Sperm whales (Physeter macrocephalus) are widely distributed in all oceans, but principally found in areas of high primary productivity. Historically, they were whaled extensively in the Sargasso Sea and recent surveys have also found large numbers there. However, the Sargasso Sea is an oceanic gyre considered to be low in productivity. This dissertation explores the paradox of a high abundance of large top predators in a body of water once described as an “oceanic desert”. First, I compared the diet of sperm whales in the Sargasso Sea to those off Dominica, in the eastern Caribbean. Results suggested differences in trophic ecology between these two areas, with sperm whales in the Sargasso Sea feeding at a higher trophic level. Second, I examined the spatial and temporal distribution of sperm whales in the Sargasso Sea in relation to environmental variables using acoustic surveys and autonomous recording devices. Sperm whale prevalence around Kelvin seamount, part of the New England Seamount Chain, was higher in the spring compared to the winter. Habitat modeling results suggest that the mesoscale activity associated with the Gulf Stream plays an important role in sperm whale occurrence in this area, likely due to the enhancement of primary productivity in this region. Finally, I estimated the current density of sperm whales in the northwestern Sargasso Sea and compared their present distribution to their distribution during the open-boat whaling era (1775-1921). Sperm whale density in the northern Sargasso Sea is one of the highest found globally, showing that this region remains a hotspot for sperm whales. The area where sperm whale detections per unit effort is presently the highest showed little overlap with areas where whales were hunted historically. Whalers all but ignored this region except when transiting to other whaling grounds, perhaps a result of fixed whaling patterns due to the conservative use of knowledge at that time. My dissertation highlights patterns and processes that help to explain the presence and abundance of sperm whales in the Sargasso Sea and demonstrates the importance of western boundary currents, such as the Gulf Stream, to the distribution of marine top predators.

I examined the dynamics of an endangered population of northern bottlenose whales over a 23-year period during which its prime habitat, the Gully canyon, was made a Marine Protected Area (MPA). Using mark-recapture techniques on photo-identifications I estimate a current population of 116 animals (95% CI=101-130). The population size and sex-ratio have remained stable since before the MPA designation suggesting this population is persisting. I used photo-identifications and high definition videography to examine the social organization of northern bottlenose whales, including behavioural synchrony. Relationships are highly variable; most associations are short-lived, but there are also long-term preferred associations lasting from several years (female/immature dyads) to over a decade (mature male dyads). I found little, if any, division of the social community. Synchronized breathing is common, precise, and appears to vary with behaivoural context. Although speculative, synchronized breathing might play a role the maintenance of general social relationships within this population.

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Many of the factors that shape contaminant accumulation profiles in marine mammals also strongly influence fat soluble vitamin accumulation. Vitamin A and E are essential fat soluble nutrients for numerous biological processes, including reproduction, growth, endocrine and immune function. Contaminants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), can alter vitamin dynamics; as such these vitamins have been proposed as sensitive biomarkers of contaminant exposure in wildlife. In light of these considerations, the present thesis was aimed at better understanding the factors that influence the accumulation of lipophilic contaminants and vitamins in western Arctic beluga whales, and to determine if there was an interaction between the two. Maternal offloading to neonates during gestation reduced overall contaminant (PCBs and PBDEs) and vitamin (A and E) concentrations in reproductively active female whales. The PCB and PBDE congener pattern in mothers changed during gestation as a result of preferential transfer of light-low Log KOW congeners to the fetus. Overall, female beluga whales transferred approximately 