Overwintering Physiology Of Arctic And Subarctic Insects From Interior Alaska

Thesis (Ph.D.) University of Alaska Fairbanks, 2009This dissertation focuses on the overwintering of three insects from Interior Alaska: a hemipteran, Elasmostethus interstinctus, and a coleopteran, Cucujus clavipes puniceus, that are freeze avoiding in the strict sense of the phrase, and a dipteran, Exechia nugatoria, that is simultaneously partially freeze avoiding and freeze tolerant. The variability within the freeze avoidance strategy itself is a key theme throughout this dissertation. Two significant contributions to comparative physiology are the confirmation of insect vitrification (glass formation) with its attendant extension of freeze avoidance and survival into a new, extreme low temperature record of -100�C and the simultaneous coupling of freeze avoidance and tolerance within an individual, which may more properly be described as a new overwintering strategy. Vitrification is the process by which ice crystallization is circumvented, resulting in a supercooled amorphous solid. Through a combination of antifreeze proteins that inhibit ice nucleation, dehydration tolerance, presence of high glycerol concentration, and low temperatures, the mobility of the remaining liquid water molecules is reduced, effectively by-passing the crystalline state. The second contribution is the discovery of a new overwintering strategy that combines freeze avoidance and freeze tolerance within an individual. In this case, the abdomen freezes (and the insect survives), while the contiguous head/thorax remains supercooled. These findings lead to the following evolutionary and trans-disciplinary questions. Is vitrification an adaptation? What is the selective advantage of compartmentalizing ice between body sections of an individual insect? Is this new overwintering strategy an example of a species transitioning between either becoming exclusively freeze avoiding or free tolerant? Applying new understanding of mechanisms of insect vitrification and avoidance of devitrification to cryomedicine may extend preservation of human tissues and organs. Similarly, for physical and material scientists, by understanding the patterns of ice formation within insects that tolerate, inhibit, and/or impede ice formation below the homogeneous ice nucleation temperature of water (-40�C), new biomimetic possibilities can be envisioned

Prevalence and Abundance of Cyamid “Whale Lice” (Cyamus ceti) on Subsistence Harvested Bowhead Whales (Balaena mysticetus)

We present findings on the prevalence and abundance of cyamid ectoparasites (Cyamus ceti) or “whale lice” on bowhead whales (Balaena mysticetus) harvested for subsistence in the Bering, Chukchi, and Beaufort Seas from 1973 to 2015. Cyamids were present on 20% of the 673 whales that were examined for cyamid ectoparasites. Logistic regression was used to determine factors associated with cyamid prevalence. The probability of cyamid presence increased with age, length, and improving body condition, but decreased over the past 35 years. Cyamid presence was also more probable on whales harvested in the spring than on those harvested in the fall. When present, cyamid abundance was typically low(< 10 per whale). Case histories provide ancillary information about the relationships between abundance of cyamids and their bowhead hosts. Environmental change and increasing anthropogenic disturbances are expected to occur in the Arctic regions inhabited by bowheads. We recommend continued monitoring of subsistence harvested whales for cyamids, as well as further investigations into the roles of environmental and anthropogenic variables in cyamid prevalence and abundance, as part of a comprehensive program of Arctic ecosystem assessment.Nous présentons nos constatations en matière de prévalence et d’abondance de l’ectoparasite cyamidae (Cyamus ceti) ou « pou des baleines » se trouvant sur la baleine boréale (Balaena mysticetus) capturée à des fins de subsistance dans la mer de Béring, la mer des Tchouktches et la mer de Beaufort entre 1973 et 2015. Les cyamidae étaient présents sur 20 % des 673 baleines qui ont été examinées dans le but d’y trouver des ectoparasites cyamidae. La régression logistique a servi à déterminer les facteurs liés à la prévalence de cyamidae. La probabilité de la présence de cyamidae augmentait en fonction de l’âge, de la longueur et de l’amélioration de l’état corporel, mais elle a diminué au cours des 35 dernières années. De plus, la présence de cyamidae était également plus probable chez les baleines capturées au printemps que chez les baleines capturées à l’automne. Lorsque présents, les cyamidae étaient généralement de faible abondance (< 10 par baleine). Les cas types fournissent des renseignements supplémentaires sur les relations entre l’abondance de cyamidae et les baleines hôtes. Des changements environnementaux et de plus grandes perturbations anthropiques sont attendus dans les régions arctiques où évolue la baleine boréale. Nous recommandons la surveillance continue des baleines attrapées à des fins de subsistance pour en détecter les cyamidae. Nous recommandons également des études plus approfondies afin de déterminer le rôle des variables environnementales et anthropiques en matière de prévalence et d’abondance des cyamidae, dans le cadre d’un programme exhaustif d’évaluation de l’écosystème arctique

