to the cell surface of D. acuminata, D. fortii, etc. and food vacuole-like structures also observed. These observations suggest there is a close relationship between mixotrophic Dinophysis spp. and certain picophytoplankton. Based on our observations, the possibility that the picophytoplankton found to be attached onto Dinophysis cell surfaces are a food source for Dinophysis, and a source of DSP toxins, is discussed.     

Okadaic acid accumulation in macrofilter feeders subjected to natural blooms of Dinophysis acuminata

Thermaikos Gulf is a eutrophic area located in the Northwestern part of the Aegean Sea in the Eastern Mediterranean. Interspecific differences among various filter feeders in their ability to accumulate okadaic acid, were observed during natural blooms of Dinophysis acuminata in the gulf. Okadaic acid analyses by high performance liquid chromatography (HPLC) were performed on benthic specimens and D. acuminata cell densities and cell toxin content were estimated in water samples. Seven filter feeding species were collected in the gulf during two DSP outbreaks in May 2003 and March 2004. The various species showed a different potential to accumulate okadaic acid in their tissues. The highest concentrations were found in the mussel populations (Mytilus galloprovincialis and Modiolus barbatus), while among the non-bivalve filter feeders, ascidians were the main accumulators of okadaic acid. The rest of shellfish populations (Flexopecten proteus, Chlamys varia and Venus verrucosa) were found to contain toxins only during 2004, when D. acuminata densities were found above 10000 cells l⁻¹. M. galloprovincialis was proved to be the most appropriate indicator for a safe warning of okadaic acid contamination in Thermaikos Gulf.     

Are the mitochondrial cox1 and cob genes suitable markers for species of Dinophysis Ehrenberg?

The identification of Dinophysis species with similar morphology but different toxic (Diarrhetic Shellfish Poisoning, DSP) potential is a crucial task in harmful algae monitoring programmes. The taxonomic assignment of Dinophysis species using molecular markers is a difficult task due to extremely low interspecific variability within their nuclear ribosomal genes and intergenic regions. Mitochondrial cox1 gene has been proposed as a better specific marker for Dinophysis species based on its higher resolution for two morphologically related species (Dinophysis acuminata and Dinophysis ovum) of the “Dinophysis acuminata complex”. In this study, the potential of two mitochondrial genes (mt cox1 and cob) to discriminate among six Dinophysis species (field isolates and cultures) associated with DSP events was explored. Neither mt cox1 nor cob genes provided enough resolution for all species of Dinophysis. The cob gene showed very poor resolution and grouped all Dinophysis spp. in a common clade. In contrast, the cox1 phylogeny distinguished 5 clades in the Dinophysiales – the “acuminata complex”, the “caudata group”, “acuta + norvegica” and Phalacromaspp. However, within the “D. acuminata complex” mtcox1 is so far the unique marker that differentiates D. acuminata from other species: isolates of D. ovum and Dinophysis sacculus had almost identical sequences (only four mismatches), but they were well separated from D. acuminata. D. acuminata and Dinophysis skagii (considered a life cycle stage of the former) showed identical cox1 sequences. Probes towards this gene can be useful in Mediterranean and Western Iberia sites where the co-occurrence of close morphotypes of D. acuminata and D. sacculus pose a problem for monitoring analyses. This is the first report on cultures of D. sacculus and its phylogenetic relation with other species of the D. acuminata complex.     

Epiphytic abundance and toxicity of Prorocentrum lima populations in the Fleet Lagoon, UK

Planktonic Dinophysis spp. and epiphytic Prorocentrum lima (Ehrenberg) Dodge are known dinoflagellate producers of okadaic acid (OA) and dinophysistoxins (DTX), causative phycotoxins of diarrhetic shellfish poisoning (DSP). Underestimation of toxic dinoflagellates associated with a toxic event may be due to the lack of sampling of species with epiphytic and epibenthic strategies, such as P. lima. As Dinophysis spp. is not found in the Fleet Lagoon, Dorset, but previous DSP events have closed the Crassostrea gigas oyster farm, P. lima is the most likely causative organism. A field assay for separating microalgal epiphytes and concentrating wild cells on to filters was successfully applied to sub-samples of a variety of macroalgae and macrophytes (seagrass) collected from the Fleet during summer 2002. P. lima was present in increasing cell densities on most substratum species, over the sampling period, from 10² to 10³ cells g⁻¹ fresh weight (FW) plant biomass. LC–MS analysis detected OA and DTX-1 in extracts of wild P. lima cells, in ratios characteristic of P. lima strains previously isolated from the Fleet. No toxins, however, were detected in oyster flesh.     

