Speaker: Emily Slesinger, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA

Topic:

Arctic cod reproduction under prolonged exposure to ocean acidification

High latitude ecosystems are vulnerable to ocean acidification (OA), potentially affecting important fish species including Arctic cod (Boreogadus saida), a key forage fish species in the Arctic Ocean important for birds, marine mammals and other commercial and subsistence fished species. As the effects of climate change continue to alter natural ecosystems, existing relationships between fish reproductive development, output and success may change due to the direct and indirect effects of environmental stressors on reproductive biology. Field-based methods can provide valuable information about the past and current status of fish populations, yet lack the control to define mechanistic links between environmental stressors, parental condition and reproduction, especially in harsh, remote environments. To fill this knowledge gap, we performed a 6-month experiment in the lab where we exposed adult Arctic cod to either control or OA conditions from the onset of reproductive development in early October through larval hatching at the end of March. We assessed adult energetic status post-spawning, female and male gamete quality, 24-hr post fertilization developmental success and condition, larval hatching success, hatch timing, and larval sizes and energy stores at hatch. Overall, we found that prolonged exposure to OA led to unique responses that differed between male and female fish, as well as across multiple life stages from adults to gametes to hatched larvae. This comprehensive experiment also produced useful data that allowed us to investigate other biological influences on Arctic cod reproduction (e.g., higher female energetic status leads to better embryo development!). In this seminar we will first discuss the effects of OA on Arctic cod reproduction and larval development, and then explore some of the additional biological influences on Arctic cod reproductive biology.