scholarly journals Spatio-temporal distribution of spinetail devil ray Mobula mobular in the eastern tropical Atlantic Ocean

2020 ◽  
Vol 43 ◽  
pp. 447-460
Author(s):  
N Lezama-Ochoa ◽  
J Lopez ◽  
M Hall ◽  
P Bach ◽  
F Abascal ◽  
...  

The distribution of the spinetail devil ray Mobula mobular in the eastern tropical Atlantic remains poorly known compared to the Pacific and Indian Oceans. We used fishery-dependent data and generalized additive models to examine the environmental characteristics associated with the presence of M. mobular in the eastern Atlantic Ocean. Results revealed that the distribution of M. mobular is significantly associated with seasonal upwelling systems in coastal and pelagic areas. Our model predicted the presence of the species in areas where there is evidence of its occurrence, such as the Angolan upwelling system and the coast of Ghana. In addition, our model predicted new hotspot areas, including locations around the Mauritanian upwelling system, the Guinea coast, offshore Ghana and the south coast of Angola and Brazil, where sample sizes are limited. Those areas, as well as the environmental preferences depicted by the model, provide valuable information about the habitat and ecology of the spinetail devil ray. Future research lines derived from this study, as well as its limitations, are discussed. Furthermore, in light of our results we discuss the improvements that are needed to contribute to the conservation and management of this vulnerable species.

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251637
Author(s):  
Lauren Kelly Rodriguez ◽  
Amber D. Fandel ◽  
Benjamin R. Colbert ◽  
Jamie C. Testa ◽  
Helen Bailey

Bottlenose dolphins (Tursiops truncatus) are migratory marine mammals that live in both open-ocean and coastal habitats. Although widely studied, little is known about their occurrence patterns in the highly urbanized estuary of the Chesapeake Bay, USA. The goal of this study was to establish the spatial and temporal distribution of bottlenose dolphins throughout this large estuarine system and use statistical modeling techniques to determine how their distribution relates to environmental factors. Three years (April-October 2017–2019) of dolphin sighting reports from a citizen-science database, Chesapeake DolphinWatch, were analyzed. The dolphins had a distinct temporal pattern, most commonly sighted during summer months, peaking in July. This pattern of observed occurrence was confirmed with systematic, passive acoustic detections of dolphin echolocation clicks from local hydrophones. Using spatially-exclusive Generalized Additive Models (GAM), dolphin presence was found to be significantly correlated to spring tidal phase, warm water temperature (24–30°C), and salinities ranging from 6–22 PPT. We were also able to use these GAMs to predict dolphin occurrence in the Bay. These predictions were statistically correlated to the actual number of dolphin sighting reported to Chesapeake DolphinWatch during that time. These models for dolphin presence can be implemented as a predictive tool for species occurrence and inform management of this protected species within the Chesapeake Bay.


2021 ◽  
Author(s):  
Judith Neve ◽  
Guillaume A Rousselet

Sharing data has many benefits. However, data sharing rates remain low, for the most part well below 50%. A variety of interventions encouraging data sharing have been proposed. We focus here on editorial policies. Kidwell et al. (2016) assessed the impact of the introduction of badges in Psychological Science; Hardwicke et al. (2018) assessed the impact of Cognition’s mandatory data sharing policy. Both studies found policies to improve data sharing practices, but only assessed the impact of the policy for up to 25 months after its implementation. We examined the effect of these policies over a longer term by reusing their data and collecting a follow-up sample including articles published up until December 31st, 2019. We fit generalized additive models as these allow for a flexible assessment of the effect of time, in particular to identify non-linear changes in the trend. These models were compared to generalized linear models to examine whether the non-linearity is needed. Descriptive results and the outputs from generalized additive and linear models were coherent with previous findings: following the policies in Cognition and Psychological Science, data sharing statement rates increased immediately and continued to increase beyond the timeframes examined previously, until reaching close to 100%. In Clinical Psychological Science, data sharing statement rates started to increase only two years following the implementation of badges. Reusability rates jumped from close to 0% to around 50% but did not show changes within the pre-policy nor the post-policy timeframes. Journals that did not implement a policy showed no change in data sharing rates or reusability over time. There was variability across journals in the levels of increase, so we suggest future research should examine a larger number of policies to draw conclusions about their efficacy. We also encourage future research to investigate the barriers to data sharing specific to psychology subfields to identify the best interventions to tackle them.


