scholarly journals Singing Fin Whale Swimming Behavior in the Central North Pacific

2021 ◽  
Vol 8 ◽  
Author(s):  
Regina A. Guazzo ◽  
Ian N. Durbach ◽  
Tyler A. Helble ◽  
Gabriela C. Alongi ◽  
Cameron R. Martin ◽  
...  
Keyword(s):  
Markov Models ◽  
Generalized Additive Models ◽  
Time Of Day ◽  
Swimming Behavior ◽  
Additive Models ◽  
Sea State ◽  
Fin Whale ◽  
Singing Behavior ◽  
Fin Whales ◽  
Passive Acoustic

Male fin whales sing using 20 Hz pulses produced in regular patterns of inter-note intervals, but little is known about fin whale swimming behavior while they are singing. Even less is known about fin whales in Hawaiian waters because they have rarely been sighted during surveys and passive acoustic monitoring has been limited to sparse hydrophone systems that do not have localization capabilities. We hypothesized that fin whale kinematics may be related to their singing behavior, or external variables such as time and sea state. To investigate this hypothesis, we analyzed 115 tracks containing 50,034 unique notes generated from passive acoustic recordings on an array of 14 hydrophones from 2011 to 2017 at the U.S. Navy Pacific Missile Range Facility off Kauai, Hawaii. Fin whales swam at an average speed of 1.1 m/s over relatively direct paths. We incorporated the whales' speed and turning angle into hidden Markov models to identify different behavioral states based on the whales' movements. We found that fin whale kinematic behavioral state was related to the vocalization rate (also known as cue rate) and time of day. When cue rate was higher, fin whales were more likely to swim slower and turn more than when cue rate was lower. During the night, fin whales were also more likely to swim slower and turn more than during the day. In addition, we examined whether the presence of singing fin whales was related to time and sea state using generalized additive models. Fin whale track presence was affected by day of the year and song season, and possibly also wind speed and wave height. Although the track kinematics from the fin whale tracks presented here are limited to a subset of whales that are acoustically active, they provide some of the only detailed movements of fin whales in the region and can be compared against fin whale swim speeds in other regions. Understanding how fin whale swimming behavior varies based on their vocalization patterns, time, and environmental factors will help us to contextualize potential changes in whale behavior during Navy training and testing on the range.

Habitat partitioning and the influence of benthic topography and oceanography on the distribution of fin and minke whales in the Bay of Fundy, Canada

2007 ◽  
Vol 87 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Simon N. Ingram ◽  
Laura Walshe ◽  
Dave Johnston ◽  
Emer Rogan
Keyword(s):  
Linear Relationship ◽  
Linear Models ◽  
Generalized Additive Models ◽  
Bottom Topography ◽  
Distribution Patterns ◽  
Additive Models ◽  
Bay Of Fundy ◽  
Fin Whale ◽  
Minke Whales ◽  
Fin Whales

We collected data on the distribution of fin whales (Balaenoptera physalus) and minke whales (Balaenoptera acutorostrata) in the Bay of Fundy, Canada from a whale-watching vessel during commercial tours between July and September 2002. A single observer recorded the positions, species, numbers and surface activity of whales encountered during boat tours. We controlled for biased search effort by calculating sightings rates for both species in cells measuring 2′ latitude by 2′ longitude throughout the study area. Sightings rates were calculated by dividing the number of sightings of fin and minke whales in each cell by the number of visits by the tour boat to that cell. We used generalized additive models and generalized linear models to examine the influence of benthic topography on whale distribution patterns. Models showed a non-linear relationship for minke whale sighting rates with increasing benthic slopes and a linear relationship for minke and fin whale sightings rates with increasing water depth. Sightings of minkes were concentrated in areas subject to tidal wakes near the northern tips of Grand Manan and Campobello Island. Fin whales were also found off the northern tip of Grand Manan but sighting rates for this species were highest in areas with less benthic sloping topography adjacent to the relatively deep Owen Basin. Foraging was recorded during 87% of all whale encounters and our results indicate that whale distribution in this area is likely to be influenced by depth, bottom topography and fine scale oceanographic features that facilitate foraging.

