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Abstract Previous studies on PCDD/Fs and PCBs in dugong (Dugong dugon) blubber reported unexpectedly elevated TEQ levels. This study analysed archived blubber, muscle, liver and faeces obtained from dugongs from two areas along the Queensland coast. All samples showed detectable levels of PCDDs and PCBs, while PCDFs were consistently near or below LOQ. PCDD levels in dugongs contributed to a large proportion (<95%) of sum TEQ levels in all tissues (blubber: 6.7–38 pg g−1 lw, muscle: 5.7–96 pg g−1 lw, liver: 3.3–42 pg g−1 lw, faeces: 203 pg g−1 lw). Liver/blubber tissue ratios show that PCDDs are preferentially accumulated in the liver with higher degree of chlorination. The same trend was not so obvious with PCBs, which occasionally showed higher hepatic sequestration of lower chlorinated PCBs such as PCBs 28 and 77. PCDD congeners were dominated by OCDD which is similar to the profiles from the dugongs' food source, namely sediment and seagrass. Highlights • Study analysed different dugong tissues from two locations on the Queensland coast. • PCDD/Fs levels were lower than PCBs but contributed up to 95% to the TEQ levels. • PCDD congeners were dominated by higher chlorinated PCDDs in particular OCDD. • Higher PCDD and PCB levels in dugongs from SEQ suggest exposure may have increased. • Higher chlorinated PCDDs accumulated preferentially in the liver than in blubber. [ABSTRACT FROM AUTHOR]

This article explores the history of the Russian monopolistic companies that operated in the international market for blubber in the first half of the eighteenth century. It argues that the long-held view that the companies were unsuccessful is not supported by the statistics relating to the trade, which indicate impressive progress in terms of market revenue and the redistribution of profits. Moreover, the authorities had ambitious strategic goals for the project as a whole that entailed more than simple commercial success. The companies, in fact, were perceived as an instrument that would transform landlocked Muscovy into a leading power in the international maritime economy. The article analyzes the essence and the consequences of these conflicting perspectives. [ABSTRACT FROM AUTHOR]

Abstract Individuals store energy to balance deficits in natural cycles; however, unnatural events can also lead to unbalanced energy budgets. Entanglement in fishing gear is one example of an unnatural but relatively common circumstance that imposes energetic demands of a similar order of magnitude and duration of life‐history events such as migration and pregnancy in large whales. We present two complementary bioenergetic approaches to estimate the energy associated with entanglement in North Atlantic right whales, and compare these estimates to the natural energetic life history of individual whales. Differences in measured blubber thicknesses and estimated blubber volumes between normal and entangled, emaciated whales indicate between 7.4 × 1010 J and 1.2 × 1011 J of energy are consumed during the course to death of a lethal entanglement. Increased thrust power requirements to overcome drag forces suggest that when entangled, whales require 3.95 × 109 to 4.08 × 1010 J more energy to swim. Individuals who died from their entanglements performed significantly more work (energy expenditure × time) than those that survived; entanglement duration is therefore critical in determining whales’ survival. Significant sublethal energetic impacts also occur, especially in reproductive females. Drag from fishing gear contributes up to 8% of the 4‐year female reproductive energy budget, delaying time of energetic equilibrium (to restore energy lost by a particular entanglement) for reproduction by months to years. In certain populations, chronic entanglement in fishing gear can be viewed as a costly unnatural life‐history stage, rather than a rare or short‐term incident.

To date, only limited results on the fatty composition in different tissues of the top predators in the Baltic Sea are available. In the current study, tissue samples of blubber, skeletal muscle, and liver from 8 harbour porpoise (Phocoena phocoena) and 17 grey seals (Halichoerus grypus) in the Baltic Sea off Mecklenburg-Western Pomerania were included in the investigation. While the total fatty acid content in liver and blubber tissue revealed no differences between both species, the total fatty acid content of muscle tissue was significantly differentand showed higher concentrations in harbour porpoise muscle compared with grey seals. The most abundant fatty acids in the blubber of grey seals and harbour porpoises (18:1cis-9, 16:1cis-9, 16:0 and 22:6n-3) were present in similar quantities and ratios to each other as known from other marine top predators. If future studies can show that differences in tissue fatty acid content are caused by variation in the nutritional status, and this may lead to the development of a more objective assessment of body condition in seals and porpoises recovered via stranding schemes.

