Understanding the impacts of foraging disruptions to odontocete body condition is fundamental to quantifying biological effects of human disturbance and environmental changes on cetacean populations. ...Here, reductions in body volume of free-ranging pygmy killer whales (Feresa attenuata) were calculated using repeated measurements of the same individuals obtained through Unoccupied Aerial System (UAS)-photogrammetry during a prolonged disruption in foraging activity arising from a 21-day stranding event. Stranded individuals were used to verify UAS-derived volume and length estimates through 3D-imaging, water displacement, and post-mortem measurements. We show that (a) UAS estimates of length were within 1.5% of actual body length and UAS volume estimates were within 10-13% of actual volume, (b) foraging disruption resulted in a daily decrease of 2% of total body mass/day, and (c) pygmy killer whales can lose up to 27% of their total body weight within 17 days. These findings highlight the use of UAS as a promising new method to remotely monitor changes in body condition and animal health, which can be used to determine the potential effects of anthropogenic disturbance and environmental change on free-ranging odontocetes.
The cost of reproduction is a key parameter determining a species’ life history strategy. Despite exhibiting some of the fastest offspring growth rates among mammals, the cost of reproduction in ...baleen whales is largely unknown since standard field metabolic techniques cannot be applied. We quantified the cost of reproduction for southern right whales Eubalaena australis over a 3 mo breeding season. We did this by determining the relationship between calf growth rate and maternal rate of loss in energy reserves, using repeated measurements of body volume obtained from un manned aerial vehicle photogrammetry. We recorded 1118 body volume estimates from 40 female and calf pairs over 40 to 89 d. Calves grew at a rate of 3.2 cm d−1 (SD = 0.45) in body length and 0.081 m³ d−1 (SD = 0.011) in body volume, while females decreased in volume at a rate of 0.126 m³ d−1 (SD = 0.036). The average volume conversion efficiency from female to calf was 68% (SD = 16.91). Calf growth rate was positively related to the rate of loss in maternal body volume, suggesting that maternal volume loss is proportional to the energy investment into her calf. Maternal in vestment was determined by her body size and condition, with longer and more rotund females investing more volume into their calves compared to shorter and leaner females. Lactating females lost on average 25% of their initial body volume over the 3 mo breeding season. This study demonstrates the considerable energetic cost that females face during the lactation period, and highlights the importance of sufficient maternal energy reserves for reproduction in this capital breeding species.
The eastern North Pacific gray whale
Eschrichtius robustus
experienced an unusual mortality event (UME) in 2019-2020, with 384 whales found dead along the Pacific coasts of Mexico, USA and Canada. A ...similar UME in 1999-2000 was speculated to have been caused by starvation, but body condition data were not available to test this hypothesis. Between 2017 and 2019, we used unmanned aerial vehicles (drones) and photogrammetry methods to measure the body condition of gray whales in San Ignacio Lagoon, Baja California Sur, Mexico. Body condition was calculated from the residual of the relationship between body volume and length. The body condition of gray whales was significantly lower in 2018 (-11.1%, SE = 1.74, n = 531) and 2019 (-9.7%, SE = 1.76, n = 628) compared to 2017 (n = 59) for all reproductive classes (calves, juveniles, adults and lactating females). Overall, lactating females were in good body condition. The reduction in body condition of whales in 2018-2019 is unlikely to have affected their survival, but could have reduced their reproductive rate by prolonging the post-weaning recovery time. This could explain the low number of mother-calf pairs observed in the San Ignacio Lagoon in 2018 and 2019. For juveniles and adults that arrived in the lagoons with less energy reserves, their reduced body condition may have been close to their survival threshold. This could explain the high proportion of juveniles and adults among the stranded dead whales in 2019-2020. Although the underlying cause of the reduction in gray whale body condition is unknown, starvation likely contributed to the 2019-2020 UME.
