Desvignes, ThomasCasimir, UlrickPostlethwait, JohnDixon, Griffin May2024-09-192024-09-192024-03-05https://hdl.handle.net/1794/3008050 pagesThe ocean surrounding Antarctica started to cool about 35 million years ago to reach freezing temperatures about 10-15 million years ago, which immensely impacted its fauna. Antarctic notothenioids adapted to these freezing temperatures but today face unprecedented challenges with projected climate-driven temperature increases. Temperature significantly influences the developmental rates of fish embryos, with higher temperatures accelerating development until a critical point is reached, causing deformities or mortality. The impact of temperature increases on Antarctic fish embryos, including the abundant bullhead notothen Notothenia coriiceps, remains unknown. Loss of adaptive traits, such as the inducible heat shock response, raises concerns for Antarctic fish in the context of global climate change. The hatching time of N. coriiceps and other Antarctic fishes, crucially linked to solar exposure and planktonic blooms, may shift earlier with rising temperatures, thus affecting the availability of essential food resources and potentially larval survival. Understanding the impact of temperature on N. coriiceps embryonic development is important for assessing their survival capacity in changing climates and contributes to broader insights into climate change effects on freezing ecosystems. This research addresses this knowledge gap, offering implications for ecosystem management policies, conservation, and broader scientific understanding of how organisms cope with environmental stressors in the Antarctic ecosystem. N. coriiceps embryos raised in heated conditions showed an increased developmental rate of about 44% compared to siblings raised at ambient temperature and hatched earlier. The temperature increase appeared to accelerate development uniformly at all stages and did not dramatically change the relative order of skeletal structure emergence in embryos. There was, however, a notable increase in the frequency of anatomical and skeletal malformations in heated embryos compared to ambient embryos, especially in the jaw and axial/caudal region. In addition, the measurement taken of the length from the snout to the anus (LS2N) was found to be a reliable parameter for comparison of the developmental stages across samples independent of age. If Antarctic water temperatures continue to rise at their current rate, N. coriiceps, among other Antarctic fish, will likely suffer immensely in their ability to survive and reproduce successfully.en-USclimate changeglobal warmingdevelopmentAntarctic fishwater temperatureThesis