Animals with large adipose stores, such as marine mammals, may provide insights into the evolution and function of this multifunctional tissue in health and disease. In the absence of sequenced genomes, molecular information can be rapidly obtained by proteomics and transcriptomics, but their application to adipose tissue is hindered by low nucleic acid and protein yields. We sequenced and compared proteomes isolated from the blubber of four elephant seals using phenol and guanidine thiocyanate (Qiazol) or detergent (sodium deoxycholate) buffer. Qiazol recovered more subcellular proteins such as metabolic enzymes, in addition to extracting RNA, facilitating proteogenomic analyses of small lipid-rich tissue biopsies. We also compared proteomics data analysis platforms and found that de novo peptide sequencing improved protein identification sensitivity compared to database search alone. We report sample preparation and data analysis workflows for proteogenomics and a proteome of elephant seal blubber containing 2678 proteins, including many of interest for further functional studies. This article has an associated First Person interview with the first author of the paper.

Highlights • Analyzed samples of Native Alaskan fish, land and marine mammals (meat and oils/fats) • Vitamin D 3 , 25-hydroxy-vitamin D3, vitamin D2 analyzed by LC–MS • >15 μg D 3 /100 g: beluga whale skin, fat; seal oil; salmon; dried fish; sheefish eggs • >0.6 μg 25(OH)D 3 /100 g: smoked salmon; beluga whale skin, fat; whale, spotted seal oil • Potential seasonal variation in vitamin D content between and within species of marine mammals Abstract Greater consumption of traditional foods has been associated with improved vitamin D status in Arctic and sub-Arctic populations, including Alaskan Native Americans. However, lack of vitamin D food composition data impairs epidemiological studies on health outcomes, and development of specific dietary recommendations. Vitamin D, including 25(OH)D 3 was quantified in samples of native fish, fish eggs, meats (caribou, goose, whale, seal) and traditionally prepared whale and seal oil collected from Alaskan tribes. Vitamin D 3 , 25(OH)D 3 , and vitamin D 2 were assayed in alkaline-saponified samples by UPLC-MS, after derivatization with 4-phenyl-1,2,4-triazole-3,5-dione, with in-house control materials and/or NIST SRM® 1546a Meat Homogenate included in each analytical batch. All but the land animals and bearded seal meat contained ≥2 μg vitamin D 3 /100 g, with >10 μg/100 g in steelhead trout; dried sheefish, whitefish, smelt; smoked/dried salmon; fermented sheefish eggs; whale and seal oils. Large between-sample differences in bearded seal oil suggested possible effects of season and/or maturity on vitamin D content. 25(OH)D 3 was >0.3 μg/100 g in many foods, notably smoked salmon, beluga whale skin/fat and oil and spotted seal (but not other seal) oil, with the highest levels in dried beluga whale meat, skin/fat, and oil (up to 1.2). Vitamin D 2 was <0.2 μg/100 g in all foods. [ABSTRACT FROM AUTHOR]

Killer whales (Orcinus orca) are among the most highly polychlorinated biphenyl (PCB)–contaminated mammals in the world, raising concern about the health consequences of current PCB exposures. Using an individual-based model framework and globally available data on PCB concentrations in killer whale tissues, we show that PCB-mediated effects on reproduction and immune function threaten the long-term viability of >50% of the world’s killer whale populations. PCB-mediated effects over the coming 100 years predicted that killer whale populations near industrialized regions, and those feeding at high trophic levels regardless of location, are at high risk of population collapse. Despite a near-global ban of PCBs more than 30 years ago, the world’s killer whales illustrate the troubling persistence of this chemical class. [ABSTRACT FROM AUTHOR]

