Validation of a blubber-based endocrine pregnancy test for humpback whales

Baleen whales have few identifiable external indicators of pregnancy state, making it challenging to study essential aspects of their biology and population dynamics. Pregnancy status in other marine mammals has been determined by measuring progesterone concentrations from a variety of sample matrices, but logistical constraints have limited such studies in free-swimming baleen whales. We use an extensive blubber sample archive and associated calving history data to retrospectively identify samples that correspond to pregnant females and develop a progesterone-based pregnancy test for humpback whales. The lowest pregnant blubber progesterone concentration was 54.97 ng g−1, and the mean for the known-pregnant group was 198.74 ± 180.65 ng g−1. Conversely, females known to be below the minimum age of sexual maturity (juvenile females) had an overall low mean progesterone concentration (0.59 ± 0.25 ng g−1), well below the known-pregnant range. Of the mature females that did not return with a calf (n = 11), three fell within the known-pregnant range (320.79 ± 209.34 ng g−1), while the levels for the remaining eight were two orders of magnitude below the lowest known-pregnant level (1.63 ± 1.15 ng g−1). The proportion of females that did not return with a calf but had values similar to known-pregnant females are consistent with rates of calf mortality, but other potential explanations were considered. Our findings support a validated blubber endocrine assignment of pregnancy corroborated with field life history information, a first for any baleen whale species. The progesterone values we measured were similar to those found in different pregnancy states of other cetaceans and support using blubber biopsy samples for assigning pregnancy in humpback whales. This method can be applied to existing archives or new samples to better study life history and population demography broadly across species and populations

PHFinder: Assisted detection of point heteroplasmy in Sanger sequencing chromatograms

Heteroplasmy is the presence of two or more organellar genomes (mitochondrial or plastid DNA) in an organism, tissue, cell or organelle. Heteroplasmy can be detected by visual inspection of Sanger sequencing chromatograms, where it appears as multiple peaks of fluorescence at a single nucleotide position. Visual inspection of chromatograms is both consuming and highly subjective, as heteroplasmy is difficult to differentiate from background noise. Few software solutions are available to automate the detection of point heteroplasmies, and those that are available are typically proprietary, lack customization or are unsuitable for automated heteroplasmy assessment in large datasets. Here, we present PHFinder, a Python-based, open source tool to assist in the detection of point heteroplasmies in large numbers of Sanger chromatograms. PHFinder automatically identifies point heteroplasmies directly from the chromatogram trace data. The program was tested with Sanger sequencing data from 100 humpback whale (Megaptera novaeangliae) tissue samples with known heteroplasmies. PHFinder detected most (90%) of the known heteroplasmies thereby greatly reducing the amount of visual inspection required. PHFinder is flexible, enabling explicit specification of key parameters to infer double peaks (i.e., heteroplasmies)

Individual and population dietary specialization decline in fin whales during a period of ecosystem shift

Abstract This study sought to estimate the effect of an anthropogenic and climate-driven change in prey availability on the degree of individual and population specialization of a large marine predator, the fin whale (Balaenoptera physalus). We examined skin biopsies from 99 fin whales sampled in the St. Lawrence Estuary (Canada) over a nine year period (1998–2006) during which environmental change was documented. We analyzed stable isotope ratios in skin and fatty acid signatures in blubber samples of whales, as well as in seven potential prey species, and diet was quantitatively assessed using Bayesian isotopic models. An abrupt change in fin whale dietary niche coincided with a decrease in biomass of their predominant prey, Arctic krill (Thysanoessa spp.). This dietary niche widening toward generalist diets occurred in nearly 60% of sampled individuals. The fin whale population, typically composed of specialists of either krill or lipid-rich pelagic fishes, shifted toward one composed either of krill specialists or true generalists feeding on various zooplankton and fish prey. This change likely reduced intraspecific competition. In the context of the current “Atlantification” of northern water masses, our findings emphasize the importance of considering individual-specific foraging tactics and not only population or group average responses when assessing population resilience or when implementing conservation measures

