FishOtlilithPhysio - Fish Otolith Physiology, and Implications for Climate Change, Conservation, and Fisheries Management

Otoliths are calcium carbonate structures biomineralized in the inner ear of fish, and are used for balance and hearing. Otoliths grow continuously throughout the fish's life, forming continuous rings that can be aged much like trees. Today, fishery managers count otolith rings to estimate age, which is then incorporated into age-structured models to estimate wild fish populations. Fishery managers then use these otolith-reliant models to set catch limits to sustainably regulate fisheries and prevent overfishing. Many scientists also analyze the isotopic and elemental signatures of otoliths to gather historical environmental and metabolic factors such as temperature, diet, and salinity as experienced by the fish. Thus, the otolith is an invaluable tool for ecology, migratory biology, conservation, paleobiology, and fishery research. Despite its importance, our mechanistic understanding of otolith biomineralization remains poor. Furthermore, climate change will affect otoliths: ocean warming and acidification accelerate biomineralization, while hypoxia reduces it. This lack of mechanistic knowledge threatens the accuracy of otolith-reliant models, and by extension fisheries
management under future climate change. Thus, there is an urgent need to develop foundational understanding on how the inner ear biomineralizes the otolith, its annual rings, and its elemental signatures. This proposal brings together Drs. Garfield Kwan, Rod Wilson, and Clive Trueman (secondment), who collectively have the world-leading expertise and state-of-the-art facilities in fish physiology, inner ear cell biology, and biogeochemistry necessary to investigate the ion-transport pathways responsible for otolith responses to warming, acidification, hypoxia, and feeding. This knowledge is critical to understanding how fish otoliths respond to future climate scenarios, and safeguard modern otolith-reliant tools, coastal economies, fisheries, and food security for communities around the world.