Nearshore movement ecology of a medium-bodied shark, the creek whaler Carcharhinus fitzroyensis

Background: The movement and habitat use patterns of medium-bodied nearshore sharks are poorly understood. However, these species face some of the highest levels of exposure to anthropogenic development. The habitat and space use strategies species exhibit affect their role within communities and how they respond to environmental change. The present study used passive acoustic telemetry to evaluate the residency, space use, and habitat use patterns of the creek whaler Carcharhinus fitzroyensis in a nearshore embayment in Queensland, Australia. Results: Individuals were monitored for approximately 18 months. Half of the monitored population were highly resident to the bay. In contrast, several individuals spent less than 2 weeks in the bay, suggesting that broader movements may occur in a portion of the population. Size had no effect on residency. Activity space size varied between months and time of day but was also not affected by animal size. All C. fitzroyensis spent the majority of time in seagrass habitat (70%) and deep water (>5 m) mud substrate (20%). Shallow mudflat, sandy inshore, and reef habitats were rarely used (7%). Although the sample size of immature individuals was relatively small, results indicated immature and mature C. fitzroyensis shared space and habitats. Conclusions: Overall, C. fitzroyensis used a combination of nearshore movement patterns typically exhibited by small- and large-bodied species. The movement patterns exhibited by C. fitzroyensis suggest that this species has a moderately high degree of seagrass habitat specialisation. Seagrass habitat is typically highly productive and may be an important foraging habitat for this species. Given the consistent use of seagrass habitat, C. fitzroyensis are likely vulnerable to population decline as a result of seagrass habitat loss. Future research should continue to investigate the unique movements of medium-bodied sharks

Effective ecosystem monitoring requires a multi-scaled approach

Ecosystem monitoring is fundamental to our understanding of how ecosystem change is impacting our natural resources and is vital for developing evidence-based policy and management. However, the different types of ecosystem monitoring, along with their recommended applications, are often poorly understood and contentious. Varying definitions and strict adherence to a specific monitoring type can inhibit effective ecosystem monitoring, leading to poor program development, implementation and outcomes. In an effort to develop a more consistent and clear understanding of ecosystem monitoring programs, we here review the main types of monitoring and recommend the widespread adoption of three classifications of monitoring, namely, targeted, surveillance and landscape monitoring. Landscape monitoring is conducted over large areas, provides spatial data, and enables questions relating to where and when ecosystem change is occurring to be addressed. Surveillance monitoring uses standardised field methods to inform on what is changing in our environments and the direction and magnitude of that change, whilst targeted monitoring is designed around testable hypotheses over defined areas and is the best approach for determining the causes of ecosystem change. The classification system is flexible and can incorporate different interests, objectives, targets and characteristics as well as different spatial scales and temporal frequencies, while also providing valuable structure and consistency across distinct ecosystem monitoring programs. To support our argument, we examine the ability of each monitoring type to inform on six key types of questions that are routinely posed for ecosystem monitoring programs, such as where and when change is occurring, what is the magnitude of change, and how can the change be managed? As we demonstrate, each type of ecosystem monitoring has its own strengths and weaknesses, which should be carefully considered relative to the desired results. Using this scheme, scientists and land managers can design programs best suited to their needs. Finally, we assert that for our most serious environmental challenges, it is essential that we include information from each of these monitoring scales to inform on all facets of ecosystem change, and this is best achieved through close collaboration between the scales. With a renewed understanding of the importance of each monitoring type, along with greater commitment to monitor cooperatively, we will be well placed to address some of our greatest environmental challenges

Common Polymorphisms at the <i>CYP17A1 </i>Locus Associate With Steroid Phenotype:Support for Blood Pressure Genome-Wide Association Study Signals at This Locus

Genome-wide association studies implicate the CYP17A1 gene in human blood pressure regulation although the causative polymorphisms are as yet unknown. We sought to identify common polymorphisms likely to explain this association. We sequenced the CYP17A1 locus in 60 normotensive individuals and observed 24 previously identified single-nucleotide polymorphisms with minor allele frequency &gt;0.05. From these, we selected, for further studies, 7 polymorphisms located ≤2 kb upstream of the CYP17A1 transcription start site. In vitro reporter gene assays identified 3 of these (rs138009835, rs2150927, and rs2486758) as having significant functional effects. We then analyzed the association between the 7 polymorphisms and the urinary steroid metabolites in a hypertensive cohort (n=232). Significant associations included that of rs138009835 with aldosterone metabolite excretion; rs2150927 associated with the ratio of tetrahydrodeoxycorticosterone to tetrahydrodeoxycortisol, which we used as an index of 17α-hydroxylation. Linkage analysis showed rs138009835 to be the only 1 of the 7 polymorphisms in strong linkage disequilibrium with the blood pressure–associated polymorphisms identified in the previous studies. In conclusion, we have identified, characterized, and investigated common polymorphisms at the CYP17A1 locus that have functional effects on gene transcription in vitro and associate with corticosteroid phenotype in vivo. Of these, rs138009835—which we associate with changes in aldosterone level—is in strong linkage disequilibrium with polymorphisms linked by genome-wide association studies to blood pressure regulation. This finding clearly has implications for the development of high blood pressure in a large proportion of the population and justifies further investigation of rs138009835 and its effects

