The study was carried out in Kamberg Nature Reserve (Natal Drakensberg) from June 1994 to August 1995. Seven spotted-necked otters were fitted with an intraperitoneal radio-implant; radio-tracking was performed by both temporally independent locations and 24h continuous tracking sessions. When active, otters were always found in aquatic habitats, mainly dams, the river or oxbow lakes. Dense vegetation cover, as trees, reeds, and tall grass were preferred while resting. Otters were active both during the day and during the night, with peaks of activity at twilight. The amount of time spent in consecutive activity varied seasonally together with the main prey items exploited. Average home range area was 11.3km², including a stretch of river with an average length of 14.8 km. No intersexual nor intrasexual territoriality was detected. Intraspecific relationships varied with the dispersion and availability of food resources. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 59-69). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 59-69). Also available on the Internet.

Knowledge of reproduction in the river otter, Lutra canadensis, and of the factors which control the reproductive cycle, is limited. The reproductive biology of river otters in the marine environment of British Columbia, and some of the factors which may influence their reproductive cycle, in particular, the effect of photoperiod, were examined. The changes that occurred in the anatomy, histology and endocrinology of the annual reproductive cycle were determined in wild (226 male, 146 female) and captive (9 male, 5 female) otters. Reproductive cycles were similar in both groups. As in the fresh-water environment, coastal otters are seasonal breeders with a prolonged, obligatory period of embryonic diapause prior to implantation. Changes were similar to those reported in other mustelids. In males, development of the seminiferous tubules was divided into a series of nine distinct phases used to quantify the degree of reproductive activity present. Testosterone concentrations were highly correlated to changes in testicular activity, and fell into the low end of the range of concentrations seen in mustelids. Vaginal smear types were found to identify correctly the reproductive state of female otters. Estradiol concentrations of captive otters were highly variable, but the values obtained and the pattern of secretion were similar to those of other carnivores. Although estradiol levels of captive otters were reduced in the final two years of the study, normal ovarian development occurred. During pregnancy, progesterone concentrations corresponded to changes observed in luteal cell cytology. I present evidence suggesting that female otters are monestrous, induced ovulators. The timing of reproductive events of otters in the marine environment was similar to those of otters inhabiting fresh water at comparable latitudes. Reproductive activity of males began in the late autumn and adults were capable of breeding from late January through mid-May. Females exhibited estrus from late February through mid-May, with the majority of matings probably occurring during March and April. After a nine to eleven month period of embryonic diapause, implantation occurred the subsequent February. Births occurred after an estimated two month gestation and parturient 1 otters mated during lactation. Male otters were sexually mature at the end of their second year. Only 55% of females bred at age class 2 and sexual maturity was delayed until the following year in the remainder of the females. Pregnancy rates were high among females over 3 years of age and ovulation rates were similar to those of other studies. To determine the influence of photoperiod on the timing of reproductive events, captive otters were exposed to increased photoperiods. With one exception, spermatogenesis and estrus occurred earlier under experimental conditions. My results suggest that the termination of embryonic diapause is also under photoperiodic control. Variations in temperature or food were not associated with changes in reproductive condition. This study suggests that photoperiod probably controls the timing of the reproductive cycle of otters in British Columbia. / Science, Faculty of / Zoology, Department of / Graduate

This thesis traces the history of the abalone fisheries on the California Coast and how those fisheries have been understood and shaped by humans over time. An overarching interest that guides this effort is how indigenous populations used abalone and otters (as well as other marine resources) purposefully for millennia prior to European arrival. However, this work is not entirely focused on prehistory. Instead, it shows how a lack of understanding of this prehistory shaped the conservation efforts of the California Department of Fish and Game and its ultimate decision to close the commercial fishery in 1997. In this sense, there is a layer of this thesis that takes on the form of an institutional history of the California Department of Fish and Game, but it does so as a model of how management practices were developed and implemented during the twentieth century. In this frame, this thesis in also a history of twentieth century ecological and scientific practices that historicizes the closure of the commercial abalone fishery in 1997.

Otter populations declined drastically across many areas of England and Wales during the 1960s to 1980s. The main cause of this decline is thought to have been high concentrations of organic pollutants, in particular PCBs and dieldrin. Here we look at the health of the present day otter population, focussing on the numbers of otters, the genetic diversity of populations and investigating a possible new organic pollutant threat, polybrominated diphenyl ethers (PBDEs). A non-invasive spraint genotyping study of the otter population inhabiting the River Camel in Cornwall not only revealed that the river was capable of supporting a minimum number of 12 otters over a 9 month period, but gave insight into the ranges and genetic relationships of the individuals using the river system. A further population genetic study was carried out focussing on the River Itchen in Hampshire, a population which declined drastically to just a few isolated individuals before receiving otters through a captive breeding programme. Microsatellite genotyping of tissue samples showed the River Itchen population to be relatively diverse, indicating a successful population recovery, and haplotype analysis reveals that captive bred otters have successfully bred within the River Itchen population. However, haplotype analysis also indicates that the otters used to found the captive breeding programme were unlikely to have originated from a native British population. Concentrations of PBDEs in otters rival the high concentrations observed in many marine mammal species and are approaching the concentrations of PCBs and DDTs already observed in otters. The profile of the PBDE congeners found shows that lower congeners show relative concentrations similar to those observed in many other species of biota, with high BDE-47 dominating the profile and BDE-99 and -100 also found at significant concentrations. Otters also contain relatively high concentrations of the congeners BDE-153 and BDE-209, a trend generally typical of terrestrial top predators. In summary, the otter populations studied appear to be recovering well. However, increasing concentrations of PBDEs may cause problems for otter populations in the future.