A booming whale-watching industry in Juneau, Alaska, is raising concerns over potential impacts to humpback whales (Megaptera novaeangliae) and the sustainability of this growing industry. In this study, we investigated the physiological response of these whales to chronic vessel disturbance by measuring hormone concentrations (cortisol, progesterone, testosterone, and estradiol) that have been sequestered in blubber throughout the whale-watching season. We focused our analysis on cortisol, a steroid hormone associated with stress response, and hypothesized that cortisol in biopsy samples would be positively correlated with the amount of vessel traffic in the 3 to 4 months prior to sampling. Humpback whales in the Juneau area were compared with whales from control areas with far less vessel traffic in both Southeast Alaska and the western Gulf of Alaska using biopsies collected late in the tour season. We did not find elevated cortisol in whales sampled in the Juneau area relative to the Southeast Alaska control area (p = 0.14) or sites in the western Gulf of Alaska, which had higher cortisol levels (p < 0.001). The cause of the regional cortisol differences is not known but could be representative of regional differences in baseline hormone concentrations or be linked to predator or nutritional stressors. The lack of elevated cortisol in Juneau-area whales suggests high vessel traffic is not resulting in chronic cortisol sequestration in whales and may be indicative of whales near Juneau being habituated to vessel traffic. [ABSTRACT FROM AUTHOR]

Perfluorinated alkyl acids (PFAAs) have been used for 50 + years in materials such as stain-resistant treatments for paper and clothing, lubricants, and foam fire extinguishers. PFAAs are characterized by a fully fluorinated alkyl chain with a terminal acid group. Their long half-lives and ubiquitous environmental distribution create considerable concern for wildlife and human exposure. There is interest in examining temporal trends of PFAAs using the National Marine Mammal Tissue Bank (NMMTB), but NMMTB tissues are frozen and cryohomogenized in polytetrafluoroethylene (PTFE)-based materials. Because PTFE supplies may leach PFAAs into samples, this study mimicked collection, processing and storage steps of NMMTB samples and measured PFAA leaching to determine the feasibility of using this sample archive for PFAA temporal trends. We also explored concentrations in Atlantic white-sided dolphin ( Lagenorhynchus acutus , WSDs) and rough-toothed dolphin ( Steno bredanensis , RTDs) blubber ( n = 3 and 0) and liver ( n = 48 and 12, respectively). The materials used in NMMTB protocols may add up to 0.968 ng/g perfluorooctanoic acid (PFOA), 0.090 ng/g perfluorononanoic acid (PNFA), and 0.221 ng/g perfluorooctane sulfonate (PFOS) to each archived sample. Leaching of PFNA and PFOS from supplies compared to dolphin levels was negligible, but PFOA contributions were substantially higher than levels found in most dolphin liver samples. Therefore, monitoring PFOA temporal trends from the NMMTB would require careful consideration. RTDs had significantly higher levels of PFOS and PFNA than WSDs. Both species have similar life history, trophic status, and foraging behaviors in deep pelagic waters, so differences could be from latitudinal variation in contamination. RTDs stranded in Florida; WSDs stranded farther north mostly in Massachusetts. Juveniles had significantly higher levels of PFOS and PFNA than adults in both species, suggesting growth dilution as they approach maturity. PFOS significantly decreased after 2001 in both species as expected based on changes in production. [ABSTRACT FROM AUTHOR]

The Odontocetes (toothed whales) possess two types of specialized fat and, therefore, represent an interesting group when considering the evolution and function of adipose tissue. All whales have a layer of superficial blubber, which insulates and streamlines, provides buoyancy and acts as an energy reserve. Some toothed whales deposit large amounts of wax esters, rather than triacylglycerols, in blubber, which is unusual. Waxes have very different physical and physiological properties, which may impact blubber function. The cranial acoustic fat depots serve to focus sound during echolocation and hearing. The acoustic fats have unique morphologies; however, they are even more specialized biochemically because they are composed of a mix of endogenous waxes and triacylglycerols with unusual branched elements (derived from amino acids) that are not present in other mammals. Both waxes and branched elements alter how sound travels through a fat body; they are arranged in a 3D topographical pattern to focus sound. Furthermore, the specific branched-chain acid/alcohol synthesis mechanisms and products vary phylogenetically (e.g. dolphins synthesize lipids from leucine whereas beaked whales use valine). I propose that these specialized lipids evolved first in the head: wax synthesis first emerged to serve an acoustic function in toothed whales, with branched-chain synthesis adding additional acoustic focusing power, and some species secondarily retained wax synthesis pathways for blubber. Further research is necessary to elucidate specific molecular mechanisms controlling the synthesis and deposition of wax esters and branched-chain fatty acids, as well as their spatial deposition within tissues and within adipocytes. [ABSTRACT FROM AUTHOR]