A global perspective on the trophic geography of sharks

Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.This research was conducted as part of C.S.B.’s Ph.D dissertation, which was funded by the University of Southampton and NERC (NE/L50161X/1), and through a NERC Grant-in-Kind from the Life Sciences Mass Spectrometry Facility (LSMSF; EK267-03/16). We thank A. Bates, D. Sims, F. Neat, R. McGill and J. Newton for their analytical contributions and comments on the manuscripts.Peer reviewe

Localization of type 1 diabetes susceptibility to the MHC class I genes HLA-B and HLA-A

The major histocompatibility complex (MHC) on chromosome 6 is associated with susceptibility to more common diseases than any other region of the human genome, including almost all disorders classified as autoimmune. In type 1 diabetes the major genetic susceptibility determinants have been mapped to the MHC class II genes HLA-DQB1 and HLA-DRB1 (refs 1-3), but these genes cannot completely explain the association between type 1 diabetes and the MHC region. Owing to the region's extreme gene density, the multiplicity of disease-associated alleles, strong associations between alleles, limited genotyping capability, and inadequate statistical approaches and sample sizes, which, and how many, loci within the MHC determine susceptibility remains unclear. Here, in several large type 1 diabetes data sets, we analyse a combined total of 1,729 polymorphisms, and apply statistical methods - recursive partitioning and regression - to pinpoint disease susceptibility to the MHC class I genes HLA-B and HLA-A (risk ratios >1.5; Pcombined = 2.01 × 10-19 and 2.35 × 10-13, respectively) in addition to the established associations of the MHC class II genes. Other loci with smaller and/or rarer effects might also be involved, but to find these, future searches must take into account both the HLA class II and class I genes and use even larger samples. Taken together with previous studies, we conclude that MHC-class-I-mediated events, principally involving HLA-B*39, contribute to the aetiology of type 1 diabetes. ©2007 Nature Publishing Group

Student Motivation and Online Learning: How do we do it?

For the first time in education history, school has been moved from a physical space to a virtual one. Due to the pandemic of COVID-19 and the mandated stay-at-home order, students were tied to learn from their homes. This caused a new foundation of online learning taught by the classroom teacher. In this new learning environment through very unprecedented times, there are undiscovered questions to the basic student learning concepts such as motivation and engagement. This teacher research delves into the search for possible solutions to motivating students in an online environment rather than the traditional physical school space. Motivation is defined in three parts; attendance, performance, and engagement. Attendance was the presence or absence of a student from the school day. Performance was the quality of the students’ work and representation of understanding. Lastly, engagement was participation and an active role in the learning environment or process. Motivation is a key concept to successful student learning and their educational experience. With a drastic -and unexpected- change in the educational format, this research provides critical data on how to motivate our students

