Kim M. Parsons

Kinship as a basis for alliance formation between male bottlenose dolphins, Tursiops truncatus, in the Bahamas

Alliances between reproductive males have been described in both cetacean and terrestrial mammal societies, and kin selection theory has often been invoked to explain these stable male coalitions. However, recent studies of bottlenose dolphins, Tursiops aduncus, in Australia suggest that mechanisms other than kinship are fundamental in the formation of male alliances. We supplemented skin biopsy sampling with the collection of faecal samples from individually recognized wild bottlenose dolphins, T. truncatus, to assess the role of kin selection in alliance membership in the northeast Bahamas. Stable alliances between pairs of males were identified based on association analyses of individual photoidentification data collected over 4 years. Molecular genetic analyses of tissue samples revealed highly significant correlations between patterns of association and both mitochondrial DNA haplotype identity and microsatellite relatedness, indicating that males within long-term alliances are more closely related than expected by chance. These data reinforce the high degree of plasticity previously reported within the genus Tursiops, and suggest that social and ecological differences between populations can markedly affect the role of kin selection in determining social alliances between male bottlenose dolphins.  2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.

Social network correlates of food availability in an endangered population of killer whales, Orcinus orca

For the majority of social species, group composition is dynamic, and individuals are interconnected in a heterogeneous social network. Social network structure has far-reaching implications for the ecology of individuals and populations. However, we have little understanding of how ecological variables shape this structure. We used a long-term data set (1984e2007) to examine the relationship between food availability and social network structure in the endangered southern resident killer whales. During the summer months individuals in this population feed primarily on chinook salmon, Oncorhynchus tshawytscha, which show annual variation in abundance. We tested the hypothesis that temporal variation in chinook salmon will correlate with variation in social network structure. Using a null model that controlled for population demography, group size and sampling effort, we found a significant relationship between the connectivity of the social network and salmon abundance, with a more interconnected social network in years of high salmon abundance. Our results demonstrate that resource availability may be an important determinant of social network structure. Given the central importance of the social network for population processes such as the maintenance of cooperation and the transmission of information and disease, a change in social network structure caused by a change in food availability may have significant ecological and evolutionary consequences. 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Organochlorine concentrations in resident bottlenose dolphins (Tursiops truncatus) in the Shannon estuary, Ireland

S.D. Berrow *, B. Mchugh , D. Glynn , E. Mcgovern , K.M. Parsons , R.W. Baird , S.K. Hooker e a Shannon Dolphin and Wildlife Foundation, Merchants Quay, Co. Clare, Kilrush, Ireland b Marine Institute, Abbotstown, Castleknock, Dublin 15, Ireland c Department of Zoology, University of Aberdeen, Tillydrone Avenue, Aberdeen AB9 2TN, UK d Department of Biology, Dalhousie University, Halifax, NS, Canada B3M 4J1 e British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK

Mitochondrial genetic diversity and population structuring of UK bottlenose dolphins (Tursiops truncatus): is the NE Scotland population demographically and geographically isolated?

Concern has been expressed over the status of the bottlenose dolphin population that uses the Moray Firth and adjacent waters in NE Scotland. Consequently, part of this populations range has been proposed as a Special Area of Conservation. Efforts to manage and monitor the status of this population require information on the level of genetic diversity within the population and its genetic relatedness to neighbouring populations to appropriately designate units for management and monitoring. Here we examine mitochondrial genetic diversity within the NE Scotland population, and compare this to other regions around the UK and Ireland. Sequence analysis of 549bp of the mitochondrial DNA control region identified eight unique haplotypes in a sample of 29 individuals. Analysis of molecular variance suggests that the Moray Firth population is genetically more closely related to Welsh animals than to its nearest neighbour population in west Scotland. Furthermore, measures of within-population genetic diversity were markedly lower in the Moray Firth than any other sampled region. The low levels of mtDNA genetic variability observed and its apparent geographic isolation provide further support for the precautionary approach currently being applied to the management of this population, despite the lack of direct evidence of harm.

Amplifying dolphin mitochondrial DNA from faecal plumes

© 1999 Blackwell Science Ltd, Molecular Ecology, 8, 1753–1768 for paternity analyses. Six loci that did not amplify reliably but may be useful with different primers are (repeat array followed by GenBank Accession no.): (GA)13 (AF143977); (TG)13 (AF143978); (CT)19 (AF143981); (TG)11 (AF143983); (GA)24 (AF143984); and (CT)23(AT)12 (AF143985). The five loci used for paternity yielded 77 alleles with a mean of 15 alleles per locus. Observed and expected heterozygosities ranged from 0.49 to 0.94. Hardy–Weinberg equilibrium was tested with Fisher’s exact test of genepop version 3.1d (Raymond & Rousset 1995). A significant excess of homozygotes was observed in three populations for DE48 and in five populations for DE54 (Table 1), presumably the result of null alleles. The expected exclusion probabilities for single loci ranged from 0.23 to 0.87 with a multilocus expectation of > 0.995 (Marshall et al. 1998). Together, these loci provided enough variation to resolve paternity for a large portion of the D. excelsa seed population.