This work is focused on the chemical characterization of the organic residues preserved in ceramic fragments that are suspected to have been used by the Basque whalers in the period from 16th to 17th Century to store whale oil. The lipid profiling along with the identification of biomolecular markers, makes possible to obtain information on the contents of the vessels and on the transformations undergone by the organic substances during the burial process. To achieve this goal, two complementary analytical techniques, High-Performance Liquid Chromatography - Electrospray Ionization - Quadrupole Time-of-Flight Mass Spectrometry (HPLC-ESI-QToF) and Gas Chromatography-Mass Spectrometry (GC–MS), were used not only to study the archaeological materials but also fresh whale oil products used as reference materials with the aim to detect potential diagnostic biomarkers. HPLC-ESI-QToF was used to identify triacylglycerols (TAGs) and study their distribution in the various samples, whereas GC–MS after suitable derivatization provided the fatty acid (FA) profile together with the detection of degradation compounds (dicarboxylic and dihydroxy fatty acids) and biomarkers related to marine commodities (isoprenoid acids). Samples of blubber from 5 different whale species belonging to the genus Balaenoptera (fin, sei and minke whale), Megaptera (Humpback whale) and Phocoena (harbour porpoise) were used as reference materials together with a sample of whale oil of unknown origin. The chemical results confirm the archaeological data regarding the vessels use as containers to store whale oil and indicate the whales from Balaenoptera genus as the most probable source of the oil. [ABSTRACT FROM AUTHOR]

The skin and blubber of marine mammals provides protection from the surrounding environment, whether that be temperature, microbes, or direct mechanical impacts. To understand the ability of harbor seals’ ( Phoca vitulina) skin and blubber to resist blunt force trauma, we tested the material properties of these tissues. We quantified two mechanical properties of the tissue: tensile strength and tensile stiffness, at two test speeds, three sample orientations, and two age groups. We found significant differences in material properties between test speeds, orientation, and age of the animal, but did not find a large difference with orientation. From this analysis, we conclude that harbor seal skin and blubber should be modeled as an isotropic non-linear elastic material with strain rate dependence. Moreover, we were interested in the effects of freezing on the biomechanical properties. The material was tested fresh and after being frozen for four months. Frozen data revealed an increase in stiffness and strength for the skin (epidermis and dermis), but did not show a conclusive trend in the blubber material properties. While the availability of frozen marine mammal tissue is greater than that of fresh material, frozen tissue of harbor seals, especially the skin, cannot serve as an accurate replacement for testing of fresh material. [ABSTRACT FROM AUTHOR]

Marine mammals consume large quantities of microplastic particles, likely via trophic transfer (i.e., through prey who have consumed plastic) and direct consumption from seawater or sediment. Microplastics have been found in the stomachs, gastro-intestinal tracts, and feces of cetaceans and pinnipeds. Translocation of ingested microplastics has been documented in other organs of several aquatic species, but has not been examined in marine mammals. Marine mammals have highly specialized lipid-rich tissues which may increase susceptibility to lipophilic microplastics. Here we demonstrate the occurrence of microplastics, ranging in size, mass concentration, and particle count concentration from 24.4 μm – 1387 μm, 0.59 μg/g – 25.20 μg/g, and 0.04 – 0.39 particles/g, respectively, in four tissues (acoustic fat pad, blubber, lung, & melon) from twelve marine mammal species inclusive of mysticetes, odontocetes, and phocids. Twenty-two individuals were examined for microplastics using a combination of Raman spectroscopy and pyrolysis gas chromatography with mass spectrometry. Overall, 68% of individuals had at least one microplastic particle in at least one of the four tissue types, with the most common polymer and shape observed being polyethylene and fibers, respectively. These findings suggest some proportion of ingested microplastics translocate throughout marine mammal bodies posing an exposure risk to both marine mammals and people. For people, exposure could be directly through consumption for those who rely on marine mammals as food and indirectly to peoples globally who consume the same prey resources as marine mammals. Some individuals examined represent samples obtained over two decades ago, suggesting that this process, and thus exposure risk, has occurred for some time. [Display omitted] • Internalized microplastics translocate to marine mammal organs, notably blubber. • Samples containing microplastics spanned over two decades. • 68% of samples contained at least one microplastic particle. • The most common polymer & shape observed were polyethylene & fibers, respectively. • Use of complimentary methods allowed for both mass and count concentrations. [ABSTRACT FROM AUTHOR]