2002 ◽  
Vol 26 (2) ◽  
pp. 206-235 ◽  
Author(s):  
Oliver Korup

More than a decade has passed since the publication of the benchmark paper of Costa and Schuster (Costa, J.E. and Schuster, R.L. 1988: The formation and failure of natural dams. Geological Society of America Bulletin 100, 1054-68) on the formation and failure of natural dams. This review takes a critical look at recent trends and developments in international and New Zealand-based research on landslide dams. Temporary or permanent stream blockages by mass movements commonly occur in steep terrain, and gradually receive more attention and awareness with increasing population and land use pressure in upland regions. Different approaches in methodology and their relevance and application potential for engineering and mitigative measures are reviewed and several shortcomings outlined, with a view towards possible future research directions. A high percentage of previous work on landslide dams has been mainly descriptive in character, and has produced a multitude of documented case studies. Recent attempts to redress the balance have included the establishment of global and nationwide databases (inventories) of landslide dams, progress in predictive, quantitative and GIS-based modelling. Furthermore, interpretative approaches towards the reconstruction of former stream blockages and their spatio-temporal distribution patterns have been pursued, which may assist assessments of present and future geomorphic hazards. Both such appraisals as well as management strategies in mountainous regions in general, will have to rely on key data efficiently extracted from a plethora of case examples. Further work includes consideration of temporal and permanent landslide-triggered stream impoundments within Quaternary landscape evolution, quantification of sediment budgets and palaeoenvironmental reconstruction. Overall, there is still a considerable lack of understanding of geomorphic forms and processes involved with landslide-dam formation, stability and failure, part of which is inherent in the often ephemeral nature of stream blockages in coupled hillslope-valley systems.


Oryx ◽  
2019 ◽  
pp. 1-11 ◽  
Author(s):  
Kristen Denninger Snyder ◽  
Philemon Mneney ◽  
Benson Benjamin ◽  
Peter Mkilindi ◽  
Noel Mbise

Abstract In the western Serengeti of Tanzania, African elephant Loxodonta africana populations are increasing, which is rare across the species’ range. Here, conservation objectives come into conflict with competing interests such as agriculture. Elephants regularly damage crops, which threatens livelihoods and undermines local support for conservation. For damage reduction efforts to be successful, limited resources must be used efficiently and strategies for mitigation and prevention should be informed by an understanding of the spatial and temporal distribution of crop damage. We assessed historical records of crop damage by elephants to describe the dynamics and context of damage in the western Serengeti. We used binary data and generalized additive models to predict the probability of crop damage at the village level in relation to landscape features and metrics of human disturbance. During 2012–2014 there were 3,380 reports of crop damage by elephants submitted to authorities in 42 villages. Damage was concentrated in villages adjacent to a reserve boundary and peaked during periods of crop maturity and harvest. The village-level probability of crop damage was negatively associated with distance from a reserve, positively with length of the boundary shared with a reserve, and peaked at moderate levels of indicators of human presence. Spatially aggregated historical records can provide protected area managers and regional government agencies with important insights into the distribution of conflict across the landscape and between seasons, and can guide efforts to optimize resource allocation and future land use planning efforts.