Habitat and dietary selectivity of nearshore shark populations

The resource use strategies species exhibit affects their role within communities and how they respond to environmental change. Species that adopt generalist strategies are typically less vulnerable to environmental fluctuations than specialists. However, specialists often have lower energy costs and are more efficient at extracting and processing preferred resources. This dissertation defines shark ecological specialisation in order to evaluate the resource use patterns of nearshore sharks and discusses how shark resource use patterns can affect their vulnerability to environmental change. \ud \ud Sharks are traditionally classified as generalists that use a variety of habitats and prey. While this is an accurate description of some species, sharks exhibit a range of resource use strategies that includes highly selective or specialised behaviours. However, discussion on how to define the ecological specialisation of sharks has been limited. This dissertation presents a conceptual framework within which to define the specialisation of sharks that can be applied to different environmental scales. Shark species with varying degrees of specialisation are presented within the proposed context.\ud \ud Passive acoustic telemetry was used to examine the residency, space use, and habitat selection and specialisation patterns of the small-bodied Australian sharpnose shark, Rhizoprionodon taylori, and the medium-bodied creek whaler Carcharhinus fitzroyensis, in Cleveland Bay, Queensland, Australia. Stable isotope analysis of δ¹³C (¹³C/¹²C) and δ¹⁵N (¹⁵N/¹⁴N) was used to define the regional nearshore residency, movements, trophic level, and benthic and pelagic contributions to the diet of R. taylori. δ¹³C values vary at the base of the food chain but are conserved up the food chain. δ¹⁵N values increase in predictable quantities between trophic levels. Therefore, δ¹³C and δ¹⁵N values can be used to indicate the foraging location and diet of populations. Plasma and muscle δ¹³C and δ¹⁵N of R. taylori were collected from five embayments, including Cleveland Bay, on the northeast coast of Queensland.\ud \ud Results of the acoustic tracking showed the majority of R. taylori were present in Cleveland Bay for short periods of time, ranging from 1 to 112 days (mean ± SE = 17 ± 5). The majority of individuals were present in Cleveland Bay for less than two weeks. Low residency suggests that R. taylori home ranges likely span multiple bays. Individual monthly activity space ranged from 4.3 and 21.4 km² (mean ± SE =11.3 km² ± 0.90) for 50% kernel utilisation distributions (KUDs) and 21.5 and 80.4 km² (mean ± SE = 51.0 km² ± 3.9) for 95% KUDs. Space use analysis indicated R. taylori roamed widely throughout the bay, but monthly activity space size was consistent among individuals and over time. Sex and size had no influence on R. taylori residency or activity space size. Both the population and individuals occupied wide habitat niches which included seagrass, outer bay mud substrate, and sandy inshore habitat. However, both resident and transitory R. taylori consistently selected for seagrass over other habitats, potentially for feeding. Mudflat and reef habitats were generally avoided. Habitat selection appeared to be influenced by changes in freshwater input into Cleveland Bay. Selection for seagrass habitat, which is adjacent to large river mouths, decreased during periods of high river flow, suggesting R. taylori may have limited tolerance to low salinity.\ud \ud Stable isotope analysis showed that there was a positive correlation between R. taylori tissue and environmental (seagrass and plankton) δ¹³C values based on location. Shark populations with the highest tissue δ¹⁵N were collected from areas with the highest baseline δ¹⁵N values. Moreover, populations from bays that were > 100 km apart had distinct isotopic values. These results indicate R. taylori were not foraging more than 100 km from their capture location within 6 to 12 months. However, δ¹³C values of individuals in nearby bays (30-70 km apart) were indistinguishable, suggesting individuals foraged and moved between bays that were within 100 km of each other during a 6 to 12 month period. Therefore, isotope results were consistent with the low residency exhibited by R. taylori in Cleveland Bay. Isotope analysis also revealed R. taylori had a wide trophic range and consumed prey from benthic and pelagic sources. In all areas, benthic sources were important to the diet, suggesting benthic habitats (e.g. seagrass) may be important to R. taylori. However, there was geographic and temporal variation in R. taylori diet. These results indicate R. taylori has a broad dietary niche, but different populations may have unique effects on distinct areas. Variation in diet also suggests R. taylori may be adaptive to changes in prey availability.\ud \ud In contrast to R. taylori, most C. fitzroyensis were highly resident and present in Cleveland Bay for long periods of time, ranging 1 to 452 days (mean ± SE = 205 ± 53). However, a few individuals spent less than two weeks in the bay, suggesting broader movements occur in a portion of the population. Size and sex had no effect on presence. Individual monthly activity space ranged from 2.6 to 19.8 km² (mean ± SE =10.6 km² ± 0.3) for 50% KUDs and 9.1 to 81.9 km² (mean ± SE = 47.9 km² ± 1.0) for 95% KUDs. Activity space size varied between months and diel period but was not affected by animal size. Activity spaces in August were significantly smaller and concentrated closer to the shore than in other months. This simultaneous shift in space use by all individuals may have been to due biotic changes in the bay, such as changes in prey availability. Larger day time activity spaces suggest C. fitzroyensis may be primarily diurnal feeders. All resident C. fitzroyensis spent the majority of time in seagrass and to a lesser extent outer bay mud substrate habitat. Seagrass was consistently selected for throughout the monitoring period while use of outer bay mud substrate was highly irregular. Shallow mudflat, sandy inshore, and reef habitats were rarely used. There was no difference in space or habitat use between immature and mature individuals, indicating different age classes shared space and habitats. \ud \ud The results of acoustic and isotope analyses indicated that seagrass habitat is the preferred habitat of R. taylori and C. fitzroyensis. Seagrass is typically highly productive and may be an important foraging habitat for these species. For that reason, seagrass conservation will be an important consideration for the future spatial management of these species. However, R. taylori used different habitats and embayments and had a broad diet. Therefore, results indicate R. taylori has a low degree of resource specialisation and is probably adaptive to local environmental change. In contrast, the movement patterns exhibited by C. fitzroyensis suggest this species has a moderately high degree of habitat specialisation and is highly resident. Although diet information is not available for C. fitzroyensis, the movement patterns of C. fitzroyensis indicate this species will likely be more vulnerable to local environmental change, specifically a decline in seagrass abundance. By evaluating the resource use patterns of nearshore sharks, this dissertation has provided valuable information on the potential vulnerabilities of poorly understood shark species while also developing a conceptual framework for future resource specialisation investigations