Whale tracking tags often penetrate semi-rigid blubber, with intramuscular sharp tips and toggling barbs under the subdermal sheath to reduce premature shedding. Tag sites can show persistent regional swellings or depressions. Fibroelastic blubber grips a tag, so if muscle shears relative to blubber during locomotion, the tag tip could cavitate the muscle within overall shearing distance. We modeled shearing of blubber relative to muscle, within the dorsalventral peduncular movement range of four common dolphin (Delphinus delphis) cadavers (mean length 186 cm). The net change in angle and hence tip distance moved was calculated with dorsal and ventral flexion, and compared between 1.5 mm diameter needles inserted into blubber only and through blubber into muscle. The greatest shearing value was 3.6 cm, and shearing was most pronounced in the areas ventral and caudal to the dorsal fin. Scaled dummy tags were also inserted and the animal cyclically flexed dorsally and ventrally for 18 h. Tag sites were dissected and cavities around the tag tips documented. If this shearing is comparable in large whales, depressions and regional swellings observed with intramuscular tracking tags are likely the result of tissue loss and repair, respectively. Placing tags para-sagittally anterior to the dorsal fin would cause the least trauma, but pain from such tags remains a concern. [ABSTRACT FROM AUTHOR]

Chronic stress can have detrimental effects on an individual’s health and reproductive success. The use of cortisol quantification as an indicator of stress in free-ranging cetaceans and phocids is increasing but no studies have applied this technique on blubber in otariids. We measured cortisol concentrations in blubber samples obtained from California sea lions, Zalophus californianus , stranded in San Diego County and those incidentally killed in the California drift gillnet fishery. We also measured progesterone concentrations to assess female reproductive status and, in males, as a potential secondary measure of adrenal steroid production. Blubber cortisol and progesterone values were compared across demographic groups (sex and maturity), season, and proportion blubber lipid extracted. Stranded animals (247.3 ± 70.767 SE ng/g blubber) had significantly higher cortisol concentrations compared to fishery bycaught (8.1 ± 2.108 SE ng/g blubber) animals. These findings are likely driven by inherent differences in the cause of death and associated nutritional state coupled with the mean duration of expiration for these two groups of animals (i.e., the duration from an animal’s initial perception of the threat-to-self until death). The duration of transition from healthy state to death in stranded animals is on the order of many hours to weeks while in fishery bycaught animals, this transition occurs much more rapidly (i.e., seconds to tens of minutes). The presumed longer duration of the mortality event in stranded animals gives sufficient time for elevated cortisol to diffuse into the blubber. No significant differences between demographic groups, or season were found. However, blubber cortisol declined inversely with proportion blubber lipid extracted, suggesting utility in assessing long-term nutritional status. Blubber progesterone was significantly higher in mature females than immature females (153.8 ± 54.546 SE ng/g blubber and 9.7 ± 3.60 SE ng/g blubber respectively), containing on average 15 times more progesterone, irrespective of pregnancy state. Additionally, a significant relationship between mean cortisol and progesterone was found in males with >35% blubber lipid (p < 0.0001). This study is an initial step in validating blubber cortisol and progesterone concentrations as a potential marker of stress response and reproductive state, respectively, in otariids. Especially when paired with dart biopsying, this approach could represent a relatively rapid way to assess baseline stress, nutritional status and reproductive states in otariids while minimizing the effects of sampling. [ABSTRACT FROM AUTHOR]

Monitoring of marine mammal steroid hormone status using matrices alternative to blood is desirable due to the ability to remotely collect samples, which minimizes stress to the animal. However, measurement techniques in alternative matrices such as blubber described to date are limited in the number and types of hormones measured. Therefore, a new method using bead homogenization to QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction, C18 post extraction cleanup and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to the measurement of hormone suites in bottlenose dolphin blubber. Validations were conducted in blubber from fresh dead stranded bottlenose dolphin. The final method consisting of two LC separations and garnet bead homogenization was tested for extraction efficiencies. Steroids were separated using a biphenyl column for reproductive hormones and C18 column for corticosteroids. Three hormones previously noted in blubber, testosterone, progesterone, and cortisol, were quantified in addition to previously unmeasured androstenedione, 17-hydroxyprogesterone, 11-deoxycortisol, 11-deoxycorticosterone, and cortisone in a single sample (0.4 g blubber). Extraction efficiencies of all hormones from blubber ranged from 84% to 112% and all RSDs were comparable to those reported using immunoassay methods (< 15%). The method was successfully applied to remote biopsied blubber samples to measure baseline hormone concentrations. Through this method, increased coverage of steroid hormone pathways from a single remotely collected sample potentially enhances the ability to interpret biological phenomena such as reproduction and stress in wild dolphin populations. [ABSTRACT FROM AUTHOR]

