117 research outputs found
Evidence of environmental niche separation between threatened mobulid rays in Aotearoa New Zealand: Insights from species distribution modelling
\ua9 2024 The Author(s). Journal of Biogeography published by John Wiley & Sons Ltd.Aim: Mobulid rays are a group of threatened batoid fishes susceptible to population decline from targeted fisheries and accidental capture. Spatial distributions of mobulid rays remain poorly known. Prior studies found commonalities between favourable environments and prey among various mobulid species, yet most were conducted in tropical waters. To explore the habitat use and distribution of mobulid rays in a temperate environment we model the habitat suitability of two mobulid rays (Mobula mobular and Mobula birostris) in Aotearoa New Zealand using fisheries and citizen science occurrence data spanning almost two decades. Location: Northeastern coast of Aotearoa, New Zealand. Methods: Boosted Regression Tree models were used to predict the annual habitat suitability and favourable environmental conditions of the two species based on available sightings records in conjunction with high resolution (1 km2) environmental data. Results: The sympatric study species had contrasting habitat requirements. We found a separation in their spatial distribution defined by the 200 m isobath – the onshore extent for M. birostris and the offshore extent for M. mobular. While there were only subtle variations in relative habitat suitability for M. mobular over the study period, M. birostris exhibited greater interannual variability. Despite differing interannual patterns, spatial separation, as a function of environmental properties, persisted regardless of the year. Main Conclusions: Our results suggest that associations between mobulid species may differ from tropical regions due to regional adaptations to prey availability or local environmental conditions unique to colder and more productive temperate waters. Our findings highlight the importance of multi-species surveys and the inclusion of temporal variability in support of separate species-specific management plans to account for differing stressors impacting each species
Drivers of Spatial Distributions of Basking Shark (<em>Cetorhinus maximus</em>) in the Southwest Pacific
Using joint species distribution modelling to predict distributions of seafloor taxa and identify vulnerable marine ecosystems in New Zealand waters
\ua9 The Author(s) 2024.Effective ecosystem-based management of bottom-contacting fisheries requires understanding of how disturbances from fishing affect seafloor fauna over a wide range of spatial and temporal scales. Spatial predictions of abundance for 67 taxa were developed, using an extensive dataset of faunal abundances collected using a towed camera system and spatially explicit predictor variables including bottom-trawl fishing effort, using a Joint Species Distribution Model (JSDM). The model fit metrics varied by taxon: the mean tenfold cross-validated AUC score was 0.70 \ub1 0.1 (standard deviation) for presence–absence and an R2 of 0.11 \ub1 0.1 (standard deviation) for abundance models. Spatial predictions of probability of occurrence and abundance (individuals per km2) varied by taxon, but there were key areas of overlap, with highest predicted taxon richness in areas of the continental shelf break and slope. The resulting joint predictions represent significant advances on previous predictions because they are of abundance, allow the exploration of co-occurrence patterns and provide credible estimates of taxon richness (including for rare species that are often not included in more commonly used single-species distribution modelling). Habitat-forming taxa considered to be Vulnerable Marine Ecosystem (VME) indicators (those taxa that are physically or functionally fragile to anthropogenic impacts) were identified in the dataset. Spatial estimates of likely VME distribution (as well as associated estimates of uncertainty) were predicted for the study area. Identifying areas most likely to represent a VME (rather than simply VME indicator taxa) provides much needed quantitative estimates of vulnerable habitats, and facilitates an evidence-based approach to managing potential impacts of bottom-trawling
Procesos de profesionalización en torno al gerenciamiento liderazgo del talento humano
Luego de cinco ediciones del Programa de Posgrado “Gerenciamiento y Liderazgo del Talento Humano” de la FCECO de la UNER, se ha generado un Observatorio de Buenas Prácticas Gerenciales para el seguimiento de los procesos de profesionalización en torno al gerenciamiento y el liderazgo del talento de los profesionales que han cursado dicho Posgrado. Lo relevado en el Observatorio es uno de los insumos para este Proyecto, en el cual se analizan los impactos en el desempeño profesional, en términos de sinergias en los equipos de trabajo. La Hipótesis que se trabaja es la existencia de fuertes repercusiones en los entornos laborales donde los cursantes desarrollan sus actividades, a partir del cursado de la propuesta. Se analiza la importancia de profesionalizarse en el diálogo cooperativo para desarrollar las tareas alineándolas con los objetivos de la organización. El trabajo apunta a conocer las razones por las que los profesionales deciden continuar sus estudios de posgrado, describir en qué medida el paso por las aulas de posgrado tuvieron impacto en sus procesos de profesionalización, recuperar las percepciones en cuanto a la valoración que los egresados del programa hacen de la formación recibida en relación al mejoramiento de su profesionalidad y desarrollo personal.
