Thesis (M.Phil) - University of St Andrews, October 2007.

Thesis (Ph.D.) - University of St Andrews, September 2008.

Thesis (M.S.) in Wildlife Ecology--University of Maine, 2005. / Includes vita. Includes bibliographical references (leaves 60-64).

Thesis (Ph.D.) - University of St Andrews, April 2010.

<p>The ultimate goal of wildlife recovery is abundance growth of a species, though it must also involve the reestablishment of the species’ ecological role within ecosystems frequently modified by humans. Reestablishment and subsequent recovery may depend on the species’ degree of adaptive behavior as well as the duration of their functional absence and the extent of ecosystem alteration. In cases of long extirpations or extensive alteration, successful reestablishment may entail adjusting foraging behavior, targeting new prey species, and encountering unfamiliar predatory or competitive regimes. Recovering species must also increasingly tolerate heightened anthropogenic presence, particularly within densely inhabited coastal zones. In recent decades, gray seals (Halichoerus grypus) recovered from exploitation, depletion, and partial extirpation in the Northwest Atlantic. On Cape Cod, MA, USA, gray seals have reestablished growing breeding colonies and seasonally interact with migratory white sharks (Carcarodon carcharias). Though well-studied in portions of their range due to concerns over piscivorous impacts on valuable groundfish, there are broad knowledge gaps regarding their ecological role to US marine ecosystems. Furthermore, there are few studies that explicitly analyze gray seal behavior under direct risk of documented shark predation. </p><p> In this dissertation, I apply a behavioral and movement ecology approach to telemetry data to understand gray seal abundance and activity patterns along the coast of Cape Cod. This coastal focus complements extensive research documenting and describing offshore movement and foraging behavior and allows me to address questions about movement decisions and risk allocation. Using beach counts of seals visible in satellite imagery, I estimate the total regional abundance of gray seals using correction factors from haul out behavior and demonstrate a sizeable prey base of gray seals locally. Analyzing intra-annual space use patterns, I document small, concentrated home ranges utilizing nearshore habitats that rapidly expand with shifting activity budgets to target disperse offshore habitats following seasonal declines in white sharks. During the season of dense shark presence, seals conducted abbreviated nocturnal foraging trips structured temporally around divergent use of crepuscular periods. The timing of coastal behavior with different levels of twilight indicate risk allocation patterns with diel cycles of empirical white shark activity. The emergence of risk allocation to explain unique behavioral and spatial patterns observed in these gray seals points to the importance of the restored predator-prey dynamic in gray seal behavior along Cape Cod.</p> / Dissertation

Thesis (Ph. D.)--University of Helsinki, 2000. / Includes bibliographical references (p. 35-43). Also available in electronic format via Internet.

No description available.

Neonatal mortality in grey seals on the Isle of May breeding colony and in a rehabilitation centre were investigated by detailed systematic post-mortem examinations (n=59), on-site bacteriology and advanced molecular diagnostic techniques for specific pathogens. Causes of death on the breeding colony included starvation (30%), omphalitis-peritonitis (26%), septicaemia (22%), stillbirth (10%) and trauma (4%) and in the rehabilitation centre starvation (44%) and septicaemia (22%). Detailed key gross and histopathological findings and pathogens are described and include the first report of Listeria monocytogenes in any marine mammal. Phocid herpes virus 1 nucleic acids were detected in nasal swabs of 58% live, free-ranging grey seal pups (n=90) and 28% yearlings (n=19), suggesting recrudescence in the latter. Previously undetected in Scotland, phocid herpes virus 2 nucleic acids were identified only in yearlings (15%); sealpox was detected in a single live stranded grey seal pup and phocine distemper virus was not detected. Given their unique characteristics and potential for acting as sentinels of coastal marine health several pathogens of putative anthropogenic origin were investigated: Toxoplasma gondii, Neospora caninum, Salmonella spp. and Campylobacter spp. Toxoplasma gondii DNA was detected in 6% dead free-ranging grey seal pups (n=50) but N. caninum was not found. Salmonella (20%) and Campylobacter (50%) were isolated from rectal swabs of live and dead grey seal pups and Campylobacter was significantly associated with moderate to severe colitis implying pathogenicity. These findings imply a land-sea-land transfer of T. gondii and early exposure of pups to this parasite. Extensive genetic fingerprinting suggested an exchange of Salmonella between grey seal, cattle and human populations and that the Campylobacter isolates may share the same origin as human clinical isolates. This work provides a solid base line study of diseases present in grey seal pups and demonstrates that they are useful indicators of coastal marine microbial contamination.

