Distribution and habitat use modelling from satellite tracking data of humpback whales in Brazil agree with shipboard survey data modelling

Funding: The Monitoring Whales by Satellite Project (Projeto Monitoramento de Baleias por Satélite, PMBS) research cruises were sponsored by Shell Brasil. The Federal University of Rio Grande (FURG) and the R/V Atlântico Sul crew provided essential support during fieldwork. G.A.B.’s PhD work is funded by the Brazilian National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq; Science Without Borders, scholarship number 208203/2014-1).Statistical modelling of animal distributions has been widely applied to explain how mobile species use their habitats. The distribution of and habitat use by humpback whales Megaptera novaeangliae off the eastern coast of Brazil have previously been investigated by modelling visual survey data. Here, we modelled distribution in their breeding range using individual tracking data to compare ecological inferences with those from previous models from line transect data. A generalised estimating equation framework was used to model the tracking data and pseudo-absences as functions of spatial covariates. Covariates considered were latitude and longitude, sea surface temperature (SST), current and wind speeds near the surface, distances to shelf-break and the coast, sea bottom depth and slope, and a factor variable representing ‘shelter’. Two modelling exercises were developed: a habitat use model (HUM) and a distribution model (DIM). Covariates retained in the selected HUM were SST, distance to coast and shelf-break, current and wind speeds and shelter. Covariates retained in the selected DIM were latitude/longitude, current speed and distances to shelf-break and coast. The modelled relationships between whale occurrence and environmental covariates using tracking data were similar to those using line transect data. Distribution maps were also similar, supporting higher densities around the Abrolhos Archipelago and to its south. We showed that habitat use and distribution of this population in the area could be similarly inferred by modelling either line transect or tracking data. Using these 2 approaches in conjunction can strengthen the understanding of important ecological aspects of animal populations.PostprintPeer reviewe

Acute Aerobic Exercise Reduces 24-H Ambulatory Blood Pressure Levels in Long-Term-Treated Hypertensive Patients

BACKGROUND: Even with anti-hypertensive therapy, it is difficult to maintain optimal systemic blood pressure values in hypertensive patients. Exercise may reduce blood pressure in untreated hypertensive, but its effect when combined with long-term anti-hypertensive therapy remains unclear. Our purpose was to evaluate the acute effects of a single session of aerobic exercise on the blood pressure of long-term-treated hypertensive patients. METHODS: Fifty treated hypertensive patients (18/32 male/female; 46.5±8.2 years; Body mass index: 27.8±4.7 kg/m²) were monitored for 24 h with respect to ambulatory (A) blood pressure after an aerobic exercise session (post-exercise) and a control period (control) in random order. Aerobic exercise consisted of 40 minutes on a cycle-ergometer, with the mean exercise intensity at 60% of the patient's reserve heart rate. RESULTS: Post-exercise ambulatory blood pressure was reduced for 24 h systolic (126±8.6 vs. 123.1±8.7 mmHg, p=0.004) and diastolic blood pressure (81.9±8 vs. 79.8±8.5 mmHg, p=0.004), daytime diastolic blood pressure (85.5±8.5 vs. 83.9±8.8 mmHg, p=0.04), and nighttime S (116.8±9.9 vs. 112.5±9.2 mmHg, p<0.001) and diastolic blood pressure (73.5±8.8 vs. 70.1±8.4 mmHg, p<0.001). Post-exercise daytime systolic blood pressure also tended to be reduced (129.8±9.3 vs. 127.8±9.4 mmHg, p=0.06). These post-exercise decreases in ambulatory blood pressure increased the percentage of patients displaying normal 24h systolic blood pressure (58% vs. 76%, p=0.007), daytime systolic blood pressure (68% vs. 82%, p=0.02), and nighttime diastolic blood pressure (56% vs. 72%, p=0.02). Nighttime systolic blood pressure also tended to increase (58% vs. 80%, p=0.058). CONCLUSION: A single bout of aerobic exercise reduced 24h ambulatory blood pressure levels in long-term-treated hypertensive patients and increased the percentage of patients reaching normal ambulatory blood pressure values. These effects suggest that aerobic exercise may have a potential role in blood pressure management of long-term-treated hypertensive

Humpback whale Megaptera novaeangliae (Cetartiodactyla: Balaenopteridae) group sizes in line transect ship surveys : an evaluation of observer errors

