Dungeness crabs are a foundation species, sustaining one of the Pacific Northwest’s most valuable fisheries and holding cultural importance to tribal communities. Yet, marine heatwaves during the reproductive season threaten reproduction success. In contrast, green crabs, listed by the International Union for Conservation of Nature (IUCN) among the world’s most invasive species, owes much of its spread to broad thermal tolerance, with population growth often spiking after periods of elevated sea-surface temperatures. While multiple studies report on physiological characteristics of green crabs during early life stages, the molecular basis causing this early-stage resilience, especially compared to the native Dungeness, remains largely unknown.

By integrating thermal thresholds with gene expression for both Dungeness and green crabs, Kandace’s project will identify the molecular markers that improve predictions of recruitment (the process of young individuals surviving to join the population) and inform risk metrics to guide management of fishery stock and invasion predictions during marine heatwaves. Focusing on early life stages, a key but understudied bottleneck for populations, this cross-species approach links molecular plasticity — the ability of cells to adapt to stress such as changing environmental conditions — to ecological performance.

The research team will collect female Dungeness and green crabs that are brooding (carrying fertilized eggs) from estuaries along the Oregon and Washington coasts. Once back at their lab, the team will expose the crabs to ecologically relevant temperature regimes that mimic current coastal conditions and marine heatwave conditions. Kandace will sample the crab embryos daily to measure their development, survival and physical traits. Using ecologically relevant temperature regimes will allow the research team to compare embryonic gene expression and physiological performance in Dungeness and green crabs to uncover the gene networks and regulatory pathways that determine thermal tolerance versus thermal sensitivity.

Kandace will compile these experimentally derived thermal risk thresholds and molecular biomarkers into a report with biomarkers that can be used to identify populations that are more vulnerable or resilient during extreme heat events. As a primary interest holder, The Washington Department of Fish and Wildlife will use these outputs to support climate-responsive management decisions, improving both recruitment forecasting of Dungeness and invasive species mitigation. These insights also have broader applications to other commercially and ecologically important coastal taxa facing rapid climate change.