Statistical modelling reveals spatial, temporal, and environmental preferences for white sharks at an oceanic aggregation site

2020 ◽  
Vol 655 ◽  
pp. 171-183
Author(s):  
EE Becerril-García ◽  
RO Martínez-Rincón ◽  
F Galván-Magaña ◽  
O Santana-Morales ◽  
EM Hoyos-Padilla
Keyword(s):  
Feeding Habits ◽  
Generalized Additive Models ◽  
Statistical Modelling ◽  
Time Of Day ◽  
White Shark ◽  
Additive Models ◽  
Environmental Preferences ◽  
Data Set ◽  
Aggregation Site ◽  
Guadalupe Island

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.

scholarly journals Seasonal and diel cycles of fin whale acoustic occurrence near Elephant Island, Antarctica

2021 ◽  
Vol 8 (5) ◽  
pp. 201142 ◽  
Author(s):  
Elke Burkhardt ◽  
Ilse Van Opzeeland ◽  
Boris Cisewski ◽  
Ramona Mattmüller ◽  
Marlene Meister ◽  
...  
Keyword(s):  
Visual Information ◽  
Marine Protected Area ◽  
Annual Life Cycle ◽  
Sea Ice Concentration ◽  
Fin Whale ◽  
Diel Cycles ◽  
Ice Concentration ◽  
Fin Whales ◽  
Passive Acoustic ◽  
Elephant Island

This study investigates the relevance of the Elephant Island (EI) region for Southern Hemisphere fin whales ( Balaenoptera physalus ) in their annual life cycle. We collected 3 years of passive acoustic recordings (January 2013 to February 2016) northwest of EI to calculate time series of fin whale acoustic indices, daily acoustic occurrence, spectrograms, as well as the abundance of their 20 Hz pulses. Acoustic backscatter strength, sea ice concentration and chlorophyll-a composites provided concurrent environmental information for graphic comparisons. Acoustic interannual, seasonal and diel patterns together with visual information and literature resources were used to define the period of occupancy and to infer potential drivers for their behaviour. Spectral results suggest that these fin whales migrate annually to and from offshore central Chile. Acoustic data and visual information reveal their arrival at EI in December to feed without producing their typical 20 Hz pulse. For all 3 years, acoustic activity commences in February, peaks in May and decreases in August, in phase with the onset of their breeding season. Our results emphasize the importance of EI for fin whales throughout most of the year. Our recommendation is to consider EI for establishing a marine protected area to expedite the recovery of this vulnerable species.

scholarly journals Failure to estimate reliable sex ratios of guanaco from road-survey data

2009 ◽  
Vol 87 (10) ◽  
pp. 886-894 ◽  
Author(s):  
Julieta Pedrana ◽  
Alejandro Rodríguez ◽  
Javier Bustamante ◽  
Alejandro Travaini ◽  
Juan I. Zanón Martínez
Keyword(s):  
Sex Ratio ◽  
Null Hypothesis ◽  
Generalized Additive Models ◽  
Sex Ratios ◽  
Time Of Day ◽  
Additive Models ◽  
Family Group ◽  
Juvenile Abundance ◽  
Adult Sex Ratio ◽  
Parsimonious Model

The guanaco ( Lama guanicoe (Müller, 1776)) is a monomorphic polygynous mammal whose adult sex ratio is expected to be balanced or biased towards females. Remarkably male-biased sex ratios of adult guanacos are often estimated from road surveys. We analyzed the distribution of guanaco social groups recorded during road surveys in Patagonia, Argentina, to test the hypothesis that group assignation based upon behavioral traits is not unequivocal and can be biased by survey factors. Guanacos are organized into three social units (family groups, male groups, and solitary males) that are identified by their grouping behaviour. We recorded 992 guanaco groups, and estimated an adult sex ratio of 3.2 males/female. We used generalized additive models to test the null hypothesis that the probability of recording a group as a family group was constant. Alternatively, this probability could decrease when juvenile abundance and (or) detectability was low. The most parsimonious model showed that the probability of classifying a “family” group increased with date, and decreased with group size, distance to the observer, and time of day. Our results do not support the null hypothesis and suggest that road surveys are unsuitable to estimate reliably the social structure or sex ratio of guanaco populations.

