Larval Biogeography and Varying Spawning Behavior of Bering Sea Groundfishes: Implications for Management in a Changing Seascape

• Main Author: Vary, Laura
• Other Authors: Ciannelli, Lorenzo, Harte, Michael, Rogers, Lauren, College of Earth, Ocean, and Atmospheric Sciences
• Format: Master Thesis
• Language: English
• Published: Oregon State University
• Subjects: Bering Sea; Sea ice; Alaska
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/6969z808c

Early life stages of marine fishes exert substantial control on the productivity and resilience of marine fisheries, as these life stages represent periods of extreme mortality. Additionally, eggs and larvae of marine fishes respond rapidly to environmental change and can thus be used to infer ecosystem-wide responses to climate change or environmental regime shifts. In the Bering Sea (BS), considerable populations of fishes and shellfishes support huge fisheries of economic importance for Alaska and the United States. Groundfishes represent a considerable sector of this economy; in 2019, 83% of all harvest in Alaskan waters was for groundfishes and the ex-vessel value of groundfish fisheries comprised 50% of total Alaskan ex-vessel value. The BS is also a physically unique large marine ecosystem, with three hydrographic domains that represent annually consistent vertical patterns in temperature and salinity. Tidal processes, atmospheric forcing, coastal currents and the annual cycle of sea ice formation and breakup impart nutrients into the region, thus supporting the considerable populations of marine micro- and macro-organisms. Currently, fisheries in the BS are managed sustainably; Alaska leads the country in ecosystem-based fisheries management and has done so for decades. However, climate change is exerting sweeping impacts on the BS, transitioning typical interannual variability in sea surface temperature and other physical dynamics to multi-year periods of warm or cold regimes. Such warm regimes are expected to modify the distribution and phenology of reproduction in marine fishes. These two dimensions, though, have not been analyzed in conjunction with one another which has led to a lack of clarity on whether certain species are more likely to modify their reproductive geography or phenology. Furthermore, early life stage preferences of water masses, defined by temperature and salinity, are not mapped for many larval groundfishes at the species level. As early life stages are quick responders to ...