The role of menopause and reproductive senescence in a long-lived social mammal

BackgroundMenopause is a seemingly maladaptive life-history trait that is found in many long-lived mammals. There are two competing evolutionary hypotheses for this phenomenon; in the adaptive view of menopause, the cessation of reproduction may increase the fitness of older females; in the non-adaptive view, menopause may be explained by physiological deterioration with age. The decline and eventual cessation of reproduction has been documented in a number of mammalian species, however the evolutionary cause of this trait is unknown.ResultsWe examined a unique 30-year time series of killer whales, tracking the reproductive performance of individuals through time. Killer whales are extremely long-lived, and may have the longest documented post-reproductive lifespan of any mammal, including humans. We found no strong support for either of the adaptive hypotheses of menopause; there was little support for the presence of post-reproductive females benefitting their daughters reproductive performance (interbirth interval and reproductive lifespan of daughters), or the number of mature recruits to the population. Oldest mothers (> 35) did appear to have a small positive impact on calf survival, suggesting that females may gain experience with age. There was mixed support for the grandmother hypothesis – grandoffspring survival probabilities were not influenced by living grandmothers, but grandmothers may positively influence survival of juveniles at a critical life stage.ConclusionAlthough existing data do not allow us to examine evolutionary tradeoffs between survival and reproduction for this species, we were able to examine the effect of maternal age on offspring survival. Our results are consistent with similar studies of other mammals – oldest mothers appear to be better mothers, producing calves with higher survival rates. Studies of juvenile survival in humans have reported positive benefits of grandmothers on newly weaned infants; our results indicate that 3-year old killer whales may experience a positive benefit from helpful grandmothers. While our research provides little support for menopause evolving to provide fitness benefits to mothers or grandmothers, our work supports previous research showing that menopause and long post-reproductive lifespans are not a human phenomenon.

DNA-based identification of salmonid prey species in seal faeces

Assessment of pinniped predation most often relies on analysis of the hard, undigested prey remains evident in faecal (scat) samples. For many prey species this method can yield valuable information on predator–prey interactions. For some genera, however, species diagnostic characteristics are lost during the process of prey digestion, thereby preventing morphological identification of fish prey species. Here, the feasibility of using faecal DNA to detect the presence of salmonids in pinniped scat samples and to distinguish reliably between sea trout Salmo trutta and Atlantic salmon S. salar was assessed. Novel salmonid mitochondrial DNA (mtDNA) primers were designed to amplify 162 bp of the 16S rDNA and a 327 bp section of the cytochrome b gene. Species-specific banding patterns were obtained by digestion of the cytochrome b PCR product with the restriction endonuclease AluI, and confirmed by the species-specific amplification of the 16S rDNA fragment from Atlantic salmon. Scats collected from captive grey seals Halichoerus grypus fed on known monospecific diets used to validate the PCR-RFLP assay indicated a probability of at least 95.8% (23 of 24 faecal extracts) of detecting salmonids using DNA extracted from the scat matrix. Implemented alongside conventional prey remains analyses, this technique presents a promising new method for examining prey composition and assessing pinniped predation on salmonids.

Genetic isolation of a now extinct population of bottlenose dolphins (Tursiops truncatus)

A number of dolphin species, though highly mobile, show genetic structure among parapatric and sometimes sympatric populations. However, little is known about the temporal patterns of population structure for these species. Here, we apply Bayesian inference and data from ancient DNA to assess the structure and dynamics of bottlenose dolphin (Tursiops truncatus) populations in the coastal waters of the UK. We show that regional population structure in UK waters is consistent with earlier studies suggesting local habitat dependence for this species in the Mediterranean Sea and North Atlantic. One genetically differentiated UK population went extinct at least 100 years ago and has not been replaced. The data indicate that this was a local extinction, and not a case of historical range shift or contraction. One possible interpretation is a declining metapopulation and conservation need for this species in the UK.

Geographic and temporal dynamics of a global radiation and diversification in the killer whale

Global climate change during the Late Pleistocene periodically encroached and then released habitat during the glacial cycles, causing range expansions and contractions in some species. These dynamics have played a major role in geographic radiations, diversification and speciation. We investigate these dynamics in the most widely distributed of marine mammals, the killer whale (Orcinus orca), using a global data set of over 450 samples. This marine top predator inhabits coastal and pelagic ecosystems ranging from the ice edge to the tropics, often exhibiting ecological, behavioural and morphological variation suggestive of local adaptation accompanied by reproductive isolation. Results suggest a rapid global radiation occurred over the last 350 000 years. Based on habitat models, we estimated there was only a 15% global contraction of core suitable habitat during the last glacial maximum, and the resources appeared to sustain a constant global effective female population size throughout the Late Pleistocene. Reconstruction of the ancestral phylogeography highlighted the high mobility of this species, identifying 22 strongly supported long‐range dispersal events including interoceanic and interhemispheric movement. Despite this propensity for geographic dispersal, the increased sampling of this study uncovered very few potential examples of ancestral dispersal among ecotypes. Concordance of nuclear and mitochondrial data further confirms genetic cohesiveness, with little or no current gene flow among sympatric ecotypes. Taken as a whole, our data suggest that the glacial cycles influenced local populations in different ways, with no clear global pattern, but with secondary contact among lineages following long‐range dispersal as a potential mechanism driving ecological diversification.

A Bayesian Capture–Recapture Population Model With Simultaneous Estimation of Heterogeneity

We develop a Bayesian capture-recapture model that provides estimates of abundance as well as time-varying and heterogeneous survival and capture probability distributions. The model uses a state-space approach by incorporating an underlying population model and an observation model, and here is applied to photo-identification data to estimate trends in the abundance and survival of a population of bottlenose dolphins (Tursiops truncatus) in northeast Scotland. Novel features of the model include simultaneous estimation of time-varying survival and capture probability distributions, estimation of heterogeneity effects for survival and capture, use of separate data to inflate the number of identified animals to the total abundance, and integration of separate observations of the same animals from right and left side photographs. A Bayesian approach using Markov chain Monte Carlo methods allows for uncertainty in measurement and parameters, and simulations confirm the models validity.