The Anthropometry of Forest Machine Operators in the Southern USA

Anthropometric dimensions critical to the design of operator workspaces and cab access in grapple skidders were collected from a sample of Southern United States loggers. The data were then compared to existing SAE and ILO anthropometric recommendations and data. Results indicated that southern grapple skidder operators are generally taller in stature, sitting height and seated eye height than the worldwide population measured to determine the SAE and ILO guides. Southern operators are also heavier than subjects measured for the SAE recommendations

Dead tired: evaluating the physiological status and survival of neonatal reef sharks under stress

Marine protected areas (MPAs) can protect shark populations from targeted fisheries, but resident shark populations may remain exposed to stressors like capture as bycatch and environmental change. Populations of young sharks that rely on shallow coastal habitats, e.g. as nursery areas, may be at risk of experiencing these stressors. The purpose of this study was to characterize various components of the physiological stress response of neonatal reef sharks following exposure to an exhaustive challenge under relevant environmental conditions. To accomplish this, we monitored markers of the secondary stress response and measured oxygen uptake rates (⁠ṀO2⁠) to compare to laboratory-derived baseline values in neonatal blacktip reef (Carcharhinus melanopterus) and sicklefin lemon sharks (Negaprion acutidens). Measurements occurred over three hours following exposure to an exhaustive challenge (gill-net capture with air exposure). Blood lactate concentrations and pH deviated from baseline values at the 3-h sample, indicating that both species were still stressed 3 h after capture. Evidence of a temperature effect on physiological status of either species was equivocal over 28–31°C. However, aspects of the physiological response were species-specific; N. acutidens exhibited a larger difference in blood pH relative to baseline values than C. melanopterus, possibly owing to higher minimum ṀO2⁠. Neither species experienced immediate mortality during the exhaustive challenge; although, single instances of delayed mortality were documented for each species. Energetic costs and recovery times could be extrapolated for C. melanopterus via respirometry; sharks were estimated to expend 9.9 kJ kg−1 (15% of energy expended on daily swimming) for a single challenge and could require 8.4 h to recover. These data suggest that neonatal C. melanopterus and N. acutidens are resilient to brief gill-net capture durations, but this was under a narrow temperature range. Defining species' vulnerability to stressors is important for understanding the efficacy of shark conservation tools, including MPAs

Analysing tropical elasmobranch blood samples in the field: blood stability during storage and validation of the HemoCue (R) haemoglobin analyser

Blood samples collected from wild-caught fishes can provide important information regarding the effects of capture (and thus post-release survival) as well as other stressors. Unfortunately, blood samples often cannot be analysed immediately upon sampling, and blood parameters (e.g. blood oxygen levels and acid-base parameters) are known to change with storage duration due to the metabolic activity of the red blood cells. We obtained blood samples from both untreated and stressed individuals of both blacktip reef shark (Carcharhinus melanopterus) and sicklefin lemon shark (Negaprion acutidens) to determine the effects of storage duration on blood pH, haematocrit and haemoglobin concentration ([Hb]). We found no significant effects after storage on ice for up to 180 minutes. Moreover, to validate the usability of a HemoCue haemoglobin analyser (a point-of-care device), we compared data from this device to [Hb] determined using the cyanomethaemoglobin method with blood samples from 10 individuals from each of the aforementioned species as well as epaulette shark (Hemiscyllium ocellatum). Values from the HemoCue consistently overestimated [Hb], and we therefore developed the necessary correction equations. The correction equations were not statistically different among the three elasmobranch species within the biologically relevant range but did differ from published corrections developed using blood from temperate teleost fishes. Although the HemoCue is useful in field situations, development of species-specific calibration equations may be necessary to ensure the reliability of inter-species comparisons of blood [Hb]. Together, these data should increase confidence in haematological stress indicators in elasmobranch fishes, measurements of which are critical for understanding the impact of anthropogenic stressors on these ecologically important species

Same species, different prerequisites: investigating body condition and foraging success in young reef sharks between an atoll and an island system

