Assessing surf-zone fish assemblage variability in southern Brazil

2015 ◽  
Vol 66 (2) ◽  
pp. 106 ◽  
Author(s):  
Fábio L. Rodrigues ◽  
Henrique N. Cabral ◽  
João P. Vieira
Keyword(s):  
Species Richness ◽  
Fish Assemblage ◽  
Large Scale ◽  
Linear Models ◽  
Surf Zone ◽  
Poisson Model ◽  
Sandy Beaches ◽  
Southern Brazil ◽  
Beach Seine ◽  
Explanatory Variables

Surf-zone fish assemblage was investigated to assess its patterns of variability for two sandy beaches in southern Brazil. Fish were collected monthly (July 2009–June 2011), and the hauls were conducted with two different beach seine nets. Generalized linear models were used in the following two different approaches: (1) a Poisson model was used to assess and compare fish species richness; and (2) a logistic and gamma models were used to explain the occurrence and variability in abundance of Mugil liza and Trachinotus marginatus (dominant species). A set of nine explanatory variables was used to explain the patterns of ecological variability. At a large scale, seven variables explain 24.8% of the variance in species richness; and season (16.2%) and beach seine (3.0%) were the most important. The presence of M. liza was associated with beach seine (20.4%), whereas the abundance was associated with beach seine (12.1%) and five other explanatory variables. The presence and abundance of T. marginatus was associated with season (18.6% and 22.3%, respectively). Species richness seems to be strongly related to season, although the choice of net used can play an important role. Warmer months are richer in number of species, and the larger net is able to catch more species than the smaller one.

scholarly journals APPLICABILITY OF SUSPENDED SEDIMENT CONCENTRATION FORMULAE TO LARGE-SCALE BEACH MORPHOLOGICAL CHANGES

2012 ◽  
Vol 1 (33) ◽  
pp. 57 ◽  
Author(s):  
Ravindra Jayaratne ◽  
Yasufumi Takayama ◽  
Tomoya Shibayama
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Surf Zone ◽  
Morphological Changes ◽  
Current Model ◽  
Sediment Concentration ◽  
Sandy Beaches ◽  
Propagation Model ◽  
Deformation Model ◽  
Seabed Sediment

Study of beach morphological changes under storm conditions and its prediction capability are of paramount importance in coastal zone management. Seabed sediment is picked up violently in and outside the surf zone due to suspension mechanisms, therefore a considerable amount of sand is transported in coastal waters due to such mechanisms. For the construction of an accurate beach morphological model, it is necessary to elucidate the sediment suspension and to introduce it properly into the modelling of sediment transport. Jayaratne and Shibayama (2007) developed a complete set of explicit theoretical formulae to predict the time-averaged concentration on sandy beaches due to three suspension mechanisms: a) vortical motion over wave-generated sand ripples, b) from sheet flow, and c) turbulent motion under breaking waves. The present paper focuses on the development of a quasi-3D beach deformation model using the sediment concentration models of Jayaratne and Shibayama (2007), the bed load model of Watanabe (1982), the wave propagation model of Onaka et al. (1988), the nearshore current model of Philips (1977) and the undertow model of Okayasu et al. (1990) to predict the large-scale morphodynamics of sandy beaches. The predicted beach profiles and total sediment transport rates were compared with two sets of large-scale laboratory experimental data [Kajima et al. (1983); Kraus and Larson (1988)] and Seisho beach at Kanagawa Prefecture, Japan. It can be concluded that the present numerical model is capable of predicting sediment transport direction, on-offshore sand bar formation and the general trend of the beach profiles of large-scale erosive- and accretive-type sandy beaches to a satisfactory level.

scholarly journals Models of alien species richness show moderate predictive accuracy and poor transferability

NeoBiota ◽  
2018 ◽  
Vol 38 ◽  
pp. 77-96 ◽  
Author(s):  
César Capinha ◽  
Franz Essl ◽  
Hanno Seebens ◽  
Henrique Miguel Pereira ◽  
Ingolf Kühn
Keyword(s):  
Species Richness ◽  
Alien Species ◽  
Linear Models ◽  
Negative Binomial ◽  
Predictive Accuracy ◽  
Multivariate Adaptive Regression Splines ◽  
Boosted Regression Trees ◽  
Data Sets ◽  
Explanatory Variables ◽  
Taxonomic Groups