11% of their PCB and PBDE blubber burden to their fetus. In terms of vitamins transfer, lower concentrations of tocopherols, retinol and retinyl esters were found in reproductively active females relative to males and reproductively inactive females. Metabolism was also found to be an important factor for contaminant and vitamin accumulation in beluga tissues. In a principal components analysis, PCBs clustered into metabolically-derived structure-activity groups, which separated along the first principal component according to its metabolic potential (metabolizable vs. recalcitrant). Contaminant-related up-regulation of metabolizing enzymes, including cytochrome P450, likely explained changes in the concentration and pattern of PCB and PBDE congeners, as well as hepatic, plasma, and blubber vitamin A and E. Since vitamins and lipophilic contaminants accumulated in beluga whales in the same way in relation to most biological processes, including sex, reproduction, size, condition, and feeding ecology, it was important to control and reduce the number of these confounding factors before claiming any tissue vitamin change was indeed the result of chemical exposure. In doing so, it was found that vitamin A and E homeostasis was influenced by PCBs in beluga whales, resulting in reduced hepatic storage and increased plasma and blubber concentrations. Overall, these results suggest that liver, plasma, and inner blubber vitamin A and E concentrations can be sensitive biomarkers of contaminant exposure only if major confounding effects are taken into consideration. The implications of altered vitamin dynamics on the health of beluga whales is unknown at this time; however, as Arctic marine mammals face continued stress related to climate change, increased human disturbance and emergence of infectious diseases, this study can serve as essential baseline data that can be used to monitor the health status of western Arctic beluga whales. / Graduate / 0383 / 0329 / 0768 / jpdesforges@gmail.com

This thesis examines the human and animal dimensions of whale-watching and develops a framework for management of the humpback whale-watching industry in New South Wales (NSW), Australia. The short-term responses of humpback whales to whale-watching vessels during their southward migration on the south coast of NSW were assessed. The behaviour of pods was recorded from commercial whale-watching vessels during tours and compared to pods in the absence of vessels observed from shore in the same area. Pod sizes and composition were typical of southward migrating whales. Calf pods were more sensitive to the presence of vessels than non-calf pods. Whilst there was a longer dive time and a greater percentage of time spent submerged by whales in the presence of vessels, there were no associated changes in respiration intervals. Some surface behaviours were suppressed in the presence of vessels. Surface-active behaviours were prevalent in this study which indicates that social interactions amongst conspecifics are common during the southern migration. Feeding pods were observed on 24.5% of all whale-watching trips and during 14% of all observations made from shore. South-eastern NSW is probably a significant supplemental feeding ground for migrating whales. Feeding behaviour did not alter in the presence of vessels but the time between feeding lunges increased when vessels were closer than 100 m and when more than one vessel was present. The demographics, expectations, experience and satisfaction of land-based and boat-based whale-watchers in NSW were assessed by a questionnaire to participants. Land-based whale-watchers had high and often unrealistic expectations about their whale-watching experience and were moderately satisfied. Boat-based whale-watchers had high, but often realistic expectations of their experience and were highly satisfied. Satisfaction was a function of the degree to which expectations were met, the proximity of whales, the numbers of whales, their behavioural displays and the level of information available on whales. Whale-watchers showed limited increase in their knowledge and conservation-oriented behaviours over the long term. Current education about whales requires better structure and clearer conservation objectives. This study identifies research, education and vessel management as three fundamental components for the sustainable management of the whale-watching industry, and makes recommendations incorporating these components.

