Craig E Franklin

University of Queensland | UQ · School of Biological Sciences

Atlantic salmon are one of the most important fish species in global aquaculture production. However, temperature increases attributed to climatic events impair the production of Atlantic salmon during summer. Additionally, the nutritional requirements for this species when reared under elevated temperatures require elucidation. To address this gap...

Elevated ultraviolet radiation (UVR) is postulated as one of multiple, interrelated environmental stressors driving amphibian population declines globally. However, key knowledge gaps remain in elucidating the link between elevated UVR and amphibian declines in a changing climate, including whether timing and irradiance of UVR exposure in early lif...

An ectotherm’s performance and physiological function are strongly tied to environmental temperature, and many ectotherms thermoregulate behaviourally to reach optimum body temperatures. Tropical ectotherms are already living in environments matching their thermal tolerance range and may be expected to conform to environmental temperatures. We trac...

How animals move and associate with conspecifics is rarely random, with a population’s spatial structure forming the foundation on which the social behaviours of individuals form. Studies examining the spatial–social interface typically measure averaged behavioural differences between individuals; however, this neglects the inherent variation prese...

Ultraviolet radiation (UVR) is a pervasive factor that has shaped the evolution of life on Earth. Ambient levels of UVR mediate key biological functions but can also cause severe lethal and sublethal effects in a wide range of organisms. Furthermore, UVR is a powerful modulator of the effects of other environmental factors on organismal physiology,...

1) Ultraviolet radiation (UVR) has a range of strong effects on freshwater ecosystems, and changing UVR is implicated in global amphibian declines. The link between UVR and amphibian declines is not well understood, largely due to limited understanding of actual UVR exposure regimes in freshwater ecosystems. Logistical challenges in measuring aquat...

During summer, farmed Atlantic salmon (Salmo salar) can experience prolonged periods of warming and low aquatic oxygen levels due to climate change. This often results in a drop in feed intake; however, the physiological mechanism behind this behaviour is unclear. Digestion is a metabolically expensive process that can demand a high proportion of a...

Statistical analyses that physiologists use to test hypotheses predominantly centre around means, but the tail ends of the response distribution can behave quite differently and underpin important scientific phenomena. We demonstrated that quantile regression (QR) offers a way to bypass some limitations of least squares regression (LSR) by building...

Amphibian declines are sometimes correlated with increasing levels of ultraviolet radiation (UVR). While disease is often implicated in declines, environmental factors such as temperature and UVR play an important role in disease epidemiology. The mutagenic effects of UVR exposure on amphibians are worse at low temperatures. Amphibians from cold en...

To celebrate its centenary year, Journal of Experimental Biology (JEB) commissioned a collection of articles examining the past, present and future of experimental biology. This Commentary closes the collection by considering the important research opportunities and challenges that await us in the future. We expect that researchers will harness the...

1) Many amphibian declines are correlated with increasing levels of ultraviolet radiation (UVR). While disease is often implicated in declines, environmental factors such as temperature and UVR play an important role in disease epidemiology. 2) The mutagenic effects of UVR exposure on amphibians are worse at low temperatures. Amphibians from cold e...

Larvae randomly transferred to water baths 1.5 h acute 80 µW cm-2 UVB exposure Conclusions: Cold temperatures led to increased DNA damage in amphibian larvae. Cold acclimation compensated for effect of temperature on DNA damage. Chronic UV exposure did not result in 'UV-hardening'. Amphibians in cold environs may be more resilient to UV than realis...

Australian biodiversity is facing an extinction crisis; yet, government spending on conservation is wholly inadequate. The involvement of local communities in fundraising, direct actions, and habitat restoration is becoming vital in the fate of threatened species. Here, we review the research outputs and impact generated from 22 years of conservati...

1. Increases in ultraviolet radiation (UVR) correlate spatially and temporally with global amphibian population declines and interact with other stressors such as disease and temperature. Declines have largely occurred in high-altitude areas associated with greater UVR and cooler temperatures. 2. UVR is a powerful mutagenic harming organisms largel...

