DEEP TIME IN THE DEEP SEA: LESSONS FROM CONSERVATION PALEOBIOLOGY (Invited Presentation)

The deep sea is the world’s largest habitat by volume, yet the impacts of human activity, including fishing and climate change, on deep-sea ecosystems are poorly constrained. Apart from industrial whaling of the 1900s, the deep sea has mostly been spared from large-scale fishing activities. However as coastal resources are depleted, more attention and effort has been put into exploiting pelagic and deep-sea fish populations as resources for human consumption. Compared to their coastal counterparts, deep-sea fish generally have extended life histories, including slower time to maturity, lower reproductive rates, and longer lifespans. Due to this, commercially exploited deep-sea fish populations may be slower to replenish their biomass than coastal populations with increased fishing pressure. Further, the deep sea is less environmentally variable than coastal or surface waters, and so many deep sea inhabitants are particularly sensitive to even small changes in temperature and chemistry caused by anthropogenic greenhouse gas emissions. Understanding how deep-sea ecosystems may respond to major changes, both in environment and in biomass or population, is paramount to effectively conserving and managing this ecosystem. Here we investigate the impact of environmental and ecological change on deep-sea marine vertebrate communities, drawing on a series of case studies spanning the Cenozoic Era considering changes in speciation, extinction, community composition and biomass of fish and sharks in the deep sea. By taking this deep-time perspective, we are able to quantify historical variability as well as assess the impact of ecosystem response to a variety of types and magnitudes of environmental change. This helps to build a framework built on the principles of conservation paleobiology for protecting deep sea ecosystems and mitigating the impacts of anthropogenic global change.