scholarly journals Repeated mass strandings of Miocene marine mammals from Atacama Region of Chile point to sudden death at sea

2014 ◽  
Vol 281 (1781) ◽  
pp. 20133316 ◽  
Author(s):  
Nicholas D. Pyenson ◽  
Carolina S. Gutstein ◽  
James F. Parham ◽  
Jacobus P. Le Roux ◽  
Catalina Carreño Chavarría ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Marine Mammals ◽  
Large Scale ◽  
Sperm Whales ◽  
Algal Toxins ◽  
Accumulation Mechanism ◽  
Taphonomic Analysis ◽  
Spatial Focusing

Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities.

scholarly journals An assessment of temporal, spatial and taxonomic trends in harmful algal toxin exposure in stranded marine mammals from the U.S. New England coast

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0243570
Author(s):  
Spencer E. Fire ◽  
Andrea Bogomolni ◽  
Robert A. DiGiovanni ◽  
Greg Early ◽  
Tod A. Leighfield ◽  
...  
Keyword(s):  
New England ◽  
Coastal Waters ◽  
Marine Mammal ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Marine Mammals ◽  
Toxin Detection ◽  
Detection Rates ◽  
Toxin Exposure ◽  
Common Dolphins

Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal waters, corresponding HAB-associated marine mammal mortality events in this region are far less frequent or severe relative to other regions where HABs are common. This long-term survey of the HAB toxins saxitoxin (STX) and domoic acid (DA) demonstrates significant and widespread exposure of these toxins in New England marine mammals, across multiple geographic, temporal and taxonomic groups. Overall, 19% of the 458 animals tested positive for one or more toxins, with 15% and 7% testing positive for STX and DA, respectively. 74% of the 23 different species analyzed demonstrated evidence of toxin exposure. STX was most prevalent in Maine coastal waters, most frequently detected in common dolphins (Delphinus delphis), and most often detected during July and October. DA was most prevalent in animals sampled in offshore locations and in bycaught animals, and most frequently detected in mysticetes, with humpback whales (Megaptera novaeangliae) testing positive at the highest rates. Feces and urine appeared to be the sample matrices most useful for determining the presence of toxins in an exposed animal, with feces samples having the highest concentrations of STX or DA. No relationship was found between the bloom season of toxin-producing phytoplankton and toxin detection rates, however STX was more likely to be present in July and October. No relationship between marine mammal dietary preference and frequency of toxin detection was observed. These findings are an important part of a framework for assessing future marine mammal morbidity and mortality events, as well as monitoring ecosystem health using marine mammals as sentinel organisms for predicting coastal ocean changes.

Shellfish toxicity: human health implications of marine algal toxins

2010 ◽  
Vol 138 (7) ◽  
pp. 927-940 ◽  
Author(s):  
K. J. JAMES ◽  
B. CAREY ◽  
J. O'HALLORAN ◽  
F. N. A. M. van PELT ◽  
Z. ŠKRABÁKOVÁ
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Large Scale ◽  
Global Climate ◽  
Anthropogenic Activities ◽  
Detection Methods ◽  
Algal Toxins ◽  
Marine Transport ◽  
Ecological Changes ◽  
Marine Algal

SUMMARYFive major human toxic syndromes caused by the consumption of shellfish contaminated by algal toxins are presented. The increased risks to humans of shellfish toxicity from the prevalence of harmful algal blooms (HABs) may be a consequence of large-scale ecological changes from anthropogenic activities, especially increased eutrophication, marine transport and aquaculture, and global climate change. Improvements in toxin detection methods and increased toxin surveillance programmes are positive developments in limiting human exposure to shellfish toxins.

scholarly journals Cyanoprokaryotes biodiversity in nine shallow Bulgarian wetlands

2019 ◽  
Vol 2 ◽  
Author(s):  
Blagoy Uzunov ◽  
Maya Stoyneva-Gärtner ◽  
Georg Gärtner ◽  
Mariana Radkova ◽  
Katerina Stefanova
Keyword(s):  
Light Microscopy ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Molecular Methods ◽  
Geographical Pattern ◽  
Algal Toxins ◽  
The Real ◽  
Total Phytoplankton ◽  
Toxigenic Strains ◽  
Conventional Light Microscopy

The results from the investigation of the phytoplankton in nine shallow wetlands, situated in Central and Eastern Bulgaria, conducted in the frame of recent projects related to identifying harmful algal blooms and algal toxins in the country are demonstrated. Therefore, the focus is on the cyanoprokaryotes and their toxigenic species in particular. The species were identified using conventional light microscopy, while for distinguishing the toxigenic species and strains PCR-based molecular methods were applied. Cyanoprokaryotes comprised about 30% of the total phytoplankton biodiversity of the studied wetlands and were unevenly spread among them. The presence and spread of toxigenic strains in the studied wetlands also did not show any strong geographical pattern. Taxonomic problems related with the evaluation of the real cyanoprokaryotic biodiversity and potential alien or invasive character of the morphospecies are discussed.