Spectral reflectance of whale skin above the sea surface: a proposed measurement protocol

Great whales have been detected using very‐high‐resolution satellite imagery, suggesting this technology could be used to monitor whales in remote areas. However, the application of this method to whale studies is at an early developmental stage and several technical factors need to be addressed, including capacity for species differentiation and the maximum depth of detection in the water column. Both require knowledge of the spectral reflectance of the various whale species just above the sea surface, as when whales bodies break the surface of the water to breath, log or breach, there is, at times, no sea water between the whale's skin and the satellite sensor. Here we tested whether such reflectance could be measured on dead whale tissue. We measured the spectral reflectance of fresh integument collected during the bowhead subsistence harvest, and of thawed integument samples from various species obtained following strandings and stored at −20°C. We show that fresh and thawed samples of whale integument have different spectral properties. The reflectance of fresh samples was higher than the reflectance of thawed samples, as integument appears to darken after death and with time, even under frozen conditions. In this study, we present the first whale reflectance estimates (without the influence of sea water and for dead tissue). These provide a baseline for additional work, needed to advance the use of satellite imagery to monitor whales and facilitate their conservation

Pacific Salmon in the Rapidly Changing Arctic: Exploring Local Knowledge and Emerging Fisheries in Utqiaġvik and Nuiqsut, Alaska + Supplementary Appendix 1

One of the most pervasive signals of global climate change is altered patterns of distribution with trends towards poleward shifts of species. While habitat loss and destruction has severed connections between people and salmon in many locales, salmon fisheries in the high Arctic are just beginning to develop. To explore these emergent connections, we gathered local knowledge about Pacific salmon and emerging subsistence salmon fisheries in the Beaufort Sea region through ethnographic research in Utqiaġvik (formerly Barrow) and Nuiqsut, Alaska. Between 2010 and 2013, we interviewed 41 active fishermen and Elders who generally agreed that harvests of Pacific salmon species have been increasing in recent years, beginning in the 1990s and early 2000s. About 46% of active fishermen and Elders who discussed salmon abundance perceived an increasing trend over time. Another 43% characterized salmon abundance as cyclical or perceived no directional trend over time. The remaining fishermen (all from Nuiqsut) expressed their perception of decreasing salmon and fish abundance overall related to oil and gas development impacts to their local lands and waters. Given these mixed perceptions and harvests being an imperfect proxy for abundance, it remains unclear whether salmon populations are expanding in Arctic river systems. However, research participants have identified new stream systems not currently documented in the scientific literature where salmon are present and thought to be spawning. In both communities, we found that many fishermen and Elders often do not differentiate Pacific salmon species. Fishermen in both communities are developing new knowledge of salmon and increasing their use of salmon as a subsistence resource, yet uncertainties in the current data and local knowledge combine to generate equivocal evidence that salmon abundance is increasing. This lack of a clear increase in salmon abundance provides nuance to a simple story that warming has led to the increases of salmon in the Arctic. Despite the uncertainty regarding abundance, it is clear we are witnessing an emergence of new salmon fisheries in the high Arctic, perceived to be one among a suite of environmental and social changes currently being experienced in this region.Un des signes les plus omniprésents du changement climatique à l’échelle mondiale se voit dans les modèles de répartition modifiés, les espèces affichant des tendances de déplacement vers les pôles. Même si la perte et la destruction d’habitats ont coupé les liens entre la population et le saumon en maints endroits, les pêcheries de saumon de l’Extrême- Arctique ne font que commencer à se développer. Afin d’explorer ces liens émergents, nous avons recueilli des connaissances locales au sujet du saumon du Pacifique dans la région de la mer de Beaufort par le biais d’une recherche ethnographique à Utqiaġvik (anciennement Barrow) et à Nuiqsut, en Alaska. Entre 2010 et 2013, nous avons interrogé 41 pêcheurs actifs et aînés, qui s’entendaient généralement pour dire que les récoltes d’espèces de saumon du Pacifique ont augmenté ces dernières années, plus précisément depuis les années 1990 et le début des années 2000. Environ 46 % des pêcheurs actifs et des aînés qui se sont entretenus de l’abondance du saumon avaient perçu une tendance à la hausse au fil des ans, tandis que 43 % d’entre eux estimaient que l’abondance du saumon était cyclique, ou encore, qu’elle n’affichait aucune tendance directionnelle avec le temps. Les autres pêcheurs (tous de Nuiqsut) ont déclaré que dans l’ensemble, ils avaient l’impression que l’abondance de saumon et d’autres poissons diminuait en raison des incidences de la mise en valeur du pétrole et du gaz sur les terres et les cours d’eau de leur région. Compte tenu de ces perceptions mitigées et du fait que les récoltes ne constituent pas de bons témoins de l’abondance, il n’est toujours pas clair si les populations de saumon augmentent ou non dans les réseaux fluviaux de l’Arctique. Cependant, les participants à la recherche ont indiqué que de nouveaux réseaux hydrographiques non documentés dans les publications scientifiques comptent du saumon et que celui-ci semble frayer. Dans les deux collectivités, nous avons trouvé que de nombreux pêcheurs et aînés ne font souvent pas la différence entre les espèces de saumon du Pacifique. Les pêcheurs des deux collectivités acquièrent de nouvelles connaissances au sujet du saumon et intensifient leur usage du saumon comme ressource de subsistance. Cela dit, les incertitudes entourant les données actuelles et les connaissances locales s’allient pour prouver de manière équivoque que l’abondance du saumon augmente. L’absence de preuves claires en ce qui a trait à l’abondance du saumon vient nuancer une histoire simple selon laquelle le réchauffement se traduit par l’augmentation du saumon dans l’Arctique. Malgré l’incertitude concernant l’abondance, il est clair que nous sommes témoins d’une émergence de nouvelles pêcheries de saumon dans l’Extrême-Arctique. Cette émergence est perçue comme faisant partie d’un éventail de changements environnementaux et sociaux se manifestant dans cette région

