Blubber fat deposition in mysticeti whales

Ackman, R. G.; Hingley, J.; Eaton, C. A.; Šipoš, Ján; Mitchell, Edward D.

doi:10.1139/z75-158

Cited by 64 publications

(43 citation statements)

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“…This thin connective tissue layer was not found in the histological sections used in this study. Similarly, histological inspection did not reveal the presence of any discernible collagenous layer interrupting the hypodermis, as has been described in Nova Scotian sei whales (Ackman et al, 1975). In this study, southern right whales possessed uninterrupted collagen bundles surrounded by large amounts of adipose tissue that occurred below the dermis.…”

Section: Microscopic Characteristics Of Southern Right Whale Skinsupporting

confidence: 75%

“…It may, therefore, be possible that this innermost layer only becomes evident during the fattening/feeding stages of the animal's nutritional cycle, being comparable to the ''isterlag'' or ''leaf fat'' described by Heyerdahl (1932), Tveraaen (1935), and Pedersen (1950) in very fat Antarctic baleen whales. Ackman et al (1975) have likened the layer of collagenous and elastic fibers, which interrupts the hypodermal layer of the integument of Nova Scotian sei whales (also caught during the summer feeding season), to this layer.…”

Section: Microscopic Characteristics Of Southern Right Whale Skinmentioning

confidence: 99%

“…The lateral samples include measurements taken from a juvenile and the marked decrease in blubber thickness in a craniocaudal direction, especially in Position 5, helps create the laterally compressed, stream-lined tailstock. Unfortunately, the lateral location of these samples makes them incomparable to results from other investigations (Ackman et al, 1975;Lockyer et al, 1985), but the laterally compressed nature of the cetacean peduncle (and the underlying structure of the blubber) has been proposed as a mechanism for creating elastic energy that assists in propulsion (Summers, 2001;Hamilton et al, 2004). The deep-core sampling technique was a successful first attempt at obtaining representative integument samples from a free-swimming balaenid.…”

Section: Microscopic Characteristics Of Southern Right Whale Skinmentioning

confidence: 99%

“…Superficially, it is continuous with the reticular layer of the dermis, while proximally it is separated from the panniculus carnosus by loose connective tissue (superficial fascia). The distinction between the dermis and hypodermis is not always clear, as adipocytes extend to some extent up to the dermis and heavy collagen bundles ramify throughout the blubber (Parry, 1949;Simpson and Gardner, 1972;Ackman et al, 1975;Sokolov, 1982). The hypodermis is architecturally simple: it is usually composed of adipose tissue supported by vasculature, nerves, and varying amounts of collagen fibers.…”

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confidence: 99%

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Structure of the integument of southern right whales, Eubalaena australis

Reeb

Best

Kidson

2007

The Anatomical Record

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Skin (integument) anatomy reflects adaptations to particular environments. It is hypothesized that cetacean (whale) integument will show unique anatomical adaptations to an aquatic environment, particularly regarding differences in temperature, density, and pressure. In this study, the gross and histological structure of the southern right whale integument is described and compared with terrestrial mammals and previous descriptions of mysticete (baleen whale) and odontocete (toothed whale) species. Samples were taken of the integument of 98 free-swimming southern right whales, Eubalaena australis, and examined by both light and electron microscopy. Results show that three epidermal layers are present, with the stratum corneum being parakeratotic in nature. As in bowhead whales, southern right whales possess an acanthotic epidermis and a notably thick hypodermis, with epidermal rods and extensive papillomatosis. However, unlike bowhead whales, southern right whales possess an uninterrupted hypodermal layer. Surprisingly, the integument of balaenids (right and bowhead mysticetes) in general is more like that of odontocetes than that of the more closely related balaenopterids (rorqual mysticetes). Similarities to odontocetes were found specifically in the collagen fibers in a fat-free zone of the reticular dermal layer and the elastic fibers in the dermal and hypodermal layers. Callosities, a distinctive feature of this genus, have a slightly thicker stratum corneum and are usually associated with hairs that have innervated and vascularized follicles. These hairs may function as vibrissae, thus aiding in aquatic foraging by allowing rapid detection of changes in prey density. Although the thick insulatory integument makes right whales bulky and slow-moving, it is an adaptation for living in cold water. Epidermal thickness, presence of epidermal rods, and callosities may act as barriers against mechanical injury from bodily contact with conspecifics or hard surfaces in the environment (e.g., rocks, ice). Anat Rec, 290:596-613, 2007. 2007 Wiley-Liss, Inc.

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Section: Microscopic Characteristics Of Southern Right Whale Skinsupporting

confidence: 75%

Section: Microscopic Characteristics Of Southern Right Whale Skinmentioning

confidence: 99%

Section: Microscopic Characteristics Of Southern Right Whale Skinmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Structure of the integument of southern right whales, Eubalaena australis

Reeb

Best

Kidson

2007

The Anatomical Record

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“…Histological and biochemical evidence from stranded specimens suggest that blubber is stratified in cetaceans (Ackman et al, 1965(Ackman et al, , 1975aLockyer et al, 1984;Koopman et al, 1996;Koopman et al, 2002;Struntz et al, 2004). For example, in fin whales (Balaenoptera physalus), described the vertical stratification of lipid content.…”

Section: Hippocampusmentioning

confidence: 99%

Approaches for assessing the presence and impact of thyroid hormone disrupting chemicals in delphinid cetaceans

Montie¹

2006

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Cetacean blubber is a primary site for lipid storage, which the animal utilizes during periods of energetic stress. It is important to understand how the blubber responds to factors such as ontogeny, water temperature, reproductive status, and nutritional state because blubber is also the primary bioaccumulation site for persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs). During periods of lipid mobilization such as lactation, PCBs from the blubber are mobilized into the circulatory system and may cause toxic effects. One particular toxic mechanism may include the induction of cytochrome P450 enzymes in the integument and liver, which could enhance the biotransformation of PCBs to hydroxylated metabolites (OH-PCBs). OH-PCBs may then interfere with thyroid hormone dependent neurodevelopment. The goals of these studies were to investigate the relationships between lipid dynamics and PCB effects and to devise a quantitative approach to assess neurodevelopment in delphinid cetaceans. Blubber morphology, cytochrome P450 1A1 (CYP1A1) expression in the skin-blubber biopsy, blubber and plasma PCBs, and plasma OH-PCBs were assessed in bottlenose dolphins (Tursiops truncatus). In addition, magnetic resonance (MR) images of the postmortem brain in situ were obtained from Atlantic white-sided dolphin (Lagenorhynchus acutus) specimens.These results showed that: 1) Factors such as ontogeny, water temperature, and reproductive status affected blubber morphology in bottlenose dolphins. In response to warmer water, the lipid content of the blubber decreased and this appeared to involve loss of lipids from adipocytes in the middle blubber layer. Similar to the effects of starvation on blubber morphology, lactation decreased adipocyte size predominantly in the deeper blubber, 2) CYP1A1 levels in the deep blubber were significantly related to the total plasma TEQ 98 concentrations, adipocyte shrinkage, and plasma OH-PCB levels, 3) Through in situ MR imaging of stranded, Atlantic white-sided dolphin specimens, the size of brain structures that depend on thyroid hormones for maturation could be measured accurately. Future studies can use this technique, coupled with chemical analysis of brain regions, to determine if thyroid hormone disrupting chemicals in delphinid cetaceans are associated with changes in the size of brain structures.

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Morphology of the