Environmental pollutants and marine mammal health: The potential impact of hydrocarbons and halogenated hydrocarbons on immune system dysfunction

2020 ◽  
pp. 223-248
Author(s):  
David Busbee ◽  
Ian Tizard ◽  
Jeffrey Sroit ◽  
Davide Ferrirc ◽  
Ellen Orr-reeves
Keyword(s):  
Immune System ◽  
Food Chain ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Large Scale ◽  
Environmental Pollutants ◽  
Halogenated Hydrocarbons ◽  
Mechanisms Of Toxicity ◽  
Terrestrial Mammals ◽  
Immune System Dysfunction

This paper provides a detailed review of the immunotoxicological effects of environmental pollutants on the health of marine mammals, particularly in relation to their impact on the immune system and mechanisms of toxicity. Environmental pollutants are increasingly implicated (both directly and indirectly) with the onset of infectious disease and related mortality incidents in marine mammals,. The release of chemicals into the marine environment and the subsequent bioaccumulation up the food chain may pose a serious threat to marine mammals inhabiting contaminated areas; this has been documented in various studies of pollutant concentrations in tissue samples and large scale mass mortalities. Data correlating pollutant residues with altered reproductive/developmental states, and immune system dysfunction in particular, are reported for terrestrial mammals and suggest a similar association in marine mammals. Immunology is emphasised as a tool for assessing marine mammal health using quantitative and qualitative techniques to establish the effects of chemical pollutants. This has become increasingly important in relation to the subsequent dangers that may be posed to humans through any indirect exposure via the food chain.

scholarly journals Environmental Considerations for the Management of the Bivalve Fisheries of Bahía Magdalena (Mexico), a Coastal Lagoon at the Southern End of the California Current

2021 ◽  
Vol 8 ◽  
Author(s):  
María del Carmen Jiménez-Quiroz ◽  
Francisco Javier Barrón-Barraza ◽  
Rafael Cervantes-Duarte ◽  
René Funes-Rodríguez
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Large Scale ◽  
Environmental Variability ◽  
Southern Oscillation ◽  
Warming Trend ◽  
Regional Warming ◽  
Biological Variables ◽  
The Impact ◽  
Bahia Magdalena

This study presents an overview of bivalve assemblages in Bahia Magdalena (BM, México) and the possible impact of environmental variability on these populations, constantly stressed by fishing. This lagoon is responsible for a high proportion of harvest of regional bivalves. First, we list the bivalve species reported in public biogeographic databases. Based on eight commercially exploited species, we described the composition of the bivalve assemblage and its biological characteristics, the history of fishery, and environmental variability in the marine area adjacent to the lagoon (1970–2019) and the habitat of bivalves (2002–2020). Sources of data were public databases and published literature. The enlisted species (n = 184) belong to six orders, and most are small and infaunal, but the structure of the assemblage is unknown. The fisheries began at different times and focused on the most valuable resources. Almost all harvest of bivalves had wide variations because of intensive fishing and a weak regulation frame. After 2015, the main resources were the Pacific wing-oyster (a new resource since 2017) and the geoduck clam due to the declining abundance of other resources (e.g., pen shells, Pacific calico scallop). There was a warming trend in the region since the 1970's, but the strongest El Niño-Southern Oscillation (ENSO) phases caused the most notable changes before 2013; after that year, a combination of large-scale phenomena increased the temperature significantly. The trend of chlorophyll-a abundance negatively correlated with temperature, but there was an almost constant supply of particulate organic matter in the interior of Bahia Magdalena (BM). After 2015, the quality of lagoon water gradually deteriorated, and in 2017 and 2019, harmful algal blooms developed, but the impact was not fully assessed. The challenges faced by the fishery are multiple (institutional weakness and regional warming); however, permanent monitoring programs of environmental conditions and critical biological variables should be implemented to design scenarios that allow fishery sustainability.