Accurate estimates of group sizes through line transect sampling methods are important to correctly ascertain the abundance of animals that occur in groups. Since the average observed group size is a component of the distance sampling formula, bias in these data leads to biased abundance estimates. This study aimed to evaluate the potential errors in group size estimation during line transect ship surveys to estimate abundances of the humpback whale, Megaptera novaeangliae (Borowski 1781). In a research cruise along the Brazilian coast, an experiment to collect group size information was conducted from two different sighting platforms on the same vessel. Group sizes were recorded by primary observers at first sighting (PO1) and, in some cases, after some time (PO2). A tracker (T) was located on a higher platform to estimate the sizes of groups detected by the primary observers, but tracked one group at a time until it passed abeam. Thus, the dedicated effort to obtain multiple group counts (i.e. higher platform, more time and no responsibility for detecting new groups) was expected to provide more accurate numbers. PO2 estimates were compared with PO1 estimates, and T estimates were compared with both PO1 and PO2. Additionally, ratios between T and both PO2 (R1) and PO1 (R2), and between PO2 and PO1 (R3) were calculated. To investigate a possible improvement in abundance estimates, a correction factor (CF) was computed from the ratio of T and PO2 means. Primary observer self-correction (= 1.60, CV% = 70.3) was statistically similar to the correction for the tracker (= 1.62, CV% = 84.1). CF resulted in 1 and would not improve abundance estimates. This study supports that observers conducting line transect surveys on large whales have the potential to provide group size information that is as adequate as the correction procedure adopted.Publisher PDFPeer reviewe

Acute aerobic exercise reduces 24-h ambulatory blood pressure levels in long-term-treated hypertensive patients

BACKGROUND: Even with anti-hypertensive therapy, it is difficult to maintain optimal systemic blood pressure values in hypertensive patients. Exercise may reduce blood pressure in untreated hypertensive, but its effect when combined with long-term anti-hypertensive therapy remains unclear. Our purpose was to evaluate the acute effects of a single session of aerobic exercise on the blood pressure of long-term-treated hypertensive patients. METHODS: Fifty treated hypertensive patients (18/32 male/female; 46.5±8.2 years; Body mass index: 27.8±4.7 kg/m²) were monitored for 24 h with respect to ambulatory (A) blood pressure after an aerobic exercise session (post-exercise) and a control period (control) in random order. Aerobic exercise consisted of 40 minutes on a cycle-ergometer, with the mean exercise intensity at 60% of the patient's reserve heart rate. RESULTS: Post-exercise ambulatory blood pressure was reduced for 24 h systolic (126±8.6 vs. 123.1±8.7 mmHg, p=0.004) and diastolic blood pressure (81.9±8 vs. 79.8±8.5 mmHg, p=0.004), daytime diastolic blood pressure (85.5±8.5 vs. 83.9±8.8 mmHg, p=0.04), and nighttime S (116.8±9.9 vs. 112.5±9.2 mmHg,

Wintertime polynya structure and variability from thermal remote sensing and seal-borne observations at Pine Island Glacier, West Antarctica

Funding: This work was enabled by the NSF-NERC International Thwaites Glacier Collaboration: Thwaites-Amundsen Regional Survey and Network (ITGC: TARSAN; NERC Grant: NE/S006419/1, NE/S006591/1, NSF Grant: 1738992) and the NERC Ice Sheet Stability Programme (iSTAR; NERC Grant: NE/J005703/1).Antarctica’s ice shelves play a critical role in modulating ice loss to the ocean by buttressing grounded ice upstream. With the potential to impact ice-shelf stability, persistent polynyas (open-water areas surrounded by sea ice, persisting for multiple years at the same location) at the edge of many ice-shelf fronts, are maintained by winds and/or ocean heat, and are locations of strong ice-ocean-atmosphere interactions. However, in situ observations of polynyas are sparse due to the logistical constraints of collecting Antarctic field measurements. Here, we used wintertime (May–August) temperature and salinity observations derived from seal-borne tags deployed in 2014, 2019, and 2020, in conjunction with thermal imagery from the MODerate resolution Imaging Spectroradiometer (MODIS) and the Landsat 8 Thermal Infrared Sensor (TIRS) to investigate the spatial, temporal, and thermal structural variability of polynyas near Pine Island Glacier (PIG). Across the three winters considered, there were 148 anomalously warm (>3σ from background) seal dives near the PIG ice front, including 24 dives that coincided with MODIS images with minimal cloud cover that also showed a warm surface temperature anomaly. These warm surface temperatures correlated with ocean temperatures down to 150 m depth or deeper, depending on the year, suggesting that MODISderived surface thermal anomalies can be used for monitoring polynya presence and structure during polar night. The finer spatial resolution (100 m) of TIRS wintertime thermal imagery captures more detailed thermal structural variability within these polynyas, which may provide year-round insight into sub-ice-shelf processes if this dataset is collected operationally.Publisher PDFPeer reviewe

First record of sharksucker Echeneis naucrates (Perciformes, Echeneidae) associated to a young Guiana dolphin Sotalia guianensis (Cetartiodactyla, Delphinidae) in north-eastern Brazil

