Identifying spatial and temporal tradeoff of fish early life stages in the Gulf of Alaska and Bering Sea regions

As marine fish experience climate-driven changes in the ocean, one mode of adaptation is for fish to spatially and/or temporally shift the occupancy of their habitats. Spawning location (geography) and timing (phenology) are key traits that can affect not only survival, but also assessment and management of commercially harvested species. Phenology and geography of fish during early life stages have rarely been considered together, in spite of being linked in their outcome on fitness. We hypothesize a trade-off, with species that are constrained in space being less constrained in time, and vice-versa. Since the 1970s, the Alaska Fisheries Science Center EcoFOCI (Ecosystem and Fisheries-Oceanography Coordinated Investigations) group has conducted some of the most comprehensive ichthyoplankton surveys in the USA, presenting a timely opportunity to conduct retrospective and synthesis work. To this end, we have developed analytical models to: 1. quantify the degree to which fish spawning and larval geography and phenology in the Bering Sea and Gulf of Alaska are sensitive to changes in environmental conditions, and for a subset of 5-10 well sampled species, 2. Test whether there is a relationship between temporal and spatial variability during spawning and larval stages. The methodology assumes that spatio-temporal configurations that are consistently repeated over time (e.g., during spawning, or larval dispersal phases) are indicative of strong constraints, while those that are significantly and strongly linked to local changes in water temperature, are indicative of high spatio-temporal variability. Through this analysis we build capacity to study species adaptability to climate change utilizing analytical approaches that can account for potential bottlenecks affecting spatial and temporal distribution of a species during early life stages. Knowledge about these boundary responses is key for predicting the impact of future environmental change, such as ocean warming.