Ultraviolet radiation (UVR) from the sun is a natural daytime stressor for vertebrates in both terrestrial and aquatic ecosystems. UVR effects on the physiology of vertebrates manifest at the cellular level, but have bottom-up effects at the tissue level and on whole-animal performance and behaviours. Climate change and habitat loss (i.e. loss of s...

Ecological carryover effects, or delayed effects of the environment on an organism's phenotype, are central predictors of individual fitness and a key issue in conservation biology. Climate change imposes increasingly variable environmental conditions that may be challenging to early life-history stages in animals with complex life histories, leadi...

Animal social systems are inherently dynamic, with individuals moderating how they associate with conspecifics according to spatiotemporal shifts in population demography and resource availability. Understanding such variation is important not only to further our knowledge of a species' ecology but also to gain insights into the factors influencing...

In species where conflict is costly, individuals adopt alternative movement tactics to minimise the risk of competitive interactions. Dominant males often maintain defined territories, while less competitive males may be forced to adopt alternative tactics to maximise fitness and reduce conflict. However, the extent to which males switch tactics ac...

Given limited resources for wildlife conservation paired with an urgency to halt declines and rebuild populations, it is imperative that management actions are tactical and effective. Mechanisms are about how a system works and can inform threat identification and mitigation such that conservation actions that work can be identified. Here, we call...

Increasing drought frequency and duration pose a significant threat to fish species in dryland river systems. As ectotherms, fish thermal and hypoxia tolerances directly determine the capacity of species to persist in these environments during low flow periods when water temperatures are high and waterbodies become highly stratified. Chronic therma...

Anthropogenic ozone depletion has led to a 2-5% increase in ultraviolet B radiation (UVBR) levels reaching the earth's surface. Exposure to UVBR causes harmful DNA damage in amphibians, but this is minimized by DNA repair enzymes such as thermally sensitive cyclobutane pyrimidine dimer (CPD)-photolyase, with cool temperatures slowing repair rates....

Anthropogenic ozone depletion has led to a 2-5% increase in ultraviolet B radiation (UVBR) levels reaching the earth's surface. Exposure to UVBR causes harmful DNA damage in amphibians, but this is minimized by DNA repair enzymes such as thermally sensitive CPD-photolyase, with cool temperatures slowing repair rates. It is unknown whether amphibian...

Determining the contribution of elevated ultraviolet-B radiation (UVBR; 280 – 315 nm) to amphibian population declines is being hindered by a lack of knowledge about how different acute UVBR exposure regimes during early life history stages might affect post-metamorphic stages via long-term carryover effects. We acutely exposed tadpoles of the Aust...

Levels of ultraviolet (UV) radiation have increased in many parts of the world due to the anthropogenic destruction of the ozone layer. UV radiation is a potent immunosuppressant and can increase the susceptibility of animal hosts to pathogens. UV radiation can directly alter immune function via immunosuppression and photoimmunotolerance; however,...

Many aquatically respiring animals acutely exposed to low pH waters suffer inhibition of ion uptake, and loss of branchial (gill) epithelial integrity, culminating in a fatal loss of body Na+. Environmental calcium levels ([Ca2+]e) are pivotal in maintaining branchial junction integrity, with supplemental Ca2+ reversing the negative effects of low...

Many aquatically respiring animals inhabiting low pH waters can suffer acute inhibition of ion uptake and loss of branchial (gill) epithelial integrity, culminating in a fatal, rapid loss of body Na ⁺ . Environmental calcium levels ([Ca ²⁺ ] e ) are pivotal in maintaining branchial junction integrity, with supplemental Ca ²⁺ reversing the negative...

Cold water pollution (CWP) is caused by releases of unseasonably cold water from large, thermally stratified dams. Rapid and prolonged decreases in water temperature can have depressive effects on the metabolism, growth and swimming performance of fish. However, it is unknown if reducing the rate of temperature decrease could mitigate these negativ...

Climate and land-use changes are expected to increase the future occurrence of wildfires, with potentially devastating consequences for freshwater species and ecosystems. Wildfires that burn in close proximity to freshwater systems can significantly alter the physicochemical properties of water. Following wildfires and heavy rain, freshwater specie...

Report prepared for the Queensland Water Modelling Network, Department of Environment and Science, Queensland Government, Brisbane, Australia.