ARK: http://id.caicyt.gov.ar/ark:/s22504559/i3aqn7gd
Squalus acanthias, spiny dogfish
While there are reported subpopulations of Squalus acanthias (Linnaeus, 1758) elsewhere in the world, the North Pacific subpopulation is now considered a separate species, Squalus suckleyi (Girard, 1854) (see Ebert et al. 2010). Further taxonomic studies on this genus are required, including in relation to Mediterranean and Black Sea subpopulations. In Europe, three subpopulations are inferred to occur.Fil: Finucci, B.. National Institute of Water and Atmospheric Research; Nueva ZelandaFil: Cheok, J.. University Fraser Simon; CanadáFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cotton, C. F.. Florida State University; Estados UnidosFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Kulka, D. W.. No especifíca; ArgentinaFil: Neat, F. C.. No especifíca; ArgentinaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Rigby, C. L.. James Cook University; AustraliaFil: Tanaka, S.. No especifíca; ArgentinaFil: Walker, T. I.. University of Melbourne; Australi
Overfishing and habitat loss drive range contraction of iconic marine fishes to near extinction
Extinctions on land are often inferred from sparse sightings over time, but this technique is ill-suited for wide-ranging species. We develop a space-for-time approach to track the spatial contraction and drivers of decline of sawfishes. These iconic and endangered shark-like rays were once found in warm, coastal waters of 90 nations and are now presumed extinct in more than half (n = 46). Using dynamic geography theory, we predict that sawfishes are gone from at least nine additional nations. Overfishing and habitat loss have reduced spatial occupancy, leading to local extinctions in 55 of the 90 nations, which equates to 58.7% of their historical distribution. Retention bans and habitat protections are urgently necessary to secure a future for sawfishes and similar species
An atlas of seabed biodiversity for Aotearoa New Zealand
\ua9 2023 Copernicus GmbH. All rights reserved. The waters of Aotearoa New Zealand span over 4.2ĝ€\uafmillionĝ€\uafkm2 of the South Pacific Ocean and harbour a rich diversity of seafloor-Associated taxa. Due to the immensity and remoteness of the area, there are significant gaps in the availability of data that can be used to quantify and map the distribution of seafloor and demersal biodiversity, limiting effective management. In this study, we describe the development and accessibility of an online atlas of seabed biodiversity that aims to fill these gaps. Species distribution models were developed for 579 taxa across four taxonomic groups: demersal fish, reef fish, subtidal invertebrates and macroalgae. Spatial layers for taxa distribution based on habitat suitability were statistically validated and then, as a further check, evaluated by taxonomic experts to provide measures of confidence to guide the future use of these layers. Spatially explicit uncertainty (SD) layers were also developed for each taxon distribution. We generated layer-specific metadata, including statistical and expert evaluation scores, which were uploaded alongside the accompanying spatial layers to the open access database Zenodo. This database provides the most comprehensive source of information on the distribution of seafloor taxa for Aotearoa New Zealand and is thus a valuable resource for managers, researchers and the public that will guide the management and conservation of seafloor communities. The atlas of seabed biodiversity for Aotearoa New Zealand is freely accessible via the open-Access database Zenodo under 10.5281/zenodo.7083642 (Stephenson et al., 2022)
Carcharhinus hemiodon Pondicherry Shark
The Pondicherry Shark (Carcharhinus hemiodon) is a small (to 102 cm total length) and very rare Indo-
West Pacific whaler shark. It has a wide historic range from Oman to southern China, but known records
are scattered, and it has only been reliably verified from a handful of countries. It appears to occur in
shallow coastal waters, and has also been reported to enter rivers, although this has not been verified.
The contemporary range of this species is poorly defined and museum specimens were collected pre-
1960. There are reports from 1979, the 1990s, and 2000, but none of these could be verified. Its
identification is problematic, and it is easily confused with a number of other Carcharhinus species (for
example, recent putative records from Sri Lanka)
Overfishing Drives Over One-Third of All Sharks and Rays Toward a Global Extinction Crisis
The scale and drivers of marine biodiversity loss are being revealed by the International Union for Conservation of Nature (IUCN) Red List assessment process. We present the first global reassessment of 1,199 species in Class Chondrichthyes-sharks, rays, and chimeras. The first global assessment (in 2014) concluded that one-quarter (24%) of species were threatened. Now, 391 (32.6%) species are threatened with extinction. When this percentage of threat is applied to Data Deficient species, more than one-third (37.5%) of chondrichthyans are estimated to be threatened, with much of this change resulting from new information. Three species are Critically Endangered (Possibly Extinct), representing possibly the first global marine fish extinctions due to overfishing. Consequently, the chondrichthyan extinction rate is potentially 25 extinctions per million species years, comparable to that of terrestrial vertebrates. Overfishing is the universal threat affecting all 391 threatened species and is the sole threat for 67.3% of species and interacts with three other threats for the remaining third: loss and degradation of habitat (31.2% of threatened species), climate change (10.2%), and pollution (6.9%). Species are disproportionately threatened in tropical and subtropical coastal waters. Science-based limits on fishing, effective marine protected areas, and approaches that reduce or eliminate fishing mortality are urgently needed to minimize mortality of threatened species and ensure sustainable catch and trade of others. Immediate action is essential to prevent further extinctions and protect the potential for food security and ecosystem functions provided by this iconic lineage of predators
Large-scale assessments of bottom trawling effects on Vulnerable Marine Ecosystems can significantly under-represent impacts
\ua9 2025 The Author(s). Bottom trawling threatens Vulnerable Marine Ecosystems (VMEs). We evaluated historic benthic trawling impacts on 10 VME indicator taxa (e.g. cold-water corals) and estimates of VME distribution (based on the overlap of taxa abundance-based and richness-based indices) across New Zealand waters, using a dynamic Relative Benthic Status model, incorporating 30 years of fishing data, and taxon-specific depletion and recovery rates. The analysis was conducted at a national scale and within six ecologically relevant bioregional scales. We predicted severe, lasting impacts at bioregional levels, despite modest national-scale effects. All VME indicator taxa fell below an 80% \u27good ecosystem state\u27 threshold in at least one bioregion, with VMEs in three of six bioregions below this critical limit. Combined with limited observed recovery for these taxa 20–40 years post-fishing, these impacts likely represent Significant Adverse Impacts. By integrating high-resolution spatial predictions with long-term impact assessments at ecologically relevant scales, our approach provides a novel replicable framework for regional and global assessments, identifying pristine areas vital for conservation under agreements like the High Seas Treaty. This study is an important step towards sustainable fisheries management and marine biodiversity conservation, providing essential insights to guide policy decisions and protect the oceans\u27 most vulnerable ecosystems from bottom trawling
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