This thesis examines fatty acid (FA) and polychlorinated biphenyl (PCB) dynamics in a marine top predator, the grey seal (Halichoerus grypus,) and their transfer during lactation from mother to offspring. It examines regional and annual variations in FA composition and PCB loads, and also how the physical and chemical characteristics of these molecules (e.g. their polarity and size) can affect the rates of accumulation, mobilization and transfer of specific FAs or PCBs. Two UK grey seal colonies (North Rona (NR) and Isle of May (IOM) were studied during three consecutive years (1996-1998 and 2004-2006). Lactating grey seals and their pups were repeatedly captured during the lactation period and sampled for blubber, serum and milk and analysed for FAs and PCBs. Overall, the two colonies were clearly distinguished from each other, suggesting that the main prey species had different FA composition, and possibly that the seals from these colonies had different diets . These differences are probably a direct consequence of differences in prey community structure in the two regions where seals from these two colonies are thought to feed. Within each colony, annual differences could be detected between some years but not between others. During 1996-98, IOM seals showed a clear change in their FA profiles while NR seals did not. In contrast, during 2004-2006 NR seals showed a clear change while IOM seals did not. The changes observed in IOM during 1996-1998 are consistent with the large-scale regime shift that occurred in the North Sea during the 1990‟s. The relative proportions of each FA that were mobilized from blubber and transferred to the milk during lactation were very similar between colonies, and could be explained to a large degree by their physico-chemical properties. For a given carbon chain length the mobilization increased with increasing number of double bonds; and for a given number of double bonds the mobilization decrease with increasing carbon chain length. However, the mobilization also appeared to be influenced by the specific nutritional requirements of the growing pups. For instance, FAs that are considered essential for pup development or efficient energy storage (e.g. saturated FAs) were more highly mobilised than expected. This selectivity was also reflected in the FA composition of the different body compartments (maternal blubber and milk, pup blubber) that persisted throughout lactation. These changes were also similar between the colonies. Colonies could also be clearly distinguished by their blubber PCB profiles. IOM seals had higher total concentrations on average than NR seals (1327.9 vs. 680.2 ng/g lipid in 2005 and 1199.7 vs. 819.0 ng/g lipid in 2006). IOM seals also had higher total amounts in both years (79.2 vs. 38.0 mg in 2005 and 61.7 vs. 53.4 mg in 2006). One of the main differences between colonies was that females from IOM had higher concentrations of highly chlorinated congeners than NR seals. PCB concentrations in blubber increased towards the end of lactation. Serum and milk PCB concentrations also increased rapidly, especially for the highly chlorinated congeners. These results were consistent with other studies showing the increase in concentrations as a result of lipid loss. Serum concentrations stayed constant during the first part of lactation and increased at late lactation. This was also observed in milk PCB concentrations. The changes in the PCB profiles in the three body compartments were very similar between colonies. However IOM seals always had higher total concentrations of PCBs in all of the body compartments. The concentrations of individual congeners relative to PCB-153 showed that blubber contained higher proportions of the highly chlorinated PCBs relative to other tissues. There were no clear changes in these proportions in blubber during lactation, but the relative proportions of highly chlorinated PCB In serum and milk increased throughout lactation while the less chlorinated PCBs stayed constant. The highly chlorinated PCBs were found in lower concentration in the milk compared to the less chlorinated compounds suggesting a selective release from blubber to blood and a selective transfer of PCBs to the milk.

Thesis (Ph.D.) - University of St Andrews, May 2007.