A first record of Pestalotiopsis clavispora in Argan mass cutting propagation: Prevalence, prevention and consequences for plant production

A trial involving the mass propagation of Argania spinosa cuttings was established following two protocols: in mini-bouturathèques without mist and in a greenhouse under mist. Symptoms of petiole necrosis, foliar yellowing and abundant black acervuli were observed under both protocols. These symptoms were responsible for a 90% mortality rate in the mini-bouturathèques while under the mist treatment premature fatal necrosis of the apical buds resulted in 100% mortality. The disease’s causal agent, Pestalotiopsis clavispora, was identified on the basis of its morphological characteristics and by molecular analysis. Alternating weekly treatments of systemic and contact fungicides resulted in a 41% success rate in controlling this pathogen, described for the first time on argan cuttings.Deux approches différentes de bouturage de masse d’Argania spinosa ont été utilisées. La première consistait à enraciner les boutures dans des mini-bouturathèques sans brumisation, tandis que la deuxième consistait à utiliser une serre dotée d’un brumisateur. Des symptômes de nécrose des pétioles et de jaunissement des feuilles ainsi qu’une production abondante d’acervules noires ont été observés dans les deux protocoles. Dans les mini-bouturathèques, ces symptômes ont entraîné un taux de mortalité de 90 % des boutures, alors que sous brumisateur la nécrose précoce et fatale des bourgeons apicaux a engendré 100 % de mortalité. L’agent causal de la maladie, Pestalotiopsis clavispora, décrit pour la première fois sur les boutures d’arganier, a été identifié à partir de ses caractères morphologiques et par analyse moléculaire. Un traitement hebdomadaire à base de fongicide systémique et de fongicide de contact utilisés en alternance a permis de maîtriser cet agent pathogène avec un taux de réussite de 41 %

Examining the Skill Gap in Fashion Education

This research explores the importance of sewing skills within HE fashion education. Recent literature has identified significant discussion concerning a graduate skills gap at the onset of employment. Some industry specialists fear that educators are not doing enough to promote the technical side of fashion. As a consequence, there are concerns of a widening gap in the uptake of technical job roles within the fashion sector. This research investigates potential reasons why students might not make these career choices, focusing mainly on the teaching of construction skills through the development of a resource tool to enhance the curriculum to bridge this recognised gap. To contextualise the development of this project, literature has examined key areas of interest. These include studies relating to skill gaps, manufacture and production techniques as well as the relationship between technical skill and career interests. This research has applied a variety of methodologies, which have explored the skills required for fundamental sewing processes, the value of sewing from educational and industry perspectives and issues relating to the recognised skills gap and career choices. Methods have included object-based study, interviews with manufacturers and a focus group with second year BA (Hons) fashion design students undertaking pattern cutting and manufacture sessions. To evaluate the effectiveness of the resource tool of stitch and garment finishing techniques, questionnaires, observations and examinations were conducted with undergraduate students undertaking sewing sessions. This research has revealed that the resource tool was successful in engaging students with garment construction techniques, and that this was most beneficial when used in conjunction with other methods. During testing it was apparent that students preferred to work more creatively, using inventiveness over memory of previously taught sewing skills when producing samples. Interestingly, the research has also highlighted two distinctions; that further technical knowledge in sewing appears to, in some instances, have limited the creativity of students’ fashion design outcomes when advancing from a foundation to intermediate level of study. However, there is also evidence to suggest that further engagement with sewing had a positive influence on their understanding of garment construction informing feasible design. There appears to be minimal evidence that links strong sewing skill with the ambition to choose careers in the manufacturing sector. The conclusions from this research, including the testing results from the resource tool, support the development of a technical curriculum within the BA curriculum, and the development of a qualification level prior to BA