scholarly journals Insights into toxic Prymnesium parvum blooms: the role of sugars and algal viruses

2018 ◽  
Vol 46 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Ben A. Wagstaff ◽  
Edward S. Hems ◽  
Martin Rejzek ◽  
Jennifer Pratscher ◽  
Elliot Brooks ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Large Scale ◽  
Abiotic Factors ◽  
Management Strategies ◽  
Prymnesium Parvum ◽  
Fish Kill ◽  
Economic Implications ◽  
Norfolk Broads

Prymnesium parvum is a toxin-producing microalga that causes harmful algal blooms globally, which often result in large-scale fish kills that have severe ecological and economic implications. Although many toxins have previously been isolated from P. parvum, ambiguity still surrounds the responsible ichthyotoxins in P. parvum blooms and the biotic and abiotic factors that promote bloom toxicity. A major fish kill attributed to P. parvum occurred in Spring 2015 on the Norfolk Broads, a low-lying set of channels and lakes (Broads) found on the East of England. Here, we discuss how water samples taken during this bloom have led to diverse scientific advances ranging from toxin analysis to discovery of a new lytic virus of P. parvum, P. parvum DNA virus (PpDNAV-BW1). Taking recent literature into account, we propose key roles for sialic acids in this type of viral infection. Finally, we discuss recent practical detection and management strategies for controlling these devastating blooms.

Shellfish toxins a public health concern for Canadians

2014 ◽  
Vol 57 (01) ◽  
pp. 16-21 ◽  
Author(s):  
Etran Bouchouar ◽  
Samantha Bruzzese ◽  
Chelsea Pyles ◽  
Kate Stechyshyn
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
The United States ◽  
Health Concern ◽  
Human Consumption ◽  
Shellfish Poisoning ◽  
Algal Toxins ◽  
Heat Stable ◽  
Marine Traffic ◽  
High Concentrations

Harmful algal blooms (HABs) are increasing worldwide as a result of climate change and global marine traffic. HABs contain high concentrations of algal toxins. Toxin contaminated shellfish cannot be detected by taste, sight, or smell; the toxins are heat-stable and therefore are not destroyed by cooking. Human consumption of toxin-contaminated shellfish leads to illness. Treatment of shellfish poisoning is limited to symptom management. The burden of shellfish poisoning in humans is often underestimated, and the effects of chronic exposure are unknown. Currently there are regulatory practices for shellfish monitoring in Canada and the United States. Yet there is poor communication of HAB risks to the public.

scholarly journals Marine mammal skin microbiotas are influenced by host phylogeny

2020 ◽  
Vol 7 (5) ◽  
pp. 192046 ◽  
Author(s):  
Amy Apprill ◽  
Carolyn A. Miller ◽  
Amy M. Van Cise ◽  
Jana M. U'Ren ◽  
Matthew S. Leslie ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
The United States ◽  
Small Subunit ◽  
Sperm Whales ◽  
Animal Group ◽  
Host Phylogeny ◽  
Pilot Whales ◽  
Free Ranging

Skin-associated microorganisms have been shown to play a role in immune function and disease of humans, but are understudied in marine mammals, a diverse animal group that serve as sentinels of ocean health. We examined the microbiota associated with 75 epidermal samples opportunistically collected from nine species within four marine mammal families, including: Balaenopteridae (sei and fin whales), Phocidae (harbour seal), Physeteridae (sperm whales) and Delphinidae (bottlenose dolphins, pantropical spotted dolphins, rough-toothed dolphins, short-finned pilot whales and melon-headed whales). The skin was sampled from free-ranging animals in Hawai‘i (Pacific Ocean) and off the east coast of the United States (Atlantic Ocean), and the composition of the bacterial community was examined using the sequencing of partial small subunit (SSU) ribosomal RNA genes. Skin microbiotas were significantly different among host species and taxonomic families, and microbial community distance was positively correlated with mitochondrial-based host genetic divergence. The oceanic location could play a role in skin microbiota variation, but skin from species sampled in both locations is necessary to determine this influence. These data suggest that a phylosymbiotic relationship may exist between microbiota and their marine mammal hosts, potentially providing specific health and immune-related functions that contribute to the success of these animals in diverse ocean ecosystems.

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