The Effects of Environmental and Climate Variability on Antarctic Krill Reproductive Development, Condition and Recruitment at the Antarctic Peninsula

• Main Author: Steinke, Kirsten
• Other Authors: Bernard, Kim S., Ciannelli, Lorenzo, Reiss, Christian, Menge, Bruce, Kavanaugh, Maria, College of Earth, Ocean, and Atmospheric Sciences
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Antarc*; Antarctic; Antarctic Krill; Antarctic Peninsula; Euphausia superba; Sea ice; Southern Ocean
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/tx31qs774

Antarctic krill, Euphausia superba (hereafter, krill), is a critical species in Antarctic ecosystems, serving as the primary food source for top predators and accounting for more than 90% of the total Southern Ocean fisheries catch by weight. The Antarctic Peninsula is a year-round habitat for krill and supports large populations of whales, penguins, seals, seabirds and fish, most of which depend on large aggregations of krill for survival. Over the last half century, the Antarctic Peninsula has been warming at an unprecedented rate, and the implications of this warming on krill populations in the region are not fully understood. This dissertation explores how environmental and climate change affect krill reproductive development, physiological condition, and recruitment at the northern part of the Antarctic Peninsula (nAP) and the Western Antarctic Peninsula (wAP) using controlled laboratory experiments and in situ data on krill, the climate, and the environment. Examining the reproductive development and physiological condition of female krill across seasons and years at the Antarctic Peninsula has resulted in a more detailed picture of how climate and environmental variability affect krill physiology and reproduction. Notably, I found that if female krill have access to sufficient food throughout the fall and winter, they are able to initiate reproductive development before the onset of spring. In addition to food availability, sea ice dynamics, and seasonal variability in the Southern Annular Mode (SAM) and Multivariate El Niño Index (MEI) are intimately connected to the reproductive development and success, recruitment, and physiological condition of juvenile and adult female krill. Further, if female krill are in good condition during the spawning season, krill recruitment the following year is likely to be more successful. With my dissertation, I have been able to answer fundamental questions about how krill mature, reproduce and survive throughout the year in an ever-changing ecosystem, filling an ...