2020 ◽  
Vol 655 ◽  
pp. 171-183
Author(s):  
EE Becerril-García ◽  
RO Martínez-Rincón ◽  
F Galván-Magaña ◽  
O Santana-Morales ◽  
EM Hoyos-Padilla

Guadalupe Island, Mexico, is one of the most important white shark (Carcharodon carcharias) aggregation sites in the Eastern Pacific. In the waters surrounding Guadalupe Island, cage diving has been carried out since 2001 during August-November; however, there is scarce information regarding the factors associated with this seasonal aggregation. The purpose of this study was to describe the probability of occurrence of white sharks relative to spatial, temporal, and environmental factors in Guadalupe Island. Generalized additive models (GAMs) were used to describe the effect of sea surface temperature, water visibility, tide, moon phase, cloud cover, time of day, and location on white shark occurrence. GAMs were generated from a data set of 6266 sightings of white sharks, classified as immature males, mature males, immature females, and mature females. A sexual segregation related to month was observed, where females arrived after males during late September. GAMs evidenced a segregation of white sharks according to the analysed variables, which is consistent with previous observations in this locality. Environmental preferences for each white shark category are potentially influenced by feeding habits, sexual maturation, and reproduction. This study constitutes a baseline of the effect of the environment on the occurrence of white sharks in Guadalupe Island, which can be used in further studies regarding management and conservation in future climatic and anthropogenic scenarios. Its relevance is related to the understanding of its ecology in oceanic environments and the presence of this threatened species during the ecotourism season.


2010 ◽  
Vol 67 (8) ◽  
pp. 1553-1564 ◽  
Author(s):  
Juan P. Zwolinski ◽  
Paulo B. Oliveira ◽  
Victor Quintino ◽  
Yorgos Stratoudakis

Abstract Zwolinski, J. P., Oliveira, P. B., Quintino, V., and Stratoudakis, Y. 2010. Sardine potential habitat and environmental forcing off western Portugal. – ICES Journal of Marine Science, 67: 1553–1564. Relationships between sardine (Sardina pilchardus) distribution and the environment off western Portugal were explored using data from seven acoustic surveys (spring and autumn of 2000, 2001, 2005, and spring 2006). Four environmental variables (salinity, temperature, chlorophyll a, and acoustic epipelagic backscatter other than fish) were related to the acoustic presence and density of sardine. Univariate quotient analysis revealed sardine preferences for waters with high chlorophyll a content, low temperature and salinity, and low acoustic epipelagic backscatter. Generalized additive models depicted significant relationships between the environment and sardine presence but not with sardine density. Maps of sardine potential habitat (SPH) built upon the presence/absence models revealed a clear seasonal effect in the across-bathymetry and alongshelf extension of SPH off western Portugal. During autumn, SPH covered a large part of the northern Portuguese continental shelf but was almost absent from the southern region, whereas in spring SPH extended farther south but was reduced to a narrow band of shallow coastal waters in the north. This seasonal pattern agrees with the spatio-temporal variation of primary production and oceanic circulation described for the western Iberian shelf.


2021 ◽  
Vol 15 (12) ◽  
pp. e0009980
Author(s):  
Weerapong Thanapongtharm ◽  
Sarin Suwanpakdee ◽  
Arun Chumkaeo ◽  
Marius Gilbert ◽  
Anuwat Wiratsudakul

The situation of human rabies in Thailand has gradually declined over the past four decades. However, the number of animal rabies cases has slightly increased in the last ten years. This study thus aimed to describe the characteristics of animal rabies between 2017 and 2018 in Thailand in which the prevalence was fairly high and to quantify the association between monthly rabies occurrences and explainable variables using the generalized additive models (GAMs) to predict the spatial risk areas for rabies spread. Our results indicate that the majority of animals affected by rabies in Thailand are dogs. Most of the affected dogs were owned, free or semi-free roaming, and unvaccinated. Clusters of rabies were highly distributed in the northeast, followed by the central and the south of the country. Temporally, the number of cases gradually increased after June and reached a peak in January. Based on our spatial models, human and cattle population density as well as the spatio-temporal history of rabies occurrences, and the distances from the cases to the secondary roads and country borders are identified as the risk factors. Our predictive maps are applicable for strengthening the surveillance system in high-risk areas. Nevertheless, the identified risk factors should be rigorously considered and integrated into the strategic plans for the prevention and control of animal rabies in Thailand.