The ability to accurately evaluate the energetic health of wildlife is of critical importance, particularly under conditions of environmental change. Despite the relevance of this issue, currently there are no reliable, standardized, nonlethal measures to assess the energetic reserves of large, free-roaming marine mammals such as baleen whales. This study investigated the potential of adipocyte area analysis and further, a standardized adipocyte index ( AI), to yield reliable information regarding humpback whale ( Megaptera novaeangliae) adiposity. Adipocyte area and AI, as ascertained by image analysis, showed a direct correlation with each other but only a weak correlation with the commonly used, but error prone, blubber lipid-percent measure. The relative power of the three respective measures was further evaluated by comparing humpback whale cohorts at different stages of migration and fasting. Adipocyte area, AI, and blubber lipid-percent were assessed by binary logistic regression revealing that adipocyte area had the greatest probability to predict the migration cohort with a high level of redundancy attributed to the AI given their strong linear relationship (r = −.784). When only AI and lipid-percent were assessed, the performance of both predictor variables was significant but the power of AI far exceeded lipid-percent. The sensitivity of adipocyte metrics and the rapid, nonlethal, and inexpensive nature of the methodology and AI calculation validate the inclusion of the AI in long-term monitoring of humpback whale population health, and further raises its potential for broader wildlife applications. [ABSTRACT FROM AUTHOR]

In vitro investigations of the health impact of individual chemical compounds have traditionally been used in risk assessments. However, humans and wildlife are exposed to a plethora of potentially harmful chemicals, including organohalogen contaminants (OHCs). An alternative exposure approach to individual or simple mixtures of synthetic OHCs is to isolate the complex mixture present in free-ranging wildlife, often non-destructively sampled from lipid rich adipose. High concentration stock volumes required for in vitro investigations do, however, pose a great analytical challenge to extract sufficient amounts of complex OHC cocktails. Here we describe a novel method to easily, rapidly and efficiently extract an environmentally accumulated and therefore relevant contaminant cocktail from large (10–50 g) marine mammal blubber samples. We demonstrate that lipid freeze-filtration with acetonitrile removes up to 97% of blubber lipids, with minimal effect on the efficiency of OHC recovery. Sample extracts after freeze-filtration were further processed to remove residual trace lipids via high-pressure gel permeation chromatography and solid phase extraction. Average recoveries of OHCs from triplicate analysis of killer whale ( Orcinus orca ), polar bear ( Ursus maritimus ) and pilot whale ( Globicephala spp.) blubber standard reference material (NIST SRM-1945) ranged from 68 to 80%, 54–92% and 58–145%, respectively, for 13 C-enriched internal standards of six polychlorinated biphenyl congeners, 16 organochlorine pesticides and four brominated flame retardants. This approach to rapidly generate OHC mixtures shows great potential for experimental exposures using complex contaminant mixtures, research or monitoring driven contaminant quantification in biological samples, as well as the untargeted identification of emerging contaminants. [ABSTRACT FROM AUTHOR]