Acquiring and storing energy is vital to sharks of all age-classes. Viviparous shark embryos receive endogenous maternal energy reserves to sustain the first weeks after birth. Then, in order to maintain body condition, sharks must start foraging. Our goal was to understand whether maternal energy investments vary between blacktip reef sharks (Carcharhinus melanopterus) from two populations and to what extent body condition and the initiation of foraging might be affected by presumably variable maternal investments. A total of 546 young sharks were captured at St. Joseph atoll (Seychelles) and Moorea (French Polynesia) between 2014 and 2018, and indices of body condition and percentage of stomachs containing prey were measured. Maternal investment was found to be site-specific, with significantly larger, heavier, and better conditioned individuals in Moorea. Despite these advantages, as time progressed, Moorea sharks exhibited significant decreases in body condition and were slower to initiate foraging. We suggest that the young sharks’ foraging success is independent of the quality of maternal energy resources, and that other factors, such as prey availability, prey quality, and/or anthropogenic stressors are likely responsible for the observed differences across sites. Insights into intraspecific variations in early life-stages may further support site-specific management strategies for young sharks from nearshore habitats

The power struggle: assessing interacting global change stressors via experimental studies on sharks

Ocean warming and acidification act concurrently on marine ectotherms with the potential for detrimental, synergistic effects; yet, effects of these stressors remain understudied in large predatory fishes, including sharks. We tested for behavioural and physiological responses of blacktip reef shark (Carcharhinus melanopterus) neonates to climate change relevant changes in temperature (28 and 31 °C) and carbon dioxide partial pressures (pCO2; 650 and 1050 µatm) using a fully factorial design. Behavioural assays (lateralisation, activity level) were conducted upon 7–13 days of acclimation, and physiological assays (hypoxia tolerance, oxygen uptake rates, acid–base and haematological status) were conducted upon 14–17 days of acclimation. Haematocrit was higher in sharks acclimated to 31 °C than to 28 °C. Significant treatment effects were also detected for blood lactate and minimum oxygen uptake rate; although, these observations were not supported by adequate statistical power. Inter-individual variability was considerable for all measured traits, except for haematocrit. Moving forward, studies on similarly ‘hard-to-study’ species may account for large inter-individual variability by increasing replication, testing larger, yet ecologically relevant, differences in temperature and pCO2, and reducing measurement error. Robust experimental studies on elasmobranchs are critical to meaningfully assess the threat of global change stressors in these data-deficient species

Thermal acclimation of tropical coral reef fishes to global heat waves

As climate-driven heat waves become more frequent and intense, there is increasing urgency to understand how thermally sensitive species are responding. Acute heating events lasting days to months may elicit acclimation responses to improve performance and survival. However, the coordination of acclimation responses remains largely unknown for most stenothermal species. We documented the chronology of 18 metabolic and cardiorespiratory changes that occur in the gills, blood, spleen, and muscles when tropical coral reef fishes are thermally stressed (+3.0°C above ambient). Using representative coral reef fishes (Caesio cuning and Cheilodipterus quinquelineatus) separated by >100 million years of evolution and with stark differences in major life-history characteristics (i.e. lifespan, habitat use, mobility, etc.), we show that exposure duration illicited coordinated responses in 13 tissue and organ systems over 5 weeks. The onset and duration of biomarker responses differed between species, with C. cuning – an active, mobile species – initiating acclimation responses to unavoidable thermal stress within the first week of heat exposure; conversely, C. quinquelineatus – a sessile, territorial species – exhibited comparatively reduced acclimation responses that were delayed through time. Seven biomarkers, including red muscle citrate synthase and lactate dehydrogenase activities, blood glucose and hemoglobin concentrations, spleen somatic index, and gill lamellar perimeter and width, proved critical in evaluating acclimation progression and completion, as these provided consistent evaluation of thermal responses across species