Robust predictions of alien species richness are useful to assess global biodiversity change. Nevertheless, the capacity to predict spatial patterns of alien species richness remains largely unassessed. Using 22 data sets of alien species richness from diverse taxonomic groups and covering various parts of the world, we evaluated whether different statistical models were able to provide useful predictions of absolute and relative alien species richness, as a function of explanatory variables representing geographical, environmental and socio-economic factors. Five state-of-the-art count data modelling techniques were used and compared: Poisson and negative binomial generalised linear models (GLMs), multivariate adaptive regression splines (MARS), random forests (RF) and boosted regression trees (BRT). We found that predictions of absolute alien species richness had a low to moderate accuracy in the region where the models were developed and a consistently poor accuracy in new regions. Predictions of relative richness performed in a superior manner in both geographical settings, but still were not good. Flexible tree ensembles-type techniques (RF and BRT) were shown to be significantly better in modelling alien species richness than parametric linear models (such as GLM), despite the latter being more commonly applied for this purpose. Importantly, the poor spatial transferability of models also warrants caution in assuming the generality of the relationships they identify, e.g. by applying projections under future scenario conditions. Ultimately, our results strongly suggest that predictability of spatial variation in richness of alien species richness is limited. The somewhat more robust ability to rank regions according to the number of aliens they have (i.e. relative richness), suggests that models of aliens species richness may be useful for prioritising and comparing regions, but not for predicting exact species numbers.

scholarly journals Occurrence and abundance of young mullet Mugil liza (Teleostei: Mugilidae) in the surf zone along the southern coast of Brazil

2021 ◽  
Vol 85 (4) ◽  
pp. 245-255
Author(s):  
Valéria Marques Lemos ◽  
Henrique Cabral ◽  
Stephanie Pasquaud ◽  
João Paes Vieira
Keyword(s):  
Generalized Linear Models ◽  
Low Temperatures ◽  
Environmental Variables ◽  
Linear Models ◽  
Surf Zone ◽  
Sampling Period ◽  
Southern Population ◽  
Southern Brazil ◽  
Probability Of Occurrence ◽  
Temporary Habitat

The southern population of Mugil liza is distributed from Argentina (47°S) to the state of São Paulo, Brazil (23°S). Young mullets use the estuaries as nursery grounds, and prior to recruitment into estuaries they use the surf zone as a temporary habitat. Based on 12 consecutive months of sampling, this study used generalized linear models (GLM) to analyse the relationships between environmental variables and the presence and relative abundance of young mullets in the surf zone adjacent to six major estuaries in southern Brazil (between 29°S and 33°S). Young mullets were present in all seasons over the sampling period, but the probability of occurrence was higher in winter and was associated with low temperatures. The water temperature alone explained more than half of the total deviance of the GLM models for presence (23%) and abundance (21%) of young mullets in the surf zone. Site 2 (Rio Grande) had lower temperatures in the colder months, the highest probability of occurrence of all collection sites and the greatest abundance (n=3402) of young M. liza, which represented 52% of the total of individuals (n=6493) caught among the six sites sampled.

scholarly journals Numerical modelling of intra-wave sediment transport on sandy beaches using a non-hydrostatic, wave-resolving model

2020 ◽  
Vol 71 (1) ◽  
pp. 1-20
Author(s):  
Giulia Mancini ◽  
Riccardo Briganti ◽  
Robert McCall ◽  
Nicholas Dodd ◽  
Fangfang Zhu
Keyword(s):  
Sediment Transport ◽  
Numerical Modelling ◽  
Large Scale ◽  
Surf Zone ◽  
Sediment Concentration ◽  
Sandy Beaches ◽  
Swash Zone ◽  
Transport Modelling ◽  
Wave Trains ◽  
Sediment Transport Modelling

AbstractThe mutual feedback between the swash zone and the surf zone is known to affect large-scale morphodynamic processes such as breaker bar migration on sandy beaches. To fully resolve this feedback in a process-based manner, the morphodynamics in the swash zone and due to swash-swash interactions must be explicitly solved, e.g., by means of a wave-resolving numerical model. Currently, few existing models are able to fully resolve the complex morphodynamics in the swash zone, and none is practically applicable for engineering purposes. This work aims at improving the numerical modelling of the intra-wave sediment transport on sandy beaches in an open-source wave-resolving hydro-morphodynamic framework (e.g., non-hydrostatic XBeach). A transport equation for the intra-wave suspended sediment concentration, including an erosion and a deposition rate, is newly implemented in the model. Two laboratory experiments involving isolated waves and wave trains are simulated to analyse the performance of the model. Numerical results show overall better performance in simulating single waves rather than wave trains. For the latter, the modelling of the morphodynamic response improves in the swash zone compared with the existing sediment transport modelling approach within non-hydrostatic XBeach, while the need of including additional physical processes to better capture sediment transport and bed evolution in the surf zone is highlighted in the paper.