Body mass is a fundamental feature of animal physiology. Although sperm whales (Physeter macrocephalus) are the largest toothed predators on earth, body mass is seldom included in studies of their ...ecophysiology and bioenergetics due to the inherent difficulties of obtaining direct measurements. We used UAV‐photogrammetry to estimate the weight of free‐ranging sperm whales. Aerial photographs (23 calves, 11 juveniles, 55 nonmother adults, 13 mothers) were collected in the Eastern Caribbean and Mediterranean Sea during 2017–2020. Body length, widths, and heights (dorso‐ventral distance at 5% increments) were measured from dorsal and lateral photographs, while body volume was calculated using an elliptical model. Volume varied noticeably (12.01 ± 4.79 m3) in larger animals (>8 m), indicating fluctuations in body condition of adults and mothers. Volume was converted to mass, using tissue‐density estimates from catch data, animal‐borne tags, and body‐tissue composition. Average total body density ranged from 834 to 1,003 kg/m3, while the weight predictions matched with existing measurements and weight‐length relationships. Our body‐mass models can be used to study sperm whale bioenergetics, including inter‐ and intraseasonal variations in body condition, somatic growth, metabolic rates, and cost of reproduction.
Shark‐based tourism is a rapidly growing industry, particularly with whale sharks, as new hotspots are identified worldwide. Understanding any impacts of tourism is essential to minimize any ...potential detrimental effects on the target species and habitat.
In‐water behavioural observations of whale sharks were used to understand any impacts of tourism at a small site in Panaon Island, Southern Leyte, Philippines. A generalized linear mixed model was fitted to test anthropogenic and environmental variables, with interaction duration as the response variable, to assess any disturbance to the animals by the tourism activities.
Whale sharks were observed between the months of November and June between 2013 and 2016, with highly variable seasons. In total, 527 tourist‐whale shark interactions were recorded during 359 trips identifying 104 individual whale sharks, most of which were juvenile males (85%, measuring c. 5.5 m total length). Proximity of motorized vessels and interactions in deeper waters were found to significantly shorten interactions. Short‐term behavioural changes were observed in response to human events (e.g. touching). Interactions when whale sharks were feeding were significantly longer than when they were not. Individual behavioural variability was observed.
Impacts could be mitigated with small managerial changes and increased enforcement, such as limiting the number of motorized vessels and the number of people around the whale sharks. Although no long‐term impacts were recorded during this study, it is difficult to ascertain this in a long‐lived, wide‐ranging species.
This knowledge gap highlights the need to build long‐term monitoring programmes, and to apply the precautionary principle for the sustainable use of this endangered species.
The sensory mechanisms used by baleen whales (Mysticeti) for locating ephemeral, dense prey patches in vast marine habitats are poorly understood. Baleen whales have a functional olfactory system ...with paired rather than single blowholes (nares), potentially enabling stereo-olfaction. Dimethyl sulfide (DMS) is an odorous gas emitted by phytoplankton in response to grazing by zooplankton. Some seabirds use DMS to locate prey, but this ability has not been demonstrated in whales. For 14 extant species of baleen whale, nares morphometrics (imagery from unoccupied aerial systems, UAS) was related to published trophic level indices using Bayesian phylogenetic mixed modelling. A significant negative relationship was found between nares width and whale trophic level (
= -0.08, lower 95% CI = -0.13, upper 95% CI = -0.03), corresponding with a 39% increase in nares width from highest to lowest trophic level. Thus, species with nasal morphology best suited to stereo-olfaction are more zooplanktivorous. These findings provide evidence that some baleen whale species may be able to localize odorants e.g. DMS. Our results help direct future behavioural trials of olfaction in baleen whales, by highlighting the most appropriate species to study. This is a research priority, given the potential for DMS-mediated plastic ingestion by whales.