Data from: How do baleen whales stow their filter? A comparative biomechanical analysis of baleen bending

Bowhead and right whale (balaenid) baleen filtering plates, longer in vertical dimension (3-4+ m) than the closed mouth, presumably bend during gape closure. This has not been observed in live whales, even with scrutiny of videorecorded feeding sequences. To determine what happens to baleen as gape closes, we conducted an integrative, multifactorial study including materials testing, functional (flow tank and kinematic) testing, and histological examination. We measured baleen bending properties along the dorsoventral length of plates and anteroposterior location within a rack of plates via mechanical (axial bending, composite flexure, compression, and tension) tests of hydrated and air-dried tissue samples from balaenid and other whale baleen. Balaenid baleen is remarkably strong yet pliable, with ductile fringes and low stiffness and high elasticity when wet; it likely bends in the closed mouth when not used for filtration. Calculation of flexural modulus from stress/strain experiments shows baleen is slightly more flexible where it emerges from the gums and at its ventral terminus, but kinematic analysis indicates plates bend evenly along their whole length. Fin and humpback whale baleen has similar material properties but less flexibility, with no dorsoventral variation. Internal horn tubes have greater external and hollow luminal diameter but lower density in lateral relative to medial baleen of bowhead and fin whales, suggesting greater capacity for lateral bending. Baleen bending has major consequences not only for feeding morphology and energetics but also conservation given that entanglement in fishing gear is a leading cause of whale mortality

baleen bending database

Raw data for all parts of this investigatio

Supplemental File 4 weights from Hydration affects the physical and mechanical properties of baleen tissue

Baleen, an anisotropic oral filtering tissue found only in the mouth of mysticete whales and made solely of alpha-keratin, exhibits markedly differing physical and mechanical properties between dried or (as in life) hydrated states. On average baleen is 32.35% water by weight in North Atlantic right whales (<i>Eubalaena glacialis</i>) and 34.37% in bowhead whales (<i>Balaena mysticetus</i>). Baleen's wettability measured by water droplet contact angles shows that dried baleen is hydrophobic whereas hydrated baleen is highly hydrophilic. Three-point flexural bending tests of mechanical strength reveal that baleen is strong yet ductile. Dried baleen is brittle and shatters at about 20-30 N mm^-2 but hydrated baleen is less stiff; it bends with little force and absorbed water is squeezed out when force is applied. Maximum recorded stress was 4 times higher in dried (mean 14.29 N mm^-2) versus hydrated (mean 3.69 N mm^-2) baleen, and the flexural stiffness was >10 times higher in dried (mean 633 N mm^-2) versus hydrated (mean 58 N mm^-2) baleen. In addition to documenting hydration's powerful effects on baleen, this study indicates that baleen is far more pliant and malleable than commonly supposed, with implications for studies of baleen's structure and function as well as its susceptibility to oil or other hydrophobic pollutants

