Signatures of the collapse and incipient recovery of an overexploited marine ecosystem

The Northwest Atlantic cod stocks collapsed in the early 1990s and have yet to recover, despite the subsequent establishment of a continuing fishing moratorium. Efforts to understand the collapse and lack of recovery have so far focused mainly on the dynamics of commercially harvested species. Here, we use data from a 33-year scientific trawl survey to determine to which degree the signatures of the collapse and recovery of the cod are apparent in the spatial and temporal dynamics of the broader groundfish community. Over this 33-year period, the groundfish community experienced four phases of change: (i) a period of rapid, synchronous biomass collapse in most species, (ii) followed by a regime shift in community composition with a concomitant loss of functional diversity, (iii) followed in turn by periods of slow compositional recovery, and (iv) slow biomass growth. Our results demonstrate how a community-wide perspective can reveal new aspects of the dynamics of collapse and recovery unavailable from the analysis of individual species or a combination of a small number of species. Overall, we found evidence that such community-level signals should be useful for designing more effective management strategies to ensure the persistence of exploited marine ecosystems.

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Spatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: implications for ecosystem-based fisheries management

Marine Ecology Progress Series ◽

10.3354/meps13211 ◽

2020 ◽

Vol 637 ◽

pp. 117-140 ◽

Cited By ~ 1

Author(s):

DW McGowan ◽

ED Goldstein ◽

ML Arimitsu ◽

AL Deary ◽

O Ormseth ◽

...

Keyword(s):

Temporal Dynamics ◽

Marine Ecosystem ◽

Gulf Of Alaska ◽

Data Series ◽

Limited Information ◽

Important Species ◽

Multiple Data ◽

Spatial And Temporal Dynamics ◽

Spawning Areas ◽

Spatio Temporal

Pacific capelin Mallotus catervarius are planktivorous small pelagic fish that serve an intermediate trophic role in marine food webs. Due to the lack of a directed fishery or monitoring of capelin in the Northeast Pacific, limited information is available on their distribution and abundance, and how spatio-temporal fluctuations in capelin density affect their availability as prey. To provide information on life history, spatial patterns, and population dynamics of capelin in the Gulf of Alaska (GOA), we modeled distributions of spawning habitat and larval dispersal, and synthesized spatially indexed data from multiple independent sources from 1996 to 2016. Potential capelin spawning areas were broadly distributed across the GOA. Models of larval drift show the GOA’s advective circulation patterns disperse capelin larvae over the continental shelf and upper slope, indicating potential connections between spawning areas and observed offshore distributions that are influenced by the location and timing of spawning. Spatial overlap in composite distributions of larval and age-1+ fish was used to identify core areas where capelin consistently occur and concentrate. Capelin primarily occupy shelf waters near the Kodiak Archipelago, and are patchily distributed across the GOA shelf and inshore waters. Interannual variations in abundance along with spatio-temporal differences in density indicate that the availability of capelin to predators and monitoring surveys is highly variable in the GOA. We demonstrate that the limitations of individual data series can be compensated for by integrating multiple data sources to monitor fluctuations in distributions and abundance trends of an ecologically important species across a large marine ecosystem.

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Towards a balanced presentation and objective interpretation of acoustic and trawl survey data, with specific reference to the eastern Scotian Shelf

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2016-0113 ◽

2016 ◽

Vol 73 (12) ◽

pp. 1914-1921 ◽

Cited By ~ 4

Author(s):

J. Michael Jech ◽

Ian H. McQuinn

Keyword(s):

Atlantic Cod ◽

Management Strategies ◽

Pelagic Fish ◽

Trophic Levels ◽

Fish Abundance ◽

Forage Fish ◽

Specific Reference ◽

Trawl Survey ◽

Scotian Shelf ◽

Eastern Canada

A debate has developed over the ecosystem consequences following the collapse of Atlantic cod throughout the coastal waters of eastern Canada. The explosive increase in pelagic fish abundance in scientific bottom-trawl catches on the eastern Scotian Shelf has been interpreted as being due to either (i) a “pelagic outburst” of forage fish abundance resulting from predator release or conversely (ii) a change in pelagic fish vertical distribution leading to a “suprabenthic habitat occupation” thereby increasing their availability to bottom trawls. These two interpretations have diametrically opposing ecological consequences and suggest different management strategies for these important forage fish species. We argue that an objective evaluation of the available evidence supports the hypothesis that the abundance of forage fish has not increased in response to the demise of cod and other top predators, and the reliance on a single sampling gear with low catchability has biased and will continue to bias the interpretation of demographic trends of pelagic fish populations. We advocate that multiple sampling technologies providing alternative perspectives are needed for the monitoring and management of the various trophic levels if we are to achieve a balanced and objective understanding of marine ecosystems.

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Genomic and healthcare dynamics of nosocomial SARS-CoV-2 transmission

eLife ◽

10.7554/elife.65453 ◽

2021 ◽

Vol 10 ◽

Author(s):

Jamie M Ellingford ◽

Ryan George ◽

John H McDermott ◽

Shazaad Ahmad ◽

Jonathan J Edgerley ◽

...