Understanding the population health status of long‐lived and slow‐reproducing species is critical for their management. However, it can take decades with traditional monitoring techniques to detect ...population‐level changes in demographic parameters. Early detection of the effects of environmental and anthropogenic stressors on vital rates would aid in forecasting changes in population dynamics and therefore inform management efforts. Changes in vital rates strongly correlate with deviations in population growth, highlighting the need for novel approaches that can provide early warning signs of population decline (e.g., changes in age structure). We tested a novel and frequentist approach, using Unoccupied Aerial System (UAS) photogrammetry, to assess the population age structure of small delphinids. First, we measured the precision and accuracy of UAS photogrammetry in estimating total body length (TL) of trained bottlenose dolphins (Tursiops truncatus). Using a log‐transformed linear model, we estimated TL using the blowhole to dorsal fin distance (BHDF) for surfacing animals. To test the performance of UAS photogrammetry to age‐classify individuals, we then used length measurements from a 35‐year dataset from a free‐ranging bottlenose dolphin community to simulate UAS estimates of BHDF and TL. We tested five age classifiers and determined where young individuals (<10 years) were assigned when misclassified. Finally, we tested whether UAS‐simulated BHDF only or the associated TL estimates provided better classifications. TL of surfacing dolphins was overestimated by 3.3% ±3.1% based on UAS‐estimated BHDF. Our age classifiers performed best in predicting age‐class when using broader and fewer (two and three) age‐class bins with ~80% and ~72% assignment performance, respectively. Overall, 72.5%–93% of the individuals were correctly classified within 2 years of their actual age‐class bin. Similar classification performances were obtained using both proxies. UAS photogrammetry is a non‐invasive, inexpensive, and effective method to estimate TL and age‐class of free‐swimming dolphins. UAS photogrammetry can facilitate the detection of early signs of population changes, which can provide important insights for timely management decisions.
Here, we use Unoccupied Aerial System (UAS) photogrammetry to develop a length‐based method of estimating the age‐class of free‐ranging delphinids. First, we measure the accuracy and precision of UAS photogrammetry in estimating the total body length (TL) and the distance between the blowhole and the dorsal fin insertion (BHDF) of trained bottlenose dolphins (Tursiops truncatus). Then, we test the performance of UAS photogrammetry in estimating the age‐class (based on TL and BHDF) of free‐ranging bottlenose dolphins. Our findings suggest that UAS photogrammetry is an effective method to estimate TL and age‐class of free‐swimming dolphins. This method can facilitate the detection of early signs of population changes, which can provide important insights for timely management decisions. Right photograph taken under research permit NOAA‐PIFSC 21476.
Cette thèse se constitue de deux analyses statistiques qui sont mises au service de l’étude de l’identité culturelle de Saint-Julien de Brioude. Riche d’un luxuriant passé, la compagnie de Brioude ...entretenait un réseau de relations complexes. Les arts et la liturgie ont constitué notre support pour l’étude identitaire du chapitre. L’étude du bréviaire brivadois nous a permis de montrer l’originalité de la liturgie brivadoise. Cette liturgie n’était pas aussi clermontoise qu’on le présumait jusqu’à présent. Née d’un métissage mêlant la tradition liturgique aquitaine et vellave, la liturgie de Brioude avait été dotée de pièces de chants et d’oraisons propres. La mise en scène spatiale des reliques participait à la typicité de la collégiale que les pèlerins visitaient. À côté du tombeau de Julien, d’autres corps de saints et des reliques faisaient l’objet de dévotions. Le programme sculpté de la collégiale avait été pensé en deux temps. Souvent fidèlement liés aux sujets iconographiques utilisés dans le diocèse de Clermont, les chapiteaux de Brioude avaient été agencés en fonction des zones divisant l’espace ecclésial. Ces zones gigognes se voisinaient en faisant concurrencer l’agencement des reliques, du mobilier et des images. Le chevet faisait dialoguer l’iconographie du Saint-Sépulcre et des croisades avec le tombeau-reliquaire de Julien et les autels secondaires. Les sculptures étaient utilisées comme de véritables signalétiques s’animant autour du drame liturgique. Les images participaient à la constitution d’un espace mémoriel participant à la mémorisation liturgique de l’histoire.Cette étude offre des perspectives dépassant le cadre de la monographie. Liturgie et arts peuvent fournir des éléments de compréhension concrets à propos des échanges culturels et des aménagements de l’espace ecclésial. L’origine familiale des chanoines avait déterminée cette zone (le Brivadois) située à la confluence de l’Aquitaine auvergnate et du Velay (zone tampon avec l’Empire). Le chapitre de Brioude placé au milieu des deux, sans être central, en avait tiré les bénéfices culturels et un rayonnement propre. Le chapitre de Brioude avait ainsi pu façonner sa collégiale afin de célébrer la compagnie canoniale elle-même et le saint dont elle détenait les reliques. Attirer à elle les foules permettait à la compagnie aussi bien de faire perdurer la mémoire du saint patron que de leur procurer les ressources essentielles à leur fonctionnement. La collégiale était réalisée comme un marqueur du paysage déterminant une identité architecturale attractive.