Validation of a portable, waterproof blood pH analyser for elasmobranchs

Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH values measured using a portable, waterproof pH meter (Hanna Instruments HI 99161) with blood pH values measured by an i- STAT system (CG4+ cartridges), which was previously validated for teleost and elasmobranch fishes, to gauge the accuracy of the pH meter in determining whole blood pH for the Cuban dogfish (Squalus cubensis) and lemon shark (Negaprion brevirostris). There was a significant linear relationship between values derived via the pH meter and the i- STAT for both species across a wide range of pH values and temperatures (Cuban dogfish: 6.8-7.1 pH 24-30 degrees C; lemon sharks: 7.0-7.45 pH 25-31 degrees C). The relative error in the pH meter's measurements was similar to +/- 2.7%. Using this device with appropriate correction factors and consideration of calibration temperatures can result in both a rapid and accurate assessment of whole blood pH, at least for the two elasmobranch species examined here. Additional species should be examined in the future across a wide range of temperatures to determine whether correction factors are universal

Investigating the roles of phonological and semantic memory in sentence recall

The mechanisms underlying short-term sentence recall have been the subject of recent investigations. While both semantic and phonological information have been found to play a role in sentence recall, this has been established using different paradigms in previous research. As a result, it is not clear whether the contributions of semantic and phonological information are equivalent subject only to specific experimental conditions. The present study used a common paradigm with equally plausible lures to systematically compare the roles of semantic and phonological information in short-term sentence recall. The lure intrusion paradigm was used with three different lures that were all equally plausible in the context of the sentence: semantic, onset, and rhyme. Further, no contextual cues were provided in the sentence to bias the participant. The findings indicate that there were significantly more semantic and onset intrusions compared to rhyme intrusions. This is interpreted in light of models incorporating lexical information during sentence production

Elevating the impact of conservation physiology by building a community devoted to excellence, transparency, ethics, integrity and mutual respect

[Extract] Ten years ago, the journal Conservation Physiology was launched jointly by the Society for Experimental Biology and Oxford University Press. Much has been accomplished since 2012 including publishing over 600 papers in the journal and helping to build a sense of place for aspiring and practicing conservation physiologists (Cooke et al., 2020). Yet, more work is needed to further elevate the impact of conservation physiology as a discipline and community. Here, we summarize what is needed to build and strengthen a community devoted to not only excellence, transparency, ethics, integrity and mutual respect, but also courage to tackle some of the overarching challenges humanity faces. As active voices in the conservation physiology community we hope that this paper will help shape the future of our discipline while also guiding the activities and priorities of the journal and editorial team. Since the term ‘conservation physiology’ was coined by Wikelski and Cooke (2006) it has emerged as an essential component of conservation science and practice. Conservation physiology is about the use of physiological tools, knowledge and concepts to understand and solve conservation problems across diverse taxa (Cooke et al., 2013). It is regarded as being particularly effective at understanding mechanisms, generating cause–effect relationships (e.g. threat X does Y to organism Z), creating predictive tools and testing conservation interventions (Cooke and O’Connor, 2010). Issues relevant to conservation physiology range from very local, focused on recovery of an imperilled population (Birnie-Gauvin et al., 2017), to global-scale issues such as tackling the UN Sustainable Development Goals (Cooke et al., 2020) and the climate crisis (Madliger et al., 2021c). The discipline is now supported by a conceptual framework (Coristine et al., 2014), a journal (https://academic.oup.com/conphys) and a reference book (Madliger et al. 2021a). There is also a growing community of researchers who engage in conservation physiology and even define themselves as conservation physiologists (Madliger et al., 2021b). Moreover, in conservation physiology there are success stories that demonstrate the potential of conservation physiology (Madliger et al., 2016)

Species-specific molecular responses of wild coral reef fishes during a marine heatwave

The marine heatwave of 2016 was one of the longest and hottest thermal anomalies recorded on the Great Barrier Reef, influencing multiple species of marine ectotherms, including coral reef fishes. There is a gap in our understanding of what the physiological consequences of heatwaves in wild fish populations are. Thus, in this study, we used liver transcriptomes to understand the molecular response of five species to the 2016 heatwave conditions. Gene expression was species specific, yet we detected overlap in functional responses associated with thermal stress previously reported in experimental setups. The molecular response was also influenced by the duration of exposure to elevated temperatures. This study highlights the importance of considering the effects of extreme warming events when evaluating the consequences of climate change on fish communities