Determining the contribution of elevated ultraviolet-B radiation (UVBR; 280 – 315 nm) to amphibian population declines is being hindered by a lack of knowledge about how different acute UVBR exposure regimes during early life history stages might affect post-metamorphic stages via long-term carryover effects. We acutely exposed tadpoles of the Aust...

Conservation and management of mobile marine species requires an understanding of how movement behaviour and space-use varies among individuals and populations, and how intraspecific differences influence exposure to anthropogenic threats. Because of their long-distance movements, broad distribution and long lifespan, whale sharks (Rhincodon typus)...

Examining the social behaviors of solitary species can be challenging due to the rarity in which interactions occur and the large and often inaccessible areas which these animals inhabit. As shared space-use is a prerequisite for the expression of social behaviors, we can gain insights into the social environments of solitary species by examining t...

Ecoimmunology is a rapidly developing field that explores how the environment shapes immune function, which in turn influences host–parasite relationships and disease outcomes. Host immune defence is a key fitness determinant because it underlies the capacity of animals to resist or tolerate potential infections. Importantly, immune function can be...

The optimisation of feed composition is fundamental to maximising fish growth efficiency and performance in sustainable aquaculture. Traditionally this has been achieved through altering the quantity, ratio or type of macronutrients in fish feeds (i.e., proteins, lipids, carbohydrates). Here, we present an alternative approach that centres on reduc...

Invasive species are generally characterised by broad environmental tolerances that allow them to successfully inhabit multiple ecosystems. Cane toads (Rhinella marina) are physiologically tolerant to a broad range of environmental conditions; however, it has been observed that they do not frequently reproduce in the Great Artesian Basin springs of...

Despite decades of research, the role of elevated solar ultraviolet-B radiation (UVBR; 280–315 nm) in shaping amphibian populations remains ambiguous. These difficulties stem partly from a poor understanding of which parameters of UVBR exposure - dose, irradiance, and time interval - determine UVBR exposure health risk, and the potentially erroneou...

Despite decades of research, the role of elevated solar ultraviolet-B radiation (UVBR; 280 – 315 nm) in shaping amphibian populations remains ambiguous. These difficulties stem partly from a poor understanding of which parameters of UVBR exposure - dose, intensity and time interval - determine UVBR exposure health risk, and the potentially erroneou...

Multiple environmental changes are thought to be contributing to the widespread decline of amphibians in montane regions, but interactions between drivers of decline are not well understood. It has been proposed previously that elevated ultraviolet-B radiation (UBVR) and low temperatures may interact in their negative effects on health, immune func...

In 1992, the Union of Concerned Scientists shared their ‘World Scientists’ Warning to Humanity’ with governmental leaders worldwide, calling for immediate action to halt the environmental degradation that threatens the systems that support life on Earth. A follow-up ‘Second Warning’ was released in 2017, with over 15 000 scientists as signatories,...

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundr...

Climate affects all aspects of biology. Physiological traits play a key role in mediating these effects, because they define the fundamental niche of each organism. Climate change is likely to shift environmental conditions away from physiological optima. The consequences for species are significant: they must alter their physiology through plastic...

Environmental change and biodiversity loss are but two of the complex challenges facing conservation practitioners and policy makers. Relevant and robust scientific knowledge is critical for providing decision-makers with the actionable evidence needed to inform conservation decisions. In the Anthropocene, science that leads to meaningful improveme...

Diving ectothermic vertebrates are an important component of many aquatic ecosystems, but the threat of climate warming is particularly salient to this group. Dive durations typically decrease as water temperatures rise; yet, we lack an understanding of whether this trend is apparent in all diving ectotherms and how this group will fare under clima...

The COVID-19 pandemic and associated public health measures have had unanticipated effects on ecosystems and biodiversity. Conservation physiology and its mechanistic underpinnings are well positioned to generate robust data to inform the extent to which the Anthropause has benefited biodiversity through alterations in disturbance-, pollution-and c...

The Cooloola sedgefrog (Litoria cooloolensis) is one of a number of frog species endemic to the coastal sandy lowlands of east Australia exhibiting remarkable tolerance to dilute waters of low pH (< pH 3.5). To investigate the physiological and morphological underpinnings of acid tolerance in L. cooloolensis larvae, we compared Na+ balance, uptake...