Funding: Conselho Nacional de Desenvolvimento Científico e Tecnológico - 208203/2014-1.Suckerfish attached to dolphin species have been extensively reported worldwide, yet such association has been rarely seen in the tropical and shallow waters of South America. In Brazil, the Guiana dolphin Sotalia guianensis is distributed along almost the entire coastal extension and only one case of association with suckerfish has been published. Here we report on a sharksucker Echeneis naucrates associated with a young Guiana dolphin for north-eastern coast of Brazil. The juvenile dolphin with an attached sharksucker was observed in two occasions separated by a 47-day period; we hypothesize the occurrence of host attachment fidelity. The present report adds information to better discuss the ecological interactions between echeneids and dolphins, and expands the baseline information on cetacean species serving as host to suckerfish.Publisher PDFPeer reviewe

Young humpback whale Megaptera novaeangliae feeding in Santa Catarina coastal waters, Southern Brazil, and a ship strike report

Background Humpback whales Megaptera novaeangliae are cosmopolitan and highly migratory animals that rarely feed in low latitude waters during their breeding seasons. The western South Atlantic humpback whale population breeds off the Brazilian coast, from Natal (4°S) to Cabo Frio (23°S) and migration to their feeding grounds is known to be undertaken through offshore waters. Results Here we report on an unusual stranding of a young humpback whale that was feeding in the coastal waters of Santa Catarina state (27°S), in October 2014. Evidence of a ship strike and that the animal had fed in no more than a few hours before death are also presented. Additionally, it is the first time that Peisos petrunkevitchi, a sergestid shrimp species, is described as prey for large whales. Conclusions Although more information is required before we can further discuss whether the area could provide an important source of food for young humpback whales, the present ship strike highlights a possibly important threat in case this ecological feature is confirmed in the future.Publisher PDFPeer reviewe

Anthropogenic impact on a pregnant Cuvier's beaked whale (Ziphius cavirostris) stranded in Brazil

Background: Because of their usually cryptic behaviour, most knowledge on the biology of beaked whales are from records of stranded animals. Although the Cuvier’s beaked whale (Ziphius cavirostris) is the best known species of the ziphiidae family, little information on its reproduction is available. Results: Here we report on the stranding of a dead pregnant female with clear signs of anthropogenic impact, including the presence of a fishing artefact in the stomach. Conclusions: The region of the stranding (north-eastern coast of Brazil) is an area of increasing interest for oil and gas exploitation. Conservation concerns may arise from findings such as the one presented and discussed here.Publisher PDFPeer reviewe

Whale, whale, everywhere: increasing abundance of western South Atlantic humpback whales (Megaptera novaeangliae) in their wintering grounds

The western South Atlantic (WSA) humpback whale population inhabits the coast of Brazil during the breeding and calving season in winter and spring. This population was depleted to near extinction by whaling in the mid-twentieth century. Despite recent signs of recovery, increasing coastal and offshore development pose potential threats to these animals. Therefore, continuous monitoring is needed to assess population status and support conservation strategies. The aim of this work was to present ship-based line-transect estimates of abundance for humpback whales in their WSA breeding ground and to investigate potential changes in population size. Two cruises surveyed the coast of Brazil during August-September in 2008 and 2012. The area surveyed in 2008 corresponded to the currently recognized population breeding area; effort in 2012 was limited due to unfavorable weather conditions. WSA humpback whale population size in 2008 was estimated at 16,410 (CV = 0.228, 95% CI = 10,563–25,495) animals. In order to compare abundance between 2008 and 2012, estimates for the area between Salvador and Cabo Frio, which were consistently covered in the two years, were computed at 15,332 (CV = 0.243, 95% CI = 9,595–24,500) and 19,429 (CV = 0.101, 95% CI = 15,958–23,654) whales, respectively. The difference in the two estimates represents an increase of 26.7% in whale numbers in a 4-year period. The estimated abundance for 2008 is considered the most robust for the WSA humpback whale population because the ship survey conducted in that year minimized bias from various sources. Results presented here indicate that in 2008, the WSA humpback whale population was at least around 60% of its estimated pre-modern whaling abundance and that it may recover to its pre-exploitation size sooner than previously estimated.Publisher PDFPeer reviewe

Ocean variability beneath Thwaites Eastern Ice Shelf driven by the Pine Island Bay Gyre strength

West Antarctic ice-shelf thinning is primarily caused by ocean-driven basal melting. Here we assess ocean variability below Thwaites Eastern Ice Shelf (TEIS) and reveal the importance of local ocean circulation and sea-ice. Measurements obtained from two sub-ice-shelf moorings, spanning January 2020 to March 2021, show warming of the ice-shelf cavity and an increase in meltwater fraction of the upper sub-ice layer. Combined with ocean modelling results, our observations suggest that meltwater from Pine Island Ice Shelf feeds into the TEIS cavity, adding to horizontal heat transport there. We propose that a weakening of the Pine Island Bay gyre caused by prolonged sea-ice cover from April 2020 to March 2021 allowed meltwater-enriched waters to enter the TEIS cavity, which increased the temperature of the upper layer. Our study highlights the sensitivity of ocean circulation beneath ice shelves to local atmosphere-sea-ice-ocean forcing in neighbouring open oceans