Ecology Of Larval Fishes Along The Western Antarctic Peninsula: Climate-Change Impact, Taxonomy, Phenology, And Thermal Tolerance

• Main Author: Corso, Andrew Derik
• Format: Text
• Language: English
• Published: W&M ScholarWorks 2023
• Subjects: Ecology and Evolutionary Biology; Antarctic; Antarctic Peninsula; Southern Ocean; The Antarctic; Antarc*; Antarctic Krill; Antarctica; Sea ice
• Online Access: https://scholarworks.wm.edu/etd/1697552482; https://doi.org/10.25773/v5-nq6n-y836; https://scholarworks.wm.edu/context/etd/article/7465/viewcontent/Corso_vims_0261D_10156.pdf

The Antarctic fish fauna is unique, with approximately 88% of the ~375 known species endemic to the Southern Ocean. One group, the perciform suborder Notothenioidei, dominates fish richness and biomass. These fishes possess several traits that allow existence in frigid conditions, but also limit their ability to cope with temperature increases due to climate change. In the western Antarctic Peninsula (WAP) region, a combination of anthropogenic impacts, including climate change and fishing pressure, threaten these fishes. The WAP is one of the most rapidly warming regions globally (3.4 °C per century) and has the highest fishing pressure for Antarctic krill in the Southern Ocean, which can result in the bycatch of larval nototheniods. The goal of my dissertation is to utilize interdisciplinary techniques to better understand the diversity of these unique fishes, as well as more accurately predict how their early life stages will respond to future conditions. Data in my dissertation are sourced from the Palmer Antarctica Long-Term Ecological Research (Palmer LTER) program, established in 1990 to study the pelagic ecosystem of the WAP. Larval fishes are captured annually as bycatch in Palmer LTER zooplankton net tows and represent the longest running (30+ years), fisheries-independent time series of Antarctic fishes. In Chapter 2, I utilize this novel time series to model the impacts of environmental change on Pleuragramma antarctica (Nototheniidae) larvae. Adult P. antarctica use sea ice as spawning habitat and are important prey for penguins and other predators. I show that warmer sea surface temperature and decreased sea ice are associated with reduced larval abundance, indicating these keystone fish could disappear regionally in the near future. In Chapter 3, I employ a combination of morphological and genetic analyses to describe unknown early life stages of a rare notothenioid genus (Akarotaxis; Bathydraconidae), which led to the discovery of a new species, Akarotaxis n. sp., that is described in Chapter 4. ...