Supplemental File 1 converted original test data from Hydration affects the physical and mechanical properties of baleen tissue

Baleen, an anisotropic oral filtering tissue found only in the mouth of mysticete whales and made solely of alpha-keratin, exhibits markedly differing physical and mechanical properties between dried or (as in life) hydrated states. On average baleen is 32.35% water by weight in North Atlantic right whales (<i>Eubalaena glacialis</i>) and 34.37% in bowhead whales (<i>Balaena mysticetus</i>). Baleen's wettability measured by water droplet contact angles shows that dried baleen is hydrophobic whereas hydrated baleen is highly hydrophilic. Three-point flexural bending tests of mechanical strength reveal that baleen is strong yet ductile. Dried baleen is brittle and shatters at about 20-30 N mm^-2 but hydrated baleen is less stiff; it bends with little force and absorbed water is squeezed out when force is applied. Maximum recorded stress was 4 times higher in dried (mean 14.29 N mm^-2) versus hydrated (mean 3.69 N mm^-2) baleen, and the flexural stiffness was >10 times higher in dried (mean 633 N mm^-2) versus hydrated (mean 58 N mm^-2) baleen. In addition to documenting hydration's powerful effects on baleen, this study indicates that baleen is far more pliant and malleable than commonly supposed, with implications for studies of baleen's structure and function as well as its susceptibility to oil or other hydrophobic pollutants

Supplemental File 3 data plots from Hydration affects the physical and mechanical properties of baleen tissue

Baleen, an anisotropic oral filtering tissue found only in the mouth of mysticete whales and made solely of alpha-keratin, exhibits markedly differing physical and mechanical properties between dried or (as in life) hydrated states. On average baleen is 32.35% water by weight in North Atlantic right whales (<i>Eubalaena glacialis</i>) and 34.37% in bowhead whales (<i>Balaena mysticetus</i>). Baleen's wettability measured by water droplet contact angles shows that dried baleen is hydrophobic whereas hydrated baleen is highly hydrophilic. Three-point flexural bending tests of mechanical strength reveal that baleen is strong yet ductile. Dried baleen is brittle and shatters at about 20-30 N mm^-2 but hydrated baleen is less stiff; it bends with little force and absorbed water is squeezed out when force is applied. Maximum recorded stress was 4 times higher in dried (mean 14.29 N mm^-2) versus hydrated (mean 3.69 N mm^-2) baleen, and the flexural stiffness was >10 times higher in dried (mean 633 N mm^-2) versus hydrated (mean 58 N mm^-2) baleen. In addition to documenting hydration's powerful effects on baleen, this study indicates that baleen is far more pliant and malleable than commonly supposed, with implications for studies of baleen's structure and function as well as its susceptibility to oil or other hydrophobic pollutants

Reproductive parameters of Bering‐Chukchi‐Beaufort Seas bowhead whales

Data from Bering-Chukchi-Beaufort Seas bowhead whales (Balaena mysticetus), harvested during 1973–2021 by aboriginal subsistence hunters, were used to estimate reproductive parameters: length at sexual maturity (LSM), age at sexual maturity (ASM), pregnancy rate (PR), and calving interval. Sexual maturity (N&nbsp;=&nbsp;187 females) was determined from the presence/absence of corpora in the ovaries, or a fetus. Using sampling bias-corrected logistic regression, LSM was estimated at 13.5 m, 95% CI [13.0, 13.8]. There was a downward trend in LSM over time, statistically significant with one method but marginal with another. A growth model translated this estimate to an ASM estimate of 23.5 years, 95% CI [20.4, 26.7]. Pregnancy rate was determined from mature females (N&nbsp;=&nbsp;125), and from a subset limited to certain autumn-caught whales (n&nbsp;=&nbsp;37) to reduce bias. The PR was estimated at 0.46 globally, 95% CI [0.36, 0.55] and 0.38 for the autumn sample, 95% CI [0.20, 0.51]. Both estimated PRs are consistent with a 3-year calving interval, because the larger estimate includes two cohorts of pregnant whales harvested in spring, and bowhead whale gestation is longer than 12 months. These analyses represent the most conclusive empirical estimates of ASM, LSM, and PR for this bowhead whale stock from the largest available data sets to date