Biology subjects

Wright, P. J.

Publications and source records attributed to Wright, P. J..

5 recordsLinked to original sources

bioRxiv2025

Changing food conditions and size declines in a North Sea forage fish

Declining body sizes are prevalent in marine fish. While these declines have been suggested to be a response to increasing temperatures, the evidence is mixed and the underlying causes of observed declines often unknown. Here, we explore drivers of spatio-temporal patterns in size in lesser sandeel (Ammodytes marinus), an important prey for seabirds and marine mammals, focusing on ongoing size declines in the North Sea. We combine experimental and field data with ecological theory to develop a biologically realistic dynamic energy budget model that explicitly models feeding, metabolism and energy allocation to produce daily predictions of size during the juvenile growth season from 1979 to 2016. When forced with daily temperature estimates and zooplankton data from the Continuous Plankton Recorder, model predictions reproduce observed spatio-temporal patterns in size well. Our results suggest that the most plausible driver of observed size declines in the western North Sea is declining prey densities. In contrast, the direct effect of temperature on sandeel size is small, but interacts with local prey availability so that the effect varies in both size and direction over space. Our results thus suggest that to understand effects of climate change on fish size we need to account for both direct physiological effects and changes in resource availability. Finally, we use the model to show that early-life phenology and turbidity (via its impact on intake rates in the visually foraging sandeel) may also impact sandeel size, highlighting the importance of broadening our view of potential drivers of size declines.

ecology↗

bioRxiv2025

Animal tracking with particle algorithms for conservation

The movements of aquatic animals affect their exposure to threats and the efficacy of conservation measures, such as Marine Protected Areas (MPAs). However, many species movements remain poorly understood and difficult to reconstruct from available datasets, hampering conservation efforts. This is especially the case for species that rarely surface, for which data are often limited to observations from acoustic telemetry (detections) and ancillary sensors, such as archival tags. Here, we pioneer the use of state-of-the-art particle algorithms to model animal movement, integrate datasets and assess MPA design, using a case study of the Critically Endangered flapper skate (Dipturus intermedius) in Scotland. Our algorithms led to 5-fold improvements in maps of space use and 30-fold improvements in residency estimates (lower mean error) compared to prevailing heuristic methods. By formally integrating tracking datasets, we were uniquely able to examine movements beyond receivers into fished zones, MPA-scale residency and specific habitats beyond protected areas that may warrant protection. This work showcases a probabilistically sound modelling framework that is sufficiently fast, flexible and accessible to meet the demands of modern animal-tracking datasets in acoustic telemetry systems. This represents a marked advance for analyses of animal movements and MPA efficacy worldwide.

ecology↗

bioRxiv2022

MerMADE: Coupled biophysical, eco-evolutionary modelling for predicting population dynamics, movement and dispersal evolution in the marine environment

In order to understand patterns in species distributions, we need to understand the underlying mechanisms of dispersal, demography and evolutionary capability of these species. In the marine environment, few models combine these three key components likely due both to the computational challenges involved and the inherent challenges in data collection for parameterisation. To fill this gap, we have developed MerMADE, an individual-based, spatially explicit, eco-evolutionary coupled biophysical model for predicting population dynamics, dispersal and movement evolution in the marine environment (or aquatic environments in general). MerMADE combines dispersal in a 3D, hydrodynamically informed environment with population dynamics, demography and evolutionary functionality in order to investigate questions of connectivity, population persistence and evolution under environmental change and anthropogenic pressure. We illustrate its range of behavioural and physiological functionality using the lesser sandeel, Ammodytes marinus, as a case-study species in an invasion scenario. MerMADEs flexibility in species-specific parameterisation makes it a widely applicable, exciting tool in future sustainable management and conservation of aquatic species under environmental change.

ecology↗

bioRxiv2021

Rapid progression is associated with lymphoid follicle dysfunction in SIV-infected infant rhesus macaques

HIV-infected infants are at an increased risk of progressing rapidly to AIDS in the first weeks of life. Here, we evaluated immunological and virological parameters in 25 SIV-infected infant rhesus macaques to understand the factors influencing a rapid disease outcome. Infant macaques were infected with SIVmac251 and monitored for 10 to 17 weeks post-infection. SIV-infected infants were divided into either typical (TypP) or rapid (RP) progressor groups based on levels of plasma anti-SIV antibody levels and SIV plasma viral load (with RP infants having low SIV-specific antibodies and high viral loads). Following SIV infection, 11 out of 25 infant macaques exhibited an RP phenotype, with 5 of these succumbing to AIDS-related infections. Interestingly, the TypP and RP infants were similar in their CD4 depletion and activation of CD8 T cells as measured by the levels of HLA-DR on the cell surface. However, differences between the two groups were identified in other immune cell populations, including a failure to expand activated memory (CD21-CD27+) B cells in peripheral blood in RP infant macaques, as well as reduced levels of germinal center (GC) B cells and T follicular helper (Tfh) cells in spleens (4- and 10-weeks post-SIV). Reduced B cell proliferation in splenic germinal GCs was associated with increased SIV+ cell density and follicular type 1 interferon (IFN)-induced immune activation. Further analyses determined that at 2-weeks post SIV infection TypP infants exhibited elevated levels of the GC-inducing chemokine CXCL13 in plasma, as well as significantly lower levels of viral envelope diversity compared to RP infants. Our findings provide evidence that early viral and immunologic events following SIV infection contributes to impairment of B cells, Tfh cells and germinal center formation, ultimately impeding the development of SIV-specific antibody responses in rapidly progressing infant macaques.

immunology↗

bioRxiv2020

Linking scales of life-history variation with population structure in Atlantic cod

It is increasing recognised that sustainable exploitation of marine fish requires the consideration of population diversity and associated productivity. This study used a combination of genotypic screening and phenotypic traits to define the scale of population structuring in Atlantic cod inhabiting the northern North Sea (ICES 4a) and Scottish west coast (6a). The genetic analysis indicated an isolation by distance pattern with an even finer scale structuring than previously reported, that persisted over a decade and between feeding and spawning seasons. Spatial variation in phenotypic traits reflected genetic variation with cod maturing later and at a larger size near the Viking Bank in 4a. The identified population structuring provides an explanation for differences in historic changes in maturation schedules and the temperature exposure recorded in previous electronic tagging studies. The study also highlights how the mismatch between stock divisions and population units is leading to a misunderstanding about stock recovery.

ecology↗