Habitat associations of sea otters during resting and feeding were investigated in Simpson Bay, Prince William Sound, Alaska during the summer months of 2001-2003. Sea otter locations collected during boat surveys were overlaid on bathymetry and sediment maps and water depth, sediment type, distance from shore, and position in the bay (peripheral vs. central) was determined for each. Logistic regression analysis was used to determine whether sea otter habitat use was non-random according to any of these habitat variables. Water depth was the most significant habitat association for feeding behavior, with the majority of feeding dives occurring in shallow water less than 20m deep. Position in the bay was the most significant habitat association for resting behavior, with more otters resting in the center of the bay. In addition, digital images taken of the sea otters during the boat surveys of 2002 and 2003 were used to examine the potential of using nose scars to photo-identify individual sea otters. Both male and female sea otters bore nose scars. Forty-five percent of all individuals encountered were considered identifiable from nose scars and a total of 114 individuals were identified. This compares favorably with the results of photo-identification studies of other marine mammals, suggesting that photo-identification may be a useful tool for the individual identification of sea otters as well.

This thesis deals with Tlingit notions about death, spirits, land otters and shamans. The linkage between these categories and their relationship to the social order are explored by examining Tlingit mythology. Particular myths are analyzed that embody the concepts and beliefs which the Tlingit used to deal with the unanswerable question: What happens when someone dies? Socially, there was a set pattern of ritual practices and a series of memorial feasts to dispense with the body and spirit of someone who died a normal death. Yet, there was an anomalous situation associated with death by drowning or being lost in the woods. The Tlingit indicated that people who died in this manner were taken by land otter spirits and could become shamans if certain conditions were met. This thesis contends that this explanatory scenario was an important aspect of Tlingit cosmology, since it provided a means of illustrating the source of shamanic power, and also of how that power was related to the social aspects of Tlingit culture. The myths dealing with land otter possession offer information about how shamanic power was attained and also provide a glimpse into the importance of the role of the Tlingit shaman as a mediator between the social and the spiritual domains. / Arts, Faculty of / Anthropology, Department of / Graduate

No description available.

Ecology has been devoted to defining the content of a species’ environment. Defining the extent, or size, of a species’ environment is also pivotal to elucidating species-habitat relationships. More than a home range, this extent integrates an individual’s lifetime experiences with resources, competition, and predators. I theorised that a species’ habitat extent is identifiable from its characteristic spatial scale of habitat selection, which in turn is predicted by body size. I reviewed scale-dependent mammalian habitat selection studies and found that a characteristic scale was typically not identified, but identifiable. Of several ecological predictors tested, only body mass was a significant predictor of the relative size of a species’ characteristic habitat selection scale. Tests of existing data are confounded by differing approaches, so I empirically tested the scale-body mass hypothesis using a standardised survey of 12 sympatric terrestrial mammal species from the Canadian Rocky Mountains. For each species, support for habitat models varied across 20 scales tested. For six species, I found a characteristic selection scale, which was best predicted by species body mass in a quadratic relationship. Occurrence of large and small species was explained by habitat measured at large scales, whereas medium- sized species were explained by habitat measured at small scales. The relationship between body size and habitat selection scale is congruent with the textural-discontinuity hypothesis, and implies species’ evolutionary adaptation to landscape heterogeneity as the driver of scale-dependent habitat selection. I applied this principle to examine wolverine habitat selection, and found that anthropogenic fragmentation of the landscape influences that species’ occurrence in space at large spatial scales. Finally, I contended that the prevailing paradigm equating habitats to resources omits interspecific interactions that are key predictors of a species’ occurrences. I examined habitat selection of martens and fishers in terrestrial environments, and sea otters in marine coastal environments, and tested whether the presence of heterospecifics could explain spatial occurrence beyond landscape structure and resources. In both cases, the presence of heterospecifics explained species occurrence beyond simple resource selection. Interspecific interactions are key drivers of a species’ distribution in space; this is the spatial expression of the concepts of fundamental and realized niches. Body size interacts with landscape structure to determine the scale of a species’ response to its environment, and within this habitat extent, interspecific interactions affect the species’ pattern of occurrence and distribution. / Graduate