This thesis is made up of two statistical analyses which are at the service of the study of Saint-Julien de Brioude’s cultural identity. Having had a lush history, the Brioude Company kept a complex web of relationships. Both, art and liturgy, were the frame for the identity study of this chapter. The study of the Brivadois breviary proved how unique the Brivadois liturgy was. Unlike what was thought at first, such liturgy was not as close as to that of Clermont-Ferrand. Born from the blending of liturgical tradition from Aquitaine and Velay, the Brivadois liturgy was endowed with singing pieces and specific orations. The spatial staging of the relics partook of the collegiate’s specificity the pilgrims visited. Next to Julien’s gravestone, other Saints’ bodies and relics were subjected to devotions.The collegiate’s sculpted program was designed in two times. As they were often faithfully linked with the iconographic subjects used in Clermont’s diocese, Brioude’s capitals were put together in accordance with the areas dividing the ecclesial space. These nested areas were next to one another and highlighted the differences between the relics, the furniture and the images. The chevet intertwined Saint-Sépulcre’s iconography, along with its Crusades, with Julien’s reliquary gravestone and the secondary altars. The sculptures were used as genuine signage livened up around the liturgical tragedy. The images took part in the setting up of history’s liturgical memorial space.This study gives new perspectives which go beyond the monographic frame. Liturgy and arts can provide us with tangible understanding elements regarding the cultural exchanges and the layout of the ecclesial space. The canon’s familial origin determined this area (the Brivadois) located at the confluence of Auvergne’s Aquitaine and the Velay (buffer zone with the Empire). From the Brioude chapter located between these two, without being central, it extracted the cultural benefits as well as a very own standing. The Brioude chapter thus managed to shape its collegiate so as to celebrate the canonical company itself and the Saint whom she possessed the relics from. Attracting the crowd enabled the company to carry own the patron Saint’s memory and to provide themselves with the essential resources to make it operate. The collegiate was undertaken as a landscape’s landmark determining an attractive architectural identity.
The French Revolution undertook to rationalize the right of ownership by including it in land ownership. However, the country's situation forces us to tolerate uses that form the basis of the ...relationship with the land. The definition of a new tax system, with the tax registry as a reference, encourages the valuation of the owner of the land, which the censal suffrage benefits until 1848. However, from Corsica to the North, from Brittany to Alsace, from the Pyrenees to the Ardennes, living environments present specificities that are difficult to satisfy the desires of promoters of private land rights. Until the 1960s, this conflictual relationship was the matrix for the definition of farming.
La Révolution entreprend de rationaliser le droit de propriété en l’inscrivant dans la possession du sol. Pourtant, la situation du pays oblige à tolérer des usages qui fondent le rapport aux terres. La définition d’une nouvelle fiscalité, avec pour référence le cadastre fiscal, pousse à valoriser le propriétaire du sol, que le suffrage censitaire avantage jusqu’en 1848. Or, de la Corse au Nord, de la Bretagne à l’Alsace, des Pyrénées aux Ardennes, les cadres de vie présentent des spécificités difficiles à plier aux désirs des promoteurs d’un droit foncier privatif. Jusque dans les années 1960, cette relation conflictuelle est la matrice de la définition de l’exploitation agricole.
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