Research
I am currently a science advisor for the Great Reef Census, one of the largest marine citizen science projects globally. My primary research involves developing methodology that combines citizen science, artificial intelligence, and modelling. The goal is to design the most accurate reporting possible to inform on-the-ground management.
I use a combination of modelling and empirical data collected through fieldwork and laboratory experiments. Throughout my PhD, I built bioenergetic models to understand how individuals, populations and species interact with their environment, and in turn how changing environmental and human-induced pressures affect the energetics of species of high fishery, economic or conservation value. Techniques used include respirometry, accelerometry, hydrodynamic modelling and other quantitative analysis using R programming.
I has been interviewed by Forbes magazine to discuss this research, and a full list Chris' scientific publications can be found on Google Scholar or Research Gate.
Published Work (select)
"Flexibility for fuelling reproduction in a pelagic ray (Mobula eregoodoo) suggested by bioenergetic modelling"
(Lawson et al., Journal of Fish Biology)
Here we investigated measurements of energy density and bioenergetic modelling for a pelagic ray, Mobula eregoodoo, to estimate its relative allocation to various bodily processes, and especially reproduction. The data revealed M. eregoodoo uses up to 21.0 and 2.5% of its annual energy budget on growth and reproduction, respectively. During pregnancy, females depleted energy reserves in the liver which, along with their biennial reproductive cycle, aligns with general theory that ectotherms are capital breeders, and thus build energy reserves prior to reproduction. However, the reduction in energy reserves did not account for all reproductive costs, and hence gravid females supplement reproductive costs through energy derived from the diet; as per an income breeding strategy. These characteristics imply M. eregoodoo exhibits some flexibility in fuelling reproduction depending on energy availability throughout the reproductive cycle, which may be prevalent in other elasmobranchs. The data represent the first estimates of both the metabolic costs of gestation in elasmobranchs, and the relative cost of reproduction in rays. Energy costs and plasticity associated with highly variable reproductive strategies in elasmobranchs may influence long-term population viability under a rapidly changing environment.
"Bioenergetic Model Sensitivity to Diet Diversity Across Space, Time and Ontogeny"
(Lawson et al., Frontiers in Marine Science)
[open access]
Consumption is the primary trophic interaction in ecosystems and its accurate estimation is required for reliable ecosystem modelling. When estimating consumption, species’ diets are commonly assumed to be the average of those that occur among habitats, seasons, and life stages which introduces uncertainty and error into consumption rate estimates. We present a case study of a teleost (Yellowfin Bream Acanthopagrus australis) that quantifies the potential error in consumption (in mass) and growth rate estimates when using diet data from different regions and times and ignoring ontogenetic variability. Ontogenetic diet trends were examined through gut content analysis (n=1130 fish) and incorporated into a bioenergetic model (the ‘primary’ model) that included diet variability (n=144 prey sources) and ontogenetic changes in metabolism (1 – 7 y) to estimate lifetime consumption. We quantified error by building nine model scenarios that each incorporated different spatiotemporal diet data of four published studies. The model scenarios produced individual lifetime consumption estimates that were between 25% lower and 15% higher than the primary model (maximum difference was 53%, range 11.7 kg to 17.8 kg). When consumption (in mass) was held constant, differences in diet quality among models caused a several-fold range in growth rate (0.04 – 1.07 g d-1). Our findings showcase the large uncertainty in consumption rate estimates due to diet diversity, and illustrate that caution is required when considering bioenergetic results among locations, times and ontogeny.
https://doi.org/10.3389/fmars.2021.625855
"Powering Ocean Giants: The Energetics of Shark and Ray Megafauna"
(Lawson et al. Trends in Ecology and Evolution)
Shark and ray megafauna have crucial roles as top predators in many marine ecosystems, but are currently among the most threatened vertebrates and, based on historical extinctions, may be highly susceptible to future environmental perturbations. However, our understanding of their energetics lags behind that of other taxa. Such knowledge is required to answer important ecological questions and predict their responses to ocean warming, which may be limited by expanding ocean deoxygenation and declining prey availability. To develop bioenergetics models for shark and ray megafauna, incremental improvements in respirometry systems are useful but unlikely to accommodate the largest species. Advances in biologging tools and modelling could help answer the most pressing ecological questions about these iconic species.
https://doi.org/10.1016/j.tree.2019.07.001