Spatiotemporal distribution of foraging in a marine predator: behavioural drivers of hotspot formation

2020 ◽  
Vol 635 ◽  
pp. 187-202
Author(s):  
T Brough ◽  
W Rayment ◽  
E Slooten ◽  
S Dawson
Keyword(s):  
Time Of Day ◽  
Spatiotemporal Distribution ◽  
Temporal Effects ◽  
Marine Predator ◽  
Marine Predators ◽  
Additive Mixed Models ◽  
Density Analysis ◽  
The Times ◽  
Passive Acoustic ◽  
Spatial Locations

Many species of marine predators display defined hotspots in their distribution, although the reasons why this happens are not well understood in some species. Understanding whether hotspots are used for certain behaviours provides insights into the importance of these areas for the predators’ ecology and population viability. In this study, we investigated the spatiotemporal distribution of foraging behaviour in Hector’s dolphin Cephalorhynchus hectori, a small, endangered species from New Zealand. Passive acoustic monitoring of foraging ‘buzzes’ was carried out at 4 hotspots and 6 lower-use, ‘reference areas’, chosen randomly based on a previous density analysis of visual sightings. The distribution of buzzes was modelled among spatial locations and on 3 temporal scales (season, time of day, tidal state) with generalised additive mixed models using 82000 h of monitoring data. Foraging rates were significantly influenced by all 3 temporal effects, with substantial variation in the importance and nature of each effect among locations. The complexity of the temporal effects on foraging is likely due to the patchy nature of prey distributions and shows how foraging is highly variable at fine scales. Foraging rates were highest at the hotspots, suggesting that feeding opportunities shape fine-scale distribution in Hector’s dolphin. Foraging can be disrupted by anthropogenic influences. Thus, information from this study can be used to manage threats to this vital behaviour in the locations and at the times where it is most prevalent.

scholarly journals Predicting Malaria Transmission Dynamics in Dangassa, Mali: A Novel Approach Using Functional Generalized Additive Models

2020 ◽  
Vol 17 (17) ◽  
pp. 6339
Author(s):  
François Freddy Ateba ◽  
Manuel Febrero-Bande ◽  
Issaka Sagara ◽  
Nafomon Sogoba ◽  
Mahamoudou Touré ◽  
...  
Keyword(s):  
Wind Speed ◽  
Malaria Incidence ◽  
Generalized Additive Models ◽  
Community Health Center ◽  
Additive Model ◽  
Additive Models ◽  
Functional Regression ◽  
Novel Approach ◽  
Malaria Incidence Rate ◽  
Mean Wind Speed

Mali aims to reach the pre-elimination stage of malaria by the next decade. This study used functional regression models to predict the incidence of malaria as a function of past meteorological patterns to better prevent and to act proactively against impending malaria outbreaks. All data were collected over a five-year period (2012–2017) from 1400 persons who sought treatment at Dangassa’s community health center. Rainfall, temperature, humidity, and wind speed variables were collected. Functional Generalized Spectral Additive Model (FGSAM), Functional Generalized Linear Model (FGLM), and Functional Generalized Kernel Additive Model (FGKAM) were used to predict malaria incidence as a function of the pattern of meteorological indicators over a continuum of the 18 weeks preceding the week of interest. Their respective outcomes were compared in terms of predictive abilities. The results showed that (1) the highest malaria incidence rate occurred in the village 10 to 12 weeks after we observed a pattern of air humidity levels >65%, combined with two or more consecutive rain episodes and a mean wind speed <1.8 m/s; (2) among the three models, the FGLM obtained the best results in terms of prediction; and (3) FGSAM was shown to be a good compromise between FGLM and FGKAM in terms of flexibility and simplicity. The models showed that some meteorological conditions may provide a basis for detection of future outbreaks of malaria. The models developed in this paper are useful for implementing preventive strategies using past meteorological and past malaria incidence.