Large subunit ribosomal RNA gene variation and sequence heterogeneity of Dinophysis (Dinophyceae) species from Scottish coastal waters

The purpose of the study was to investigate the genetic diversity of Dinophysis species from around the Scottish coast, with a view to an improved understanding of the dynamics and identification of this genus in Scottish waters. Single-cell PCR amplification with direct sequencing was performed on a total of 441 Dinophysis cells isolated from both live and Lugol's fixed plankton net samples. Universal eukaryotic primers were used to amplify the large subunit (LSU) ribosomal RNA (rRNA) gene of the Dinophysis isolates, with a frequency of PCR success of 26% for non-fixed and 48% for fixed samples. From this a total of 30 isolates were selected for this study and the D1–D2 region of the LSU-rRNA gene sequenced for phylogenetic analysis. No significant correlation could be made between geographical location and LSU sequence, although some regional sequence heterogeneity was observed within the Dinophysis acuta species. LSU sequence data was used to design Dinophysis genus specific and Dinophysis clade-specific primers primarily to ensure clean sequences from universal D1–D2 amplicons without a requirement for cloning. Three clade-specific primers designed to a region within the D2 hypervariable region of the LSU-rRNA gene allowed discrimination of Dinophysis acuminata/norvegica from Dinophysis tripos/caudata and Dinophysis fortii/acuta. In two isolates, SC359 (D. tripos) and LC58 (D. acuta), nested PCR products were observed with both the expected clade-specific primer, and Dasd-R2, the D. acuminata/norvegica clade-specific primer. Cloning and sequence analysis suggested that these amplicons were genuine “D. acuminata-like” sequences and their presence, albeit at a low frequency within different Dinophysis species, indicated that individual Dinophysis cells possess heterologous copies of the LSU-rRNA gene that are similar to LSU sequences normally associated with D. acuminata. The nature of the process that generated these hybrid cells, the frequency of such events and their importance is as yet unknown, but may provide a cautionary note for the development of PCR-based species specific detection methods.     

Seasonality of Dinophysis spp. and Prorocentrum lima in Black Sea phytoplankton and associated shellfish toxicity

Plankton surveys, between 2001 and 2005 along the Russian Caucasian Black Sea Coast, revealed Dinophysis rotundata, D. caudata and Prorocentrum lima as the most ubiquitous of the known dinoflagellates associated with diarrhetic shellfish poisoning (DSP). Dinophysis spp. were first observed during the spring phytoplankton succession and persist throughout the late summer phytoplankton peak. The highest total concentration, 3000 cells/L, of D. rotundata and D. caudata was observed in April 2001. Unlike Dinophysis, P. lima was rarely observed in plankton samples but closely followed storm events with maximum cell counts of P. lima occurred in July 2002.The presence of Dinophysis in mussel (Mytilus galloprovincialis) hepatopancreas correlated with concentration with Dinophysis observed in the plankton samples. Conversely, P. lima could be found in most hepatopancreas samples collected during the May to October period. Therefore, planktonic concentration of P. lima does not reflect its availability for and consumption by shellfish.Samples of mussel hepatopancreas, from August 2002, with a corresponding Dinophysis concentration of 250 cells/L and no observable P. lima, were found to contain 0.03 ng OAE/g. This sample analyses by LC-MS/MS displayed okadaic acid (OA) and related congeners (DTX1) along with the pectinotoxins (PTX2 and PTX2sa). Highest observed levels of P. lima-induced DSP-toxicity in hepatopancreas was 0.41 g OA-equivalents/g corresponded to the highest observed planktonic cell counts of P. lima, 300 cell/L in August 2001. Cultures isolated from this sample were found to produce OA, DTX1 and their related diol esters.These data reveal a threat, represented by DSP-toxic species, at Black Sea coasts, and provide grounds for the introduction of phycotoxin control measures in the region.     

A survey of Dinophysis spp. and their potential to cause diarrhetic shellfish poisoning in coastal waters of the United States

Multiple species of the genus Dinophysis produce diarrhetic shellfish toxins (okadaic acid and Dinophysis toxins, OA/DTXs analogs) and/or pectenotoxins (PTXs). Only since 2008 have DSP events (illnesses and/or shellfish harvesting closures) become recognized as a threat to human health in the United States. This study characterized 20 strains representing five species of Dinophysis spp. isolated from three US coastal regions that have experienced DSP events: the Northeast/Mid-Atlantic, the Gulf of Mexico, and the Pacific Northwest. Using a combination of morphometric and DNA-based evidence, seven Northeast/Mid-Atlantic isolates and four Pacific Northwest isolates were classified as D. acuminata, a total of four isolates from two coasts were classified as D. norvegica, two isolates from the Pacific Northwest coast were identified as D. fortii, and three isolates from the Gulf of Mexico were identified as D. ovum and D. caudata. Toxin profiles of D. acuminata and D. norvegica varied by their geographical origin within the United States. Cross-regional comparison of toxin profiles was not possible with the other three species; however, within each region, distinct species-conserved profiles for isolates of D. fortii, D. ovum, and D. caudata were observed. Historical and recent data from various State and Tribal monitoring programs were compiled and compared, including maximum recorded cell abundances of Dinophysis spp., maximum concentrations of OA/DTXs recorded in commercial shellfish species, and durations of harvesting closures, to provide perspective regarding potential for DSP impacts to regional public health and shellfish industry.