Fin whale survival and abundance in the Gulf of St. Lawrence, Canada

The fin whale Balaenoptera physalus, the second largest species in the animal kingdom to have lived on Earth, was heavily targeted during the industrial whaling era. North Atlantic whaling for this species ended in 1987 and it is unclear if the populations are recovering. The stock structure in the North Atlantic is still under debate, but several lines of evidence suggest that fin whales in the Gulf of St. Lawrence may form a discrete stock with limited exchange with the rest of the North Atlantic. We applied mark-recapture models to 21 yr of photo-identification data from the Jacques-Cartier Passage to estimate the abundance and, for the first time, a survival rate based on live re-sightings for this stock of fin whales. Using the Cormack-Jolly-Seber model, we estimated a unisex non-calf apparent survival rate of 0.955 (95% CI: 0.936 to 0.969) for the period 1990 to 2010, declining in the last 4 yr of the study. The reduced survivorship was likely caused by a lower site fidelity combined with a higher mortality. The POPAN model yielded a super-population estimate of 328 individuals (95% CI: 306 to 350) for the period 2004 to 2010, and confirmed the negative trend in apparent survival and annual abundance, indicating that the population has not increased since the last large-scale surveys from 1974 and 1997.Publisher PDFPeer reviewe

Utility of telomere length measurements for age determination of humpback whales

This study examines the applicability of telomere length measurements by quantitative PCR as a tool for minimally invasive age determination of free-ranging cetaceans. We analysed telomere length in skin samples from 28 North Atlantic humpback whales (Megaptera novaeangliae), ranging from 0 to 26 years of age. The results suggested a significant correlation between telomere length and age in humpback whales. However, telomere length was highly variable among individuals of similar age, suggesting that telomere length measured by quantitative PCR is an imprecise determinant of age in humpback whales. The observed variation in individual telomere length was found to be a function of both experimental and biological variability, with the latter perhaps reflecting patterns of inheritance, resource allocation trade-offs, and stochasticity of the marine environment

The population genomic structure of green turtles (<i>Chelonia mydas</i>) suggests a warm-water corridor for tropical marine fauna between the Atlantic and Indian oceans during the last interglacial

The occasional westward transport of warm water of the Agulhas Current, “Agulhas leakage”, around southern Africa has been suggested to facilitate tropical marine connectivity between the Atlantic and Indian oceans, but the “Agulhas leakage” hypothesis does not explain the signatures of eastward gene flow observed in many tropical marine fauna. We investigated an alternative hypothesis: the establishment of a warm-water corridor during comparatively warm interglacial periods. The “warm-water corridor” hypothesis was investigated by studying the population genomic structure of Atlantic and Southwest Indian Ocean green turtles (N = 27) using 12,035 genome-wide single nucleotide polymorphisms (SNPs) obtained via ddRAD sequencing. Model-based and multivariate clustering suggested a hierarchical population structure with two main Atlantic and Southwest Indian Ocean clusters, and a Caribbean and East Atlantic sub-cluster nested within the Atlantic cluster. Coalescent-based model selection supported a model where Southwest Indian Ocean and Caribbean populations diverged from the East Atlantic population during the transition from the last interglacial period (130–115 thousand years ago; kya) to the last glacial period (115–90 kya). The onset of the last glaciation appeared to isolate Atlantic and Southwest Indian Ocean green turtles into three refugia, which subsequently came into secondary contact in the Caribbean and Southwest Indian Ocean when global temperatures increased after the Last Glacial Maximum. Our findings support the establishment of a warm-water corridor facilitating tropical marine connectivity between the Atlantic and Southwest Indian Ocean during warm interglacials

A genetic perspective on cetacean evolution

Studies of cetacean evolution using genetics and other biomolecules have come a long way—from the use of allozymes and short sequences of mitochondrial or nuclear DNA to the assembly of full nuclear genomes and characterization of proteins and lipids. Cetacean research has also advanced from using only contemporary samples to analyzing samples dating back thousands of years, and to retrieving data from indirect environmental sources, including water or sediments. Combined, these studies have profoundly deepened our understanding of the origin of cetaceans; their adaptation and speciation processes; and of the past population change, migration, and admixture events that gave rise to the diversity of cetaceans found today