Every year hundreds of cetaceans strand on New Zealand beaches. Options for dealing with disposal of their carcasses are few, creating significant problems for the Department of Conservation (DOC). More often than not their carcasses are buried in beaches at or just above high water mark, near where the animals have stranded. The primary objective of this thesis is to determine the effects of cetacean burial on beach sediments, and evaluate potential health and safety risks associated with this practice. A secondary objective of this thesis is to appraise the appropriateness of one location DOC has repeatedly transported cetacean carcasses to and buried within beach sediments, Motutapu Island in Waitemata Harbour. The chemical effects of cetacean burial over a six-month period are reported for two sites at which animals were buried in 2008, Muriwai and Pakiri beaches; the biological effects of this burial are reported for one of these sites, Muriwai Beach, 12 months post burial. Intertidal faunal and floral inventories are provided for six sites around Motutapu Island, and these then compared and contrasted with inventories compiled from an additional 290 intertidal sites between Whangarei Heads and Tauranga Harbour, North Island East Coast, to appraise the relative uniqueness of intertidal species diversity around Motutapu Island. At both Muriwai and Pakiri beaches, nitrogen and phosphate concentrations in surface sands changed considerably following cetacean burial, although over six months the effect was localized and elevated concentrations of these two chemicals that could be attributed to a buried carcass did not extend more than 40 m from the site of whale burial. Deep-core profiles revealed nitrogen and phosphate concentrations at and in the immediate vicinity of cetacean burial approximately six months after burial to be markedly elevated to the level of the water table, but elevated concentrations attributable to the buried carcass were not observed greater than 25 m from the site of burial. Elevated concentrations of nitrogen and phosphates in beaches persist in surface sediments for at least six months post burial. Twelve months post cetacean burial no significant difference in species richness or abundance were apparent in intertidal communities extending along transects proximal to and some distance from the Muriwai Beach carcass; there is no evidence for any significant short-term (to 12 months) biological effects of cetacean burial in beaches. Of those shores on Motutapu Island accessible by earth-moving equipment and large vessels capable of dealing with and transporting large cetacean carcasses, Station Bay appeared to be the most appropriate site for whale burial. However its small size and relatively high biological value (fairly high species richness for comparable shores between Whangarei Heads and Tauranga) renders it an inappropriate long-term option for whale burial. Other shores on Motutapu Island host some of the highest species richness of all shores surveyed between Whangarei Heads and Tauranga Harbour, rendering them entirely inappropriate locations for burying cetaceans, over and above other variables that may influence disposal location identification (such as archaeological sites, dwellings and accessibility). Motutapu Island is not considered an appropriate location for cetacean burial within beaches. Alternative disposal strategies need to be explored for dealing with cetaceans that strand on Auckland east coast beaches. Although burial is the most convenient and most economical strategy to dispose of cetacean carcass, especially in mass stranding events or when cetaceans are of large size, and the biological effects of this practice are not considered significant (for the one whale that could be studied), persistent enrichment of beach sediments with organic matter could result in prolonged persistence of pathogens in beaches, causing unforeseen risks to human health and safety. Recommendations are made to minimize possible threats to public following burial of cetaceans in beaches, until the potential health risks of burial are more fully understood.

The conservation status of the widely-distributed whale shark Rhincodon typus is presently listed as 'Indeterminate - Data Deficient'. One of the main hindrances to obtaining biological data on whale sharks that is relevant to determining its 'conservation status' is that this species has rarely been recorded as occurring in sufficient numbers to obtain quantitative data. However, R. typus does form aggregations at Ningaloo Marine Park (NMP), Western Australia, annually between March and June. This has enabled studies to be made of aspects of the biology of R. typus and of the possible impacts of the ecotourism industry on this species. Using a position provided on vessels involved with the whale shark ecotourism industry at NMP, R. typus was observed on 360 separate occasions in 1995, 1996 and 1997, and it was possible to sex 90.3% of these sharks. The majority of the sexed sharks (84.6%) were male and ranged in length from 4 to 12 m, with a mean of 7.4 m, while the females ranged in length from 4.5 to 8.5 m, with a mean of 6.2 m. The size and degree of abrasion