2019 ◽  
Vol 66 (1) ◽  
Author(s):  
Yan Jin ◽  
Zun-Lei Liu ◽  
Jian-Hua Tang ◽  
Yong Liu

Understanding the spatial distribution and environmental characteristics of fish spawning grounds is essential to design effective fishery management. The half-fin anchovy Setipinna taty (Valenciennes, 1848) plays an important role in the marine food web. A survey with 54 stations was conducted in 2014 to study the spatio-temporal distribution of eggs and larvae of half-fin anchovy around the inshore waters of Jiangsu, China. Half-fin anchovy eggs, larvae and juveniles were collected every month from April to July 2014. Generalised additive models were used to investigate the relationship between distribution of eggs, larvae and juveniles and environmental variables. A total of 4150 eggs and 685 half-fin anchovy larvae and juveniles were caught during the survey. During the spawning season, the highest egg densities were located in the inshore water area (121°-122°E, 32.5-33.5°N), with no significant shift in location of egg densities through time. The distribution of larvae and juveniles mostly overlapped with the egg distribution, suggesting that the early life stage of half-fin anchovy are distributed within the inshore waters of Jiangsu. The optimal water temperature, salinity and depth for eggs and larvae were in the range of 14.0-24.6°C, 28.7-29.8 ‰ and 15.9-17.4 m, respectively.


2020 ◽  
Vol 10 (8) ◽  
pp. 3091-3110 ◽  
Author(s):  
M. E. Wigwe ◽  
E. S. Bougre ◽  
M. C. Watson ◽  
A. Giussani

Abstract Modern data analytic techniques, statistical and machine-learning algorithms have received widespread applications for solving oil and gas problems. As we face problems of parent–child well interactions, well spacing, and depletion concerns, it becomes necessary to model the effect of geology, completion design, and well parameters on production using models that can capture both spatial and temporal variability of the covariates on the response variable. We accomplish this using a well-formulated spatio-temporal (ST) model. In this paper, we present a multi-basin study of production performance evaluation and applications of ST models for oil and gas data. We analyzed dataset from 10,077 horizontal wells from 2008 to 2019 in five unconventional formations in the USA: Bakken, Marcellus, Eagleford, Wolfcamp, and Bone Spring formations. We evaluated well production performance and performance of new completions over time. Results show increased productivity of oil and gas since 2008. Also, the Bakken wells performed better for the counties evaluated. We present two methods for fitting spatio-temporal models: fixed rank kriging and ST generalized additive models using thin plate and cubic regression splines as basis functions in the spline-based smooths. Results show a significant effect on production by the smooth term, accounting for between 60 and 95% of the variability in the six-month production. Overall, we saw a better production response to completions for the gas formations compared to oil-rich plays. The results highlight the benefits of spatio-temporal models in production prediction as it implicitly accounts for geology and technological changes with time.


Phytotaxa ◽  
2019 ◽  
Vol 420 (1) ◽  
pp. 79-83
Author(s):  
HELEN MICHELLE DE JESUS AFFE ◽  
JOSÉ MARCOS DE CASTRO NUNES ◽  
LUIS ANTÔNIO DE OLIVEIRA PROENÇA ◽  
RENATA STOCK FONSECA ◽  
MARIÂNGELA MENEZES

The genus Metadinophysis was proposed by Nie & Wang (1941) based on their description of the new species Metadinophysis sinensis Nie & Wang, from collections in Ching-lan Bay, Hainan Province, China. In addition to the Pacific Ocean, coastal waters of Japan, Thailand, and Vietnam, the genus was recorded for the southern coast of Myanmar (Su-Myat et al. 2012) and more recently in New Caledonia (Chomérat 2016).  The present study constitutes the first record of Metadinophysis sinensis for the tropical Atlantic Ocean, from collections made in five coastal systems located in the coast of Bahia (13°01’30” S and 038°34’40” W, 13°52’44” S and 038°57’58” W), northeastern Brazil (Fig. 1).


Sign in / Sign up

Export Citation Format

Share Document