Weddell seals (Leptonychotes weddellii) are among the deepest diving pinnipeds (i.e., seals, sea lions, and walrus) and one of the best studied marine mammals in the world; as such, these seals are considered a model species for the study of diving physiology and behavior. Adult Weddell seal dive physiology is rather comprehensively understood, yet previous research has excluded an examination of pups’ initial independent diving attempts, beginning instead with the diving capabilities of near-weaning individuals at four to five weeks of age. This is beyond the point many pups have attempted their first independent dives; pups begin to enter the water at 8-10 days after birth, with some observed in the water earlier. The aim of this study was to investigate the development of diving capabilities and fine-scale behaviors of Weddell seal pups beginning at one week of age throughout their dependence period. Pups were sampled longitudinally at 1, 3, 5, and 7 weeks of age. Total body oxygen stores (TBO2, mL O2) were calculated as the sum of blood, muscle, and lung oxygen stores for each seal at all time points. Blood samples were collected under sedation, muscle oxygen parameters were interpolated, and lung oxygen content was extrapolated from adult values. Flipper-mounted time-depth recorders were used to collect concurrent dive behavior data. In chapter 1, I hypothesized that diving capability (TBO2) would be more strongly correlated with dive experience than calendar age; to examine this, age, mass, and diving parameters were correlated with oxygen stores. I instead found mass and age were most significantly correlated with individual tissue oxygen stores and TBO2. I predicted diving experience would be an important driver of oxygen storage development due to hypoxia exposure, but pups spent the majority of their time in the water at the surface and had little to no exposure to hypoxia during dependence. Increases in mass may enable early advances in diving ability, and with increased diving capabilities, pups will be able to become successful independent foragers. Later exposure to hypoxia may be the key to the subsequent increases in TBO2 observed in yearlings and juveniles. In chapter 2, I used TDR data to predict when pups would be in the water based on developmental, temporal, and environmental factors including age, weaning status, time of day, and weather parameters. Pups spent the most time in the water and made their deepest, longest, and most frequent dives during the late night and early morning hours. These data indicate pups are following the diving patterns of their mothers, which follow the diurnal vertical migration of their prey. The data also suggest Weddell seal pups most likely prioritize learning to swim and navigate as opposed to practicing foraging while still dependent. It is critical for pups to develop their swimming, navigational, and diving abilities while they are still with their moms to ensure their survival. This study is the first to describe the complete trajectory of the development of diving physiology and behavior in Weddell seal pups throughout dependence. It is important to understand how the internal diving physiology of Weddell seal pups develops because this directly determines their diving capabilities and their ability to forage successfully, which in turn directly correlates with their survival. Pup survival is an indicator of population growth rates, so the development of diving physiology in pups can lend insights into larger population-level trends.

<p>Effective conservation strategies for sea turtles require knowledge of animal movements and protection of biologically important habitats and life history stages. For breeding adult sea turtles, understanding both their inshore and pelagic spatial patterns is imperative to the successful protection of the species and the accurate identification of their vulnerabilities. This study provides insight into the inter-nesting, post-nesting, and foraging movements of green sea turtles (<i>Chelonia mydas</i>) that nest on Bioko Island, Equatorial Guinea, by using satellite telemetry to track green turtles (n=12) during two nesting seasons (2017-18, 2018-19), and as they migrated to foraging grounds after the nesting season. These tracks were fit with a switching state space model to characterize movements, and then analyzed in relation to environmental and anthropogenic factors. Dive depth data was also used to determine utilization patterns within the water column. The 12 tagged turtles migrated for an average of 1064 km to two distinct foraging grounds, with 10 migrating west for an average of 1115 km to the coastal waters of Ghana, and 2 migrating south for an average of 1563 km to the coastal waters of Angola. Migrating turtles used both direct, pelagic migration strategies, and biphasal, coastal strategies, which included intermittent foraging throughout migrations. Dive depths varied depending on behavior, with an average of 19.3 m during inter-nesting, 12.6 m during migration and 8.5 m during foraging. Knowledge of inter-nesting habitat use, migration patterns, and foraging ground locations will be critical for the development of marine conservation management plans in the Gulf of Guinea and aide in sea turtle conservation efforts throughout the area. Additionally, spatial and dive depth data can inform zonal fishing regulators and provide information needed for modifications to fishing practices and gear that is most likely to reduce sea turtle bycatch. These data will provide a more complete understanding of marine areas critical to sea turtle conservation and aide in sustainable economic development in the Gulf of Guinea.</p><br>