Surf zone fish abundance and diversity at two sandy beaches separated by long rocky jetties

2012 ◽  
Vol 93 (4) ◽  
pp. 867-875 ◽  
Author(s):  
Fábio Lameiro Rodrigues ◽  
João Paes Vieira
Keyword(s):  
Fish Assemblage ◽  
Surf Zone ◽  
Fish Assemblages ◽  
Species Abundance ◽  
Sandy Beaches ◽  
Fish Abundance ◽  
Fish Assemblage Structure ◽  
Fish Community Structure ◽  
Abundance And Diversity ◽  
Odontesthes Argentinensis

In this work, we evaluated the influence of long rocky jetties (~5 km) on fish abundance and diversity between sheltered and exposed marine sandy beaches. We also described and compared the fish community structure and investigated the relationships between environmental variables and fish assemblages. Fish were collected monthly with a beach seine net from May 2001 to May 2002 at the Cassino and Mar Grosso beaches. Twenty-nine taxa were caught and the fish assemblage showed similar composition between beaches (Sj = 62.1%; %Min = 52.3%), with 18 species in common. Most of the fish were juveniles, mainly young-of-the-year with sizes ≤60 mm total length. Eight species (Trachinotus marginatus, Mugil liza, Brevoortia pectinata, Menticirrhus littoralis, Menticirrhus americanus, Odontesthes argentinensis and Oncopterus darwinii) were the most abundant, accounting for 95.6% of the total catch. At both beaches, only T. marginatus, M. liza and M. littoralis were frequent and abundant, but with some differences in their relative abundance. The canonical correspondence analysis results showed that temperature had the highest correlation with fish abundance. Seasonal changes in fish assemblage structure were evident, with a greater species diversity and abundance in the spring and summer. The overall results indicate that the presence of jetties had no effect on fish assemblages of adjacent sandy beaches. Moreover, differences between beaches were related to some species abundance and not to differences in the number and composition of species between beaches.

scholarly journals The Relationships Between Serum DHEA-S and AMH Levels in Infertile Women: A Retrospective Cross-Sectional Study

2021 ◽  
Vol 10 (6) ◽  
pp. 1211
Author(s):  
Li-Te Lin ◽  
Kuan-Hao Tsui
Keyword(s):  
Generalized Linear Models ◽  
Large Scale ◽  
Linear Models ◽  
Positive Association ◽  
Cross Sectional Study ◽  
Dehydroepiandrosterone Sulphate ◽  
Sectional Study ◽  
Cross Sectional ◽  
Infertile Women ◽  
The Relationship

The relationship between serum dehydroepiandrosterone sulphate (DHEA-S) and anti-Mullerian hormone (AMH) levels has not been fully established. Therefore, we performed a large-scale cross-sectional study to investigate the association between serum DHEA-S and AMH levels. The study included a total of 2155 infertile women aged 20 to 46 years who were divided into four quartile groups (Q1 to Q4) based on serum DHEA-S levels. We found that there was a weak positive association between serum DHEA-S and AMH levels in infertile women (r = 0.190, p < 0.001). After adjusting for potential confounders, serum DHEA-S levels positively correlated with serum AMH levels in infertile women (β = 0.103, p < 0.001). Infertile women in the highest DHEA-S quartile category (Q4) showed significantly higher serum AMH levels (p < 0.001) compared with women in the lowest DHEA-S quartile category (Q1). The serum AMH levels significantly increased across increasing DHEA-S quartile categories in infertile women (p = 0.014) using generalized linear models after adjustment for potential confounders. Our data show that serum DHEA-S levels are positively associated with serum AMH levels.

scholarly journals EEG Data Quality: Determinants and Impact in a Multicenter Study of Children, Adolescents, and Adults with Attention-Deficit/Hyperactivity Disorder (ADHD)

2021 ◽  
Vol 11 (2) ◽  
pp. 214
Author(s):  
Anna Kaiser ◽  
Pascal-M. Aggensteiner ◽  
Martin Holtmann ◽  
Andreas Fallgatter ◽  
Marcel Romanos ◽  
...  
Keyword(s):  
Data Quality ◽  
Large Scale ◽  
Linear Models ◽  
Spectral Power ◽  
Control Group ◽  
Continuous Performance Task ◽  
Related Data ◽  
Eyes Closed ◽  
Eeg Data ◽  
Eyes Open

Electroencephalography (EEG) represents a widely established method for assessing altered and typically developing brain function. However, systematic studies on EEG data quality, its correlates, and consequences are scarce. To address this research gap, the current study focused on the percentage of artifact-free segments after standard EEG pre-processing as a data quality index. We analyzed participant-related and methodological influences, and validity by replicating landmark EEG effects. Further, effects of data quality on spectral power analyses beyond participant-related characteristics were explored. EEG data from a multicenter ADHD-cohort (age range 6 to 45 years), and a non-ADHD school-age control group were analyzed (ntotal = 305). Resting-state data during eyes open, and eyes closed conditions, and task-related data during a cued Continuous Performance Task (CPT) were collected. After pre-processing, general linear models, and stepwise regression models were fitted to the data. We found that EEG data quality was strongly related to demographic characteristics, but not to methodological factors. We were able to replicate maturational, task, and ADHD effects reported in the EEG literature, establishing a link with EEG-landmark effects. Furthermore, we showed that poor data quality significantly increases spectral power beyond effects of maturation and symptom severity. Taken together, the current results indicate that with a careful design and systematic quality control, informative large-scale multicenter trials characterizing neurophysiological mechanisms in neurodevelopmental disorders across the lifespan are feasible. Nevertheless, results are restricted to the limitations reported. Future work will clarify predictive value.

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