of the claspers was used as an indicator of whether or not a male shark had mated. Using such criteria, it was estimated that male whale sharks start to mature at ca 8 m and that ca 50% are mature by the time they reach 8.6m. Observations suggested that R. typus feeds by using both suction and flow-through mechanisms. The prey that were observed being ingested included coral spawn, tropical krill, mysids and small jellyfish. The contents of a faecal sample contained parts of the exoskeleton of copepods and the scales of small fishes. The degree of mouth distension, which is assumed to be related to feeding activity, was low during most observation periods. Photographs of the scars and natural patterning on the skin of individual sharks were used to construct a photographic library for subsequent identification of these sharks. The features used for identifying individual sharks were chosen because they were considered likely to remain for a protracted period. The Whale Shark Photo -identification Library that was produced provides details on the characteristic features of 52 R. typus that were present at NMP. Six individuals were recorded at NMP in both 1995 and 1996, four in both 1996 and 1997, and one in both 1995 and 1997. No identified whale sharks were recorded in all three years. Rhincodon typus was distributed widely throughout NMP, with most boat and aerial sightings lying within 1 - 2 Ism of the reef crest between Tantabiddi and Turquoise Bay. Rhincodon typus was typically sighted in water depths of 10 to 30 m. The sharks were predominantly travelling parallel to Ningaloo Reef, with significantly more moving in a northward than southward direction. Acoustic tracking of R. typus in 1997 suggested that this species remains within NMP for extended periods and is at the surface for ca 17% of daylight hours. The number and species of fauna observed to be associated with R. typus were recorded, and a new species of copepod, Pandarus sp. nov., which lives on the skin of R. typus has been described. Golden trevally (Gnathanodon speciosus), miscellaneous trevally (Carangid sp.), remora (Remora sp.) and slender suckerfish (Echeneis naucrates) were common. The prevalence of Pandarus sp. nov. was inversely proportional to the number of Remora sp. and E. mucrates in 1996, while the opposite was true in 1997, suggesting that Pandarus sp. nov. were preyed on by these diskfish. Rhincodon typus is the basis of the ecotourism industry that operates within NMP each year. While there was considerable variation in the number of tour vessels searching for whale sharks at NMP each year, the greatest mean number of vessels operating per week in successive whale shark seasons were 6.7 during Week 8 (April 19 - 25) of 1995, 6.1 during Week 7 (April 12 - 18) of 1996 and 6.9 during Week 8 (April 19 - 25) of 1997. The greatest mean numbers of whale sharks sighted per week in each year were 5.1 during Week 14 (May 31 - June 6) of 1995,4.2 during Week 6 (April 5 - 11) of 1996 and 4.1 during Week 8 (April 19 - 25) of 1997. Tourists, who were permitted to swim alongside R. tyus, interacted with sharks for a mean period of 19.3 rnin in 1995, 14.2 min in 1996 and 9.5 rnin in 1997. The reduction in the duration of interaction in three successive years suggests that, over time, R. typus may have become slightly less tolerant of the ecotourism industry at NMP. The mean minimum distance between vessel and shark during each interaction was 20.7 m in 1995, 21.3 m in 1996 and 31.0 m in 1997. The mean minimum distance between tourist and shark during each interaction was 1.5 m in 1995, 2.05 m in 1996, and 2.1 m in 1997. The mean minimum distance of vessel and tourist from R. typus during each individual interaction decreased as the duration of the interaction increased. Therefore, both R. typus and this industry must be carefully monitored to ensure that the impacts of humans are kept to a minimum and thereby ensure that whale sharks return to NMP each year. An ethology of whale shark behaviours, which included banking, porpoising, diving and eye-rolling, was produced in an attempt to determine whether there is evidence that the ecotourism industry has a negative impact on R. opus at NMP. The frequency of behavioural change was greatest in the first 0 - 5 min of an observation. Eye-rolling by R. typus was recorded as a reaction to flash-photography, while banking was often recorded when SCUBA was used and/or tourists swam beneath the head of the shark. The swimming speed of R. typus at NMP was rarely too fast for tourists to maintain proximity to the sharks. Several sharks possessed both recent and healed scars, which were probably inflicted by vessel contact. The recent wounds indicate that vessels had caused injuries to R. typus within NMP. These individuals tended to display a higher frequency of avoidance behaviours and reduced interaction times. Recommendations are provided to the Western Australian Department of Conservation and Land Management which are aimed at reducing the potential deleterious effects of the ecotourism industry on the whale sharks at NMP.

Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (January 14, 2010) Includes bibliographical references (p. 82-94)