Aquatic hypoxic events are increasing in frequency and intensity as concentrations of nutrients, such as nitrate, continue to rise from human activities. Many fish species can alter their behavior and physiology to cope with drops in oxygen, but these compensatory strategies may be compromised under high levels of nitrate pollution. Hence, we inves...

Conservation physiology is a rapidly expanding, multi-disciplinary field that utilizes physiological tools, knowledge, and concepts to understand and solve conservation problems. Here we provide a consolidated overview of the scope and goals of conservation physiology, with a focus on animals. We outline the major avenues by which conservation phys...

We discuss 12 themes that emerged from the set of case studies comprising the text, namely: (1) mechanisms matter for conservation; (2) physiology is just one source of knowledge; (3) physiology and behaviour are intertwined; (4) new tools and technologies should be embraced; (5) physiology can be valuable in captive settings; (6) conservation phys...

Globally, freshwater fish numbers have declined substantially in part due to anthropogenic structures (e.g. dams) that impede fish movements. The environmental and societal benefits of balancing environmental health with human resource requirements have meant that there is increasingly a concerted effort to remove or remediate barriers to fish pass...

Conservation physiology is a rapidly expanding, multi-disciplinary field that uses physiological tools to characterize and solve conservation problems. This text provides a consolidated overview of the scope, purpose, and goals of conservation physiology, with a focus on animals. It outlines the major avenues by which conservation physiology is con...

Inadequately designed culverts can be physical barriers to fish passage if they increase the velocity of water flow in the environment, alter natural turbulence patterns or fail to provide adequate water depth. They may also act as behavioural barriers to fish passage if they affect the willingness of fish species to enter or pass through the struc...

Exposure to nitrate is toxic to aquatic animals due to the formation of methaemoglobin and a subsequent loss of blood-oxygen carrying capacity. Yet, nitrate toxicity can be modulated by other stressors in the environment, such as elevated temperatures. Acclimation to elevated temperatures has been shown to offset the negative effects of nitrate on...

Ectotherms are predicted to show a reduction in absolute aerobic scope (AAS = maximum − standard metabolic rates) if habitat temperatures surpass optima. However, thermal phenotypic plasticity may play a protective role in the maintenance of AAS. In fishes, resting physiological rates (“physiological floors,” e.g., standard metabolic rates [SMR]) a...

Using depth sensor transmitters and an array of acoustic receivers to monitor the facultative air-breathing Australian lungfish (Neoceratodus forsteri), we investigated habitat preferences and behavioral responses to seasonal hypoxic zones in a riverine impoundment. Threedimensional (3-D) kernel utilisation distribution (KUD) models revealed that d...

Understanding how fish traverse man-made barriers (e.g. road-crossings and culverts) ensures that engineering and design guidelines achieve positive outcomes for fish communities. Water velocity, depth and fish body size are interrelated factors that influence fish passage through culverts. Velocity barriers have been a major focus of culvert remed...

Tropical rivers and estuaries are highly dynamic environments, where environmental conditions change dramatically over spatial and temporal scales. This creates both physiological and ecological challenges for euryhaline elasmobranchs, where fluctuations in salinity can impact not only osmoregulatory function but also the ability to find and acquir...

Rising temperatures are set to imperil freshwater fishes as climate change ensues unless compensatory strategies are employed. However, the presence of additional stressors, such as elevated nitrate concentrations, may affect the efficacy of compensatory responses. Here, juvenile silver perch (Bidyanus bidyanus) were exposed to current-day summer t...

Glycogen is a critical store for locomotion. Depleted glycogen stores are associated with increased fatigue during exercise. The reduced effectiveness of low-carbohydrate diets for weight loss over longer time periods may arise because such diets reduce glycogen stores and thereby physical activity energy expenditure. To explore the effect of a low...

Applying physiological tools, knowledge and concepts to understand conservation problems (i.e. conservation physiology) has become commonplace and confers an ability to understand mechanistic processes, develop predictive models and identify cause-and-effect relationships. Conservation physiology is making contributions to conservation solutions; t...