The Relationship between Mobility and COVID-19 in Germany: Modeling Case Occurrence using Apple's Mobility Trends Data

2021 ◽  
Author(s):  
Mark David Walker ◽  
Mihály Sulyok
Keyword(s):  
Generalized Additive Models ◽  
Information Criterion ◽  
Additive Models ◽  
Online Data ◽  
German Government ◽  
Explanatory Variables ◽  
Mobility Data ◽  
Community Mobility ◽  
The Relationship ◽  
Potential Use

Abstract Background Restrictions on social interaction and movement were implemented by the German government in March 2020 to reduce the transmission of coronavirus disease 2019 (COVID-19). Apple's “Mobility Trends” (AMT) data details levels of community mobility; it is a novel resource of potential use to epidemiologists. Objective The aim of the study is to use AMT data to examine the relationship between mobility and COVID-19 case occurrence for Germany. Is a change in mobility apparent following COVID-19 and the implementation of social restrictions? Is there a relationship between mobility and COVID-19 occurrence in Germany? Methods AMT data illustrates mobility levels throughout the epidemic, allowing the relationship between mobility and disease to be examined. Generalized additive models (GAMs) were established for Germany, with mobility categories, and date, as explanatory variables, and case numbers as response. Results Clear reductions in mobility occurred following the implementation of movement restrictions. There was a negative correlation between mobility and confirmed case numbers. GAM using all three categories of mobility data accounted for case occurrence as well and was favorable (AIC or Akaike Information Criterion: 2504) to models using categories separately (AIC with “driving,” 2511. “transit,” 2513. “walking,” 2508). Conclusion These results suggest an association between mobility and case occurrence. Further examination of the relationship between movement restrictions and COVID-19 transmission may be pertinent. The study shows how new sources of online data can be used to investigate problems in epidemiology.

scholarly journals Comparing Charlson and Elixhauser comorbidity indices with different weightings to predict in-hospital mortality: an analysis of national inpatient data

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Narayan Sharma ◽  
René Schwendimann ◽  
Olga Endrich ◽  
Dietmar Ausserhofer ◽  
Michael Simon
Keyword(s):  
Hospital Mortality ◽  
Patient Population ◽  
Generalized Additive Models ◽  
Routine Data ◽  
Predictive Performance ◽  
Population Based ◽  
Mortality Prediction ◽  
Additive Models ◽  
General Hospitals ◽  
Net Reclassification Improvement

Abstract Background Understanding how comorbidity measures contribute to patient mortality is essential both to describe patient health status and to adjust for risks and potential confounding. The Charlson and Elixhauser comorbidity indices are well-established for risk adjustment and mortality prediction. Still, a different set of comorbidity weights might improve the prediction of in-hospital mortality. The present study, therefore, aimed to derive a set of new Swiss Elixhauser comorbidity weightings, to validate and compare them against those of the Charlson and Elixhauser-based van Walraven weights in an adult in-patient population-based cohort of general hospitals. Methods Retrospective analysis was conducted with routine data of 102 Swiss general hospitals (2012–2017) for 6.09 million inpatient cases. To derive the Swiss weightings for the Elixhauser comorbidity index, we randomly halved the inpatient data and validated the results of part 1 alongside the established weighting systems in part 2, to predict in-hospital mortality. Charlson and van Walraven weights were applied to Charlson and Elixhauser comorbidity indices. Derivation and validation of weightings were conducted with generalized additive models adjusted for age, gender and hospital types. Results Overall, the Elixhauser indices, c-statistic with Swiss weights (0.867, 95% CI, 0.865–0.868) and van Walraven’s weights (0.863, 95% CI, 0.862–0.864) had substantial advantage over Charlson’s weights (0.850, 95% CI, 0.849–0.851) and in the derivation and validation groups. The net reclassification improvement of new Swiss weights improved the predictive performance by 1.6% on the Elixhauser-van Walraven and 4.9% on the Charlson weights. Conclusions All weightings confirmed previous results with the national dataset. The new Swiss weightings model improved slightly the prediction of in-hospital mortality in Swiss hospitals. The newly derive weights support patient population-based analysis of in-hospital mortality and seek country or specific cohort-based weightings.

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