Keyword(s):

Infection Control ◽

Temporal Dynamics ◽

Management Strategies ◽

Healthcare Setting ◽

Location Data ◽

Genome Data ◽

Healthcare Settings ◽

Movement Data ◽

Spatial And Temporal Dynamics ◽

Transmission Pathways

Understanding the effectiveness of infection control methods in reducing and preventing SARS-CoV-2 transmission in healthcare settings is of high importance. We sequenced SARS-CoV-2 genomes for patients and healthcare workers (HCWs) across multiple geographically distinct UK hospitals, obtaining 173 high-quality SARS-CoV-2 genomes. We integrated patient movement and staff location data into the analysis of viral genome data to understand spatial and temporal dynamics of SARS-CoV-2 transmission. We identified eight patient contact clusters (PCC) with significantly increased similarity in genomic variants compared to non-clustered samples. Incorporation of HCW location further increased the number of individuals within PCCs and identified additional links in SARS-CoV-2 transmission pathways. Patients within PCCs carried viruses more genetically identical to HCWs in the same ward location. SARS-CoV-2 genome sequencing integrated with patient and HCW movement data increases identification of outbreak clusters. This dynamic approach can support infection control management strategies within the healthcare setting.

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Aquatic hyphomycetes in three rivers of southwestern France. III. Relationships between communities spatial and temporal dynamics

Canadian Journal of Botany ◽

10.1139/b97-157 ◽

1998 ◽

Vol 76 (1) ◽

pp. 115-121

Author(s):

Eric Fabre

Keyword(s):

Correspondence Analysis ◽

Temporal Dynamics ◽

Qualitative Difference ◽

Spatial Dynamics ◽

Aquatic Hyphomycetes ◽

Individual Species ◽

Concentration Data ◽

Spatial And Temporal Dynamics ◽

Conidial Concentration ◽

Three Rivers

Spatial and temporal dynamics of individual species of aquatic hyphomycetes in three southwestern French rivers have been previously studied using water filtration techniques. In this paper, relationships between these spatial and temporal dynamics were explored using correspondence analysis. Correspondence analyses were performed for conidial concentration and presence-absence of species. The analysis of conidial concentration data indicated that species temporal dynamics is more important in determining changes in conidial communities than species spatial dynamics. However, the interconnectedness of these dynamics was revealed by a Guttman effect between the first two factorial axes. A linear gradient Tech-Adour-Nive, which corresponds to the geographical disposition of these rivers in southwestern France, was observed on the first three axes of the correspondence analysis of conidial concentrations. This gradient did not exist in the correspondence analysis of species presence-absence, but the analysis revealed a qualitative difference of the communities between the summer season and the beginning of autumn. The comparison of eigenvalues for the two correspondence analyses pointed out that conidial abundance is more significant than presence-absence of species for the structure of the data table. Key words: aquatic hyphomycete, spatial dynamic, temporal dynamic, climatic gradient.

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Incidence, Spatial Pattern and Temporal Progress of Fusarium Wilt of Bananas

Journal of Fungi ◽

10.3390/jof7080646 ◽

2021 ◽

Vol 7 (8) ◽

pp. 646

Author(s):

Daniel W. Heck ◽

Miguel Dita ◽

Emerson M. Del Ponte ◽

Eduardo S. G. Mizubuti

Keyword(s):

Fusarium Wilt ◽

Temporal Dynamics ◽

Secondary Infection ◽

Regional Scale ◽

Management Strategies ◽

Gompertz Model ◽

Spatial And Temporal Dynamics ◽

Sigmoidal Curve ◽

Average Loss ◽

The Impact

The effective management of Fusarium wilt of bananas (FWB) depends on the knowledge of the disease dynamics in time and space. The objectives of this work were: to estimate disease intensity and impact, and to investigate the spatial and temporal dynamics of FWB. Fields planted with Silk (n = 10), Pome (n = 17), or Cavendish (n = 3) banana subgroups were surveyed in Brazil, totaling 95 ha. In each field, all plants were visually assessed, and diseased plants were georeferenced. The incidence of FWB and the impact of the disease on the yield on a regional scale were estimated. Spatial patterns were analyzed using quadrat- and distance-based methods. FWB incidence ranged from 0.09% to 41.42%, being higher in Silk fields (median = 14.26%). Impacts of epidemics on yield ranged from 18.4 to 8192.5 kg ha−1 year−1, with an average of 1856.7 kg ha−1 year−1. The higher economic impact of the disease was observed on Silk cultivar with an average loss of USD 1974.2 ha−1 year−1. Overall, estimated losses increased on average by USD 109.8 ha−1 year−1 at each 1% of incidence. Aggregation of FWB was detected by all analytical methods in 13 fields (1 of Cavendish, 11 of Pome, and 1 of Silk). In the other 17 fields, at least one analytical method did not reject the null hypothesis of randomness. One field (5 ha), composed of six plots, was selected for spatial and temporal studies during two years with bi-monthly assessments. A sigmoidal curve represented the FWB progress and the Gompertz model best-fitted disease progress. The level of aggregation varied over time, and evidence of secondary infection to neighboring and distant plants was detected. FWB is a widespread problem in Brazil and yield losses can be of high magnitude. Epidemiology-based management strategies can now be better established.

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