The study of blubber fatty acids (FAs) has attracted increasing scientific interest due mainly to its potential use as trophic markers. This is possible because most FAs are transferred unmodified from the prey to the blubber of the predator. Additionally, FAs have also been used to understand other aspects of the biology of marine mammals, including thermoregulation and reproductive stage. The aim of this study is to determine the FA composition of the blubber of the crabeater seal, which has not been reported before, and identify stratification of FAs across the blubber layer. Seals were captured in the western Antarctic Peninsula during the austral summer of 2015 and a whole blubber core (down to the muscle layer) sample was collected. The blubber core was sub-sectioned into inner and outer layers and analysed for FAs. The FA composition of crabeater seals was similar to other marine mammals, with high proportions of 18:1ω9, 16:1ω7, and 16:0. These FAs are endogenous, that is, they can be readily synthesised by mammals. However, the high proportions of 22:6ω3 and 20:5ω3 are unusual among other marine mammals. These FAs are potentially reflecting the diet of crabeater seals, as they have a dietary origin and are known to be abundant in krill, the main prey item of this predator. Inner and outer layers were significantly different indicating a stratification of blubber FAs. The pattern of stratification is ubiquitous in marine mammals, with monounsaturated FAs increasing towards the outer layer, and saturated and polyunsaturated FAs increasing towards the inner layer. This difference between inner and outer layers may indicate that they have different metabolic roles. Because most dietary FAs were more abundant in the inner layer, this is likely to be the section where the dietary process takes place. The higher proportions of monounsaturated FAs in the outer layer suggest that this section of the blubber plays a more functional role, probably related to thermoregulation, as these FAs prevent rigidity and improve fluidity, which is particularly important in cold environments. [ABSTRACT FROM AUTHOR]

Leatherback turtles (Dermochelys coriacea) are capital breeders that accumulate blubber (33 kJ g-1 wet mass) by hyperphagia on a gelatinous diet at high latitudes; they breed in the tropics. A jellyfish diet is energy poor (0.1-0.2 kJ g-1 wet mass) so leatherbacks must ingest large quantities. Two published estimates of feeding rate [50% body mass day-1 (on Rhizostoma pulmo) and 73% body mass day-1 (on Cyanea capillata)] have been criticised as too high. Jellyfish have high salt and water contents that must be removed to access organic material and energy. Most salt is removed (as NaCl) by paired lachrymal salt glands. Divalent ions are lost via the gut. In this study, the size of adult salt glands (0.622 kg for a 450 kg turtle; relatively three times the size of salt glands in cheloniid turtles) was measured for the first time by computed tomography scanning. Various published values for leatherback field metabolic rate, body fluid composition and likely blubber accumulation rates are combined with known jellyfish salt, water and organic compositions to calculate feasible salt gland secretion rates and feeding rates. The results indicate that leatherbacks can produce about 10-15 ml secretion g-1 salt gland mass h-1 (tear osmolality 1800 mOsm kg-1). This will permit consumption of 80% body mass day-1 of C. capillata. Calculations suggest that leatherbacks will find it difficult/impossible to accumulate sufficient blubber for reproduction in a single feeding season. Rapid jellyfish digestion and short gut transit times are essential. [ABSTRACT FROM AUTHOR]

B-cell lymphoma, a common morphologic variant of non-Hodgkin lymphoma, has been associated with persistent pollutants in humans, but this association is not well-characterized in top-level predators sharing marine resources with humans. We characterized and compared blubber contaminants and hormones of a pregnant harbor porpoise ( Phocoena phocoena) with B-cell lymphoma, with those in two presumed healthy fishery by-caught porpoises with no lymphoma: a pregnant adult and female juvenile. Common historic use compounds, including polychlorinated biphenyls, polybrominated diphenyl ethers, and pesticides, were evaluated in blubber samples from three porpoises. In addition, blubber cortisol and progesterone levels (ng/g) were determined in all three animals. Total pollutant concentrations were highest in the juvenile porpoise, followed by the lymphoma porpoise and the nonlymphoma adult. Blubber cortisol concentrations were 191% greater in the pregnant with lymphoma porpoise compared with the pregnant no lymphoma porpoise, and 89% greater in the juvenile female compared with the pregnant no lymphoma porpoise. Although both adults were pregnant, progesterone levels were substantially greater (90%) in the healthy compared with the lymphoma adult. Health monitoring of top-level marine predators, such as porpoise, provides a sentinel measure of contaminants that serve as indicators of potential environmental exposure to humans. [ABSTRACT FROM AUTHOR]

