scholarly journals Leopard Seals (Hydrurga leptonyx) in New Zealand Waters Predating on Chondrichthyans

2021 ◽  
Vol 8 ◽  
Author(s):  
Krista van der Linde ◽  
Ingrid N. Visser ◽  
Rick Bout ◽  
Chris Lalas ◽  
Lara Shepherd ◽  
...  
Keyword(s):  
New Zealand ◽  
Dna Sequencing ◽  
High Frequency ◽  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Squalus Acanthias ◽  
Spiny Dogfish ◽  
Frequency Of Occurrence ◽  
Morphological Examination ◽  
Hydrurga Leptonyx

Leopard seals (Hydrurga leptonyx) are top-order predators that prey on a wide variety of species including crustaceans, cephalopods, fishes, birds, and pinnipeds. While multiple diet studies have been conducted worldwide, there are no previous accounts of leopard seals predating on chondrichthyans. As part of a wider study on the diet of leopard seals in New Zealand (NZ) waters, researchers and citizen scientists recorded 39 observations of predation and collected 127 scats (166 total records) between 1942 and 2019. Predation on chondrichthyans was detected in 23.1% (n = 9) of observations of predation and 7.1% (n = 9) of scats (the latter via morphological examination and DNA sequencing). From both observations of predations and scats, three chondrichthyan species or genus were identified; elephantfish (Callorhinchus milii), ghost sharks (Hydrolagus spp.) and spiny dogfish (Squalus acanthias). While this is the first published record of leopard seals feeding on chondrichthyans, the relatively high frequency of occurrence within our NZ records, and that certain individuals appeared to target this type of prey, indicates that these species could constitute a substantial, or important, part of the diet for some leopard seals in this region. As chondrichthyans form an important part of the NZ marine ecosystems, our recognition of an additional top-order predator of these species contributes to understanding the overall health of, and future impacts of predators on, the wider NZ marine ecosystem.

scholarly journals Bounds on Biomass Estimates and Energetic Consequences of Ctenophora in the Northeast U.S. Shelf Ecosystem

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Michael D. Ford ◽  
Jason S. Link
Keyword(s):  
Feeding Strategy ◽  
Marine Ecosystem ◽  
High Energy ◽  
Gelatinous Zooplankton ◽  
Squalus Acanthias ◽  
High Energy Density ◽  
Spiny Dogfish ◽  
Sampling Device ◽  
Large Marine Ecosystem ◽  
Major Increase

Previous descriptions have noted that the stomach samples of spiny dogfish, Squalus acanthias, showed a major increase in the overall occurrence and hence implied abundance of Ctenophora. This apparent and persistent gelatinous zooplankton outbreak is increasingly more common in the world’s oceans. We briefly explore the energetic ramifications of ctenophores in the spiny dogfish diet, inferring that the presence of gelatinous zooplankton represents an ambient feeding strategy. Relative to other prey, ctenophores are not a high energy density prey item. However, given varying assumptions of the amount of ctenophores consumed, they may be an important staple in the diet of spiny dogfish. We also examine the utility of using spiny dogfish as a gelatinous zooplankton sampling device. Using five calculation methodologies, we provide bounds on potential abundance and biomass estimates of ctenophores in the Northeast U.S. shelf ecosystem. We then contextualize these findings relative to the implications for the Northeast U.S. and any large marine ecosystem.

Application of generalized additive models to examine ontogenetic and seasonal distributions of spiny dogfish (Squalus acanthias) in the Northeast (US) shelf large marine ecosystem

2014 ◽  
Vol 71 (6) ◽  
pp. 847-877 ◽  
Author(s):  
Skyler R. Sagarese ◽  
Michael G. Frisk ◽  
Robert M. Cerrato ◽  
Kathy A. Sosebee ◽  
John A. Musick ◽  
...  
Keyword(s):  
Generalized Additive Models ◽  
Marine Ecosystem ◽  
Additive Models ◽  
Squalus Acanthias ◽  
Seasonal Occurrence ◽  
Spiny Dogfish ◽  
Science Center ◽  
Large Marine Ecosystem ◽  
Northeast Us ◽  
The Relationship

Increased commercial importance of spiny dogfish (Squalus acanthias) combined with an often debated, and controversial, ecological impact has warranted an investigation of the relationship among distribution, environment, and prey to better understand the species ecology and inform management. To elucidate mechanisms behind distributional changes, we modeled seasonal occurrence and abundance of neonate, immature, and mature spiny dogfish as functions of abiotic and biotic factors using generalized additive models and Northeast Fisheries Science Center bottom trawl survey data. Significant nonlinear relationships were widespread throughout dogfish stages and seasons. Seasonal occurrence was tightly linked to depth and bottom temperature, with year and Julian day influential for some stages. While these factors also influenced abundance, ecological factors (e.g., squid abundances) significantly contributed to trends for many stages. Potential impacts of climate change were evaluated by forecasting distributions under different temperature scenarios, which revealed higher regional probabilities of occurrence for most stages during a warmer than average year. Our results can be used to better understand the relationship between sampling periods and movement drivers to survey catchability of the population in the Northeast (US) shelf large marine ecosystem.

Accumulation of 210Po by spiny dogfish (Squalus acanthias), elephant fish (Callorhinchus milii) and red gurnard (Chelodonichthys kumu) in New Zealand shelf waters

1997 ◽  
Vol 48 (3) ◽  
pp. 229 ◽  
Author(s):  
Peter Bellamy ◽  
Keith A. Hunter
Keyword(s):  
New Zealand ◽  
Fish Species ◽  
Sea Water ◽  
Radioactive Decay ◽  
Natural Radionuclide ◽  
Absorbed Dose ◽  
Squalus Acanthias ◽  
Spiny Dogfish ◽  
Wet Weight ◽  
Concentration Factors

Concentrations of the natural radionuclide 210Po in the livers of 81 individual specimens of three fish species collected from waters of the Otago continental shelf, New Zealand, have been measured: spiny dogfish (Squalus acanthias), 4·2 ± 1·8 Bq kg-1 wet weight (mean ± standard deviation, n = 48); elephant fish (Callorhinchus milii), 136 ± 39 Bq kg-1 (n = 7); and red gurnard (Chelodonichthys kumu), 38 ± 13 Bq kg-1 (n = 26). Separate measurements showed that only a negligible fraction of the 210Po was supported by decay of the 210Pb parent (210Po/210Pb activity ratios were 15, 134 and 5·9 respectively for the three species), indicating that direct uptake of 210Po into the liver balances losses from excretion and radioactive decay. The radiation dose from 210Po in the livers accounted for between 88% and 99% of the total internal absorbed dose received by the fish species. The activity of 210Po in sea water from the study area was 0·9–2·2 mBq L-1, yielding concentration factors for 210Po in liver tissue in the range 3 × 103 to 100 × 103. No significant monophasic relationships were observed between the 210Po results and the measured concentrations of the elements Cd, Cu, Fe, Mn, Zn and Pb, except that Pb and 210Po were correlated (r = 0·511) in C. kumu.

scholarly journals Parasitic fauna of spiny dogfish Squalus acanthias L. off New Zealand

1984 ◽  
Vol 14 (1-2) ◽  
pp. 157-166 ◽  
Author(s):  
Jadwiga Wierzbicka ◽  
Danuta Łangowska
Keyword(s):  
New Zealand ◽  
Squalus Acanthias ◽  
Spiny Dogfish ◽  
Parasitic Fauna

scholarly journals Spatiotemporal overlap of spiny dogfish (Squalus acanthias) and commercial fisheries in the northeast U.S. shelf large marine ecosystem

2015 ◽  
Vol 113 (2) ◽  
pp. 101-120 ◽  
Author(s):  
Skyler R. Sagarese ◽  
Michael G. Frisk ◽  
Robert M. Cerrato ◽  
Kathy A. Sosebee ◽  
John A. Musick ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Squalus Acanthias ◽  
Commercial Fisheries ◽  
Spiny Dogfish ◽  
Large Marine Ecosystem

Fungus Spaeropsis Malorum peck. One of the currant stalk drying agents

2020 ◽  
Vol 62 ◽  
pp. 172-178
Author(s):  
S. E. Golovin
Keyword(s):  
Causative Agent ◽  
High Frequency ◽  
Frequency Of Occurrence ◽  
Ribes Nigrum ◽  
Black Currant ◽  
Causative Agents ◽  
Pear Trees ◽  
Red Currant

The article highlights the results of research carried out in 2019-2020 to study the reasons for the drying out of the stems of black currant (Ribes nigrum L.), red currant (Ribes rubrum L.) and golden currant (Ribes aureum L.). As a result of research, the fungus Sphaeropsis malorum Peck. in the first in Russia it was revealed from the drying stems of three types of black currants, red currants and golden currants. This  pathogen inhabited currant stems together with fungi from the genus Cytospora spp., causative agents of stem drying. On red currants, it was established that S. malorum was the main causative agent of branch drying, as indicated by the high frequency of occurrence (75.0-83.3 %) of this fungus on the affected stems, compared with species from the genus Cytospora spp. (16.7-33.3 %) and Phomopsis ribesia (25.0 %). Due to the fact that the cultivation of currants in the immediate vicinity of apple and pear trees leads to infection of plants with the fungus S. malorum, it is necessary to avoid planting currants in the vicinity of fruit-bearing seed gardens.

Ultrastructural Changes of Candida albicans Species Induced by the Presence of Sodium Diclofenac

2017 ◽  
Vol 68 (11) ◽  
pp. 2566-2569 ◽  
Author(s):  
Elena Rusu ◽  
Ionela Sarbu ◽  
Magdalena Mitache ◽  
Horatiu Moldovan ◽  
Carmen Ioana Biris ◽  
...  
Keyword(s):  
Candida Albicans ◽  
High Frequency ◽  
Fungal Infections ◽  
Diagnostic Methods ◽  
Ultrastructural Changes ◽  
Frequency Of Occurrence ◽  
Medical Treatments ◽  
Sodium Diclofenac ◽  
Cell Wall Disruption ◽  
Candidiasis Treatment

The high frequency of occurrence of candidiasis as well as high mortality of patients with immunosuppression cause a tendency toward better understanding of Candida albicans species virulence factors and developing sensitive and specific diagnostic methods, and appropriate strategies of candidiasis treatment. In recent decades the incidence of fungal infections has alarming increases because of advanced medical treatments. In this study was analyzed possible ultrastructural changes of the species C. albicans cells following treatment with sodium diclofenac at various concentrations. Following treatment of C. albicans cells with sodium diclofenac 1 mM and 2 mM changes in the plasmalemma can be noticed, changes in the density of cell wall, disruption and necrotic appearance of the cytoplasm.

scholarly journals Historical contingency impacts on community assembly and ecosystem function in chemosynthetic marine ecosystems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dimitri Kalenitchenko ◽  
Erwan Peru ◽  
Pierre E. Galand
Keyword(s):  
Community Assembly ◽  
Sea Water ◽  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Metagenomic Sequencing ◽  
Historical Contingency ◽  
Historical Events ◽  
Species Sorting ◽  
Environmental Selection ◽  
Microbial Community Assembly

AbstractPredicting ecosystem functioning requires an understanding of the mechanisms that drive microbial community assembly. Many studies have explored microbial diversity extensively and environmental factors are thought to be the principal drivers of community composition. Community assembly is, however, also influenced by past conditions that might affect present-day assemblages. Historical events, called legacy effects or historical contingencies, remain poorly studied in the sea and their impact on the functioning of the communities is not known. We tested the influence, if any, of historical contingencies on contemporary community assembly and functions in a marine ecosystem. To do so, we verified if different inoculum communities colonizing the same substrate led to communities with different compositions. We inoculated wood with sea water microbes from different marine environments that differ in ecological and evolutionary history. Using 16S rRNA and metagenomic sequencing, it was demonstrated that historical contingencies change the composition and potential metabolisms of contemporary communities. The effect of historical events was transient, dominated by environmental selection as, over time, species sorting was a more important driver of community assembly. Our study shows not only that historical contingencies affect marine ecosystems but takes the analysis a step further by characterizing this effect as strong but transient.

scholarly journals Trends and Evolution in the Concept of Marine Ecosystem Services: An Overview

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2060
Author(s):  
Elvira Buonocore ◽  
Umberto Grande ◽  
Pier Paolo Franzese ◽  
Giovanni F. Russo
Keyword(s):  
Ecosystem Services ◽  
Alternative Assessment ◽  
Natural Capital ◽  
Marine Ecosystem ◽  
Management Strategies ◽  
Marine Ecosystems ◽  
Global Ocean ◽  
Coastal Protection ◽  
Policy Dialogue ◽  
Marine Ecosystem Services

The biotic and abiotic assets of the marine environment form the “marine natural capital” embedded in the global ocean. Marine natural capital provides the flow of “marine ecosystem services” that are directly used or enjoyed by people providing benefits to human well-being. They include provisioning services (e.g., food), regulation and maintenance services (e.g., carbon sequestration and storage, and coastal protection), and cultural services (e.g., tourism and recreational benefits). In recent decades, human activities have increased the pressures on marine ecosystems, often leading to ecosystem degradation and biodiversity loss and, in turn, affecting their ability to provide benefits to humans. Therefore, effective management strategies are crucial to the conservation of healthy and diverse marine ecosystems and to ensuring their long-term generation of goods and services. Biophysical, economic, and sociocultural assessments of marine ecosystem services are much needed to convey the importance of natural resources to managers and policy makers supporting the development and implementation of policies oriented for the sustainable management of marine resources. In addition, the accounting of marine ecosystem service values can be usefully complemented by their mapping to enable the identification of priority areas and management strategies and to facilitate science–policy dialogue. Given this premise, this study aims to review trends and evolution in the concept of marine ecosystem services. In particular, the global scientific literature on marine ecosystem services is explored by focusing on the following main aspects: the definition and classification of marine ecosystem services; their loss due to anthropogenic pressures, alternative assessment, and mapping approaches; and the inclusion of marine ecosystem services into policy and decision-making processes.

Sign in / Sign up

Export Citation Format

Share Document