The ringed seal, Pusa hispida , is a keystone species in the Arctic marine ecosystem, and is proving a useful marine mammal for linking polychlorinated biphenyl (PCB) exposure to toxic injury. We report here the first de novo assembled transcriptome for the ringed seal (342,863 transcripts, of which 53% were annotated), which we then applied to a population of ringed seals exposed to a local PCB source in Arctic Labrador, Canada. We found an indication of energy metabolism imbalance in local ringed seals ( n = 4), and identified five significant gene transcript targets: plasminogen receptor ( Plg-R(KT) ), solute carrier family 25 member 43 receptor ( Slc25a43 ), ankyrin repeat domain-containing protein 26-like receptor ( Ankrd26 ), HIS30 (not yet annotated) and HIS16 (not yet annotated) that may represent indicators of PCB exposure and effects in marine mammals. The abundance profiles of these five gene targets were validated in blubber samples collected from 43 ringed seals using a qPCR assay. The mRNA transcript levels for all five gene targets, ( Plg-R(KT) , r 2 = 0.43), ( Slc25a43 , r 2 = 0.51), ( Ankrd26 , r 2 = 0.43), (HIS30, r 2 = 0.39) and (HIS16, r 2 = 0.31) correlated with increasing levels of blubber PCBs. Results from the present study contribute to our understanding of PCB associated effects in marine mammals, and provide new tools for future molecular and toxicology work in pinnipeds. [ABSTRACT FROM AUTHOR]

The article presents the study of thermal properties of beaked whale blubber and properties affected by ontogenetic changes in wax content. Topics discussed include analysis of variance used to compare the lipid content, wax ester content and conductivity values; wax content increases rapidly across ontogeny; and blubber of Gervais' beaked whales consisting lipid and wax content acting as insulated material.

The article presents the study to quantify the changes occurred in pinniped fur as an insulator while submerged in water. Topics discussed include thermal conductivity and thermal resistance helps to detect the function of fur while submerged in water; ability of pinnipeds to maintain a layer of air beneath the fur; and species developed specialized insulation in the form of modified fur or blubber made up of subcutaneous tissue helping mammals to keep them warm.

There are few cetacean tissue-specific polycyclic aromatic hydrocarbon (PAH) concentration studies in the Mediterranean, despite this region is among the most subjected to chemical contamination. PAH analyses were conducted in different tissues of striped dolphins (Stenella coeruleoalba , N = 64) and bottlenose dolphins (Tursiops truncatus , N = 9) stranded along the French Mediterranean coastline from 2010 to 2016. Comparable levels were measured in S. coeruleoalba and T. trucantus (1020 and 981 ng g−1 lipid weight in blubber, 228 and 238 ng g−1 dry weight in muscle, respectively). The results suggested a slight effect of maternal transfer. The greatest levels were recorded by urban and industrial centers, and decreasing temporal trends were observed in males muscle and kidney, but not in other tissues. As a conclusion, the elevated levels measured could represent a serious threat to dolphins populations in this region, particularly by urban and industrial centers. [Display omitted] • PAH were elevated in Stenella coeruleoalba and Tursiops truncatus. • Lower levels in S. coeruleoalba females suggest little maternal transfer. • Naphthalene, fluorene, 5- and 6-rings PAHs dominated in all tissues. • Highest levels were localized by urban and industrial areas. • Constant time trends in blubber and liver, possibly decreasing in muscle and kidney. [ABSTRACT FROM AUTHOR]

Lipophilic persistent organic pollutants (POPs) tend to biomagnify in food chains, resulting in higher concentrations in species such as killer whales ( Orcinus orca ) feeding on marine mammals compared to those consuming fish. Advancements in dietary studies include the use of quantitative fatty acid signature analysis (QFASA) and differentiation of feeding habits within and between populations of North Atlantic (NA) killer whales. This comprehensive study assessed the concentrations of legacy and emerging POPs in 162 killer whales from across the NA. We report significantly higher mean levels of polychlorinated biphenyls (PCBs), organochlorine pesticides, and flame retardants in Western NA killer whales compared to those of Eastern NA conspecifics. Mean ∑PCBs ranged from ∼100 mg/kg lipid weight (lw) in the Western NA (Canadian Arctic, Eastern Canada) to ∼50 mg/kg lw in the mid-NA (Greenland, Iceland) to ∼10 mg/kg lw in the Eastern NA (Norway, Faroe Islands). The observed variations in contaminant levels were strongly correlated with diet composition across locations (inferred from QFASA), emphasizing that diet and not environmental variation in contaminant concentrations among locations is crucial in assessing contaminant-associated health risks in killer whales. These findings highlight the urgency for implementing enhanced measures to safely dispose of POP-contaminated waste, prevent further environmental contamination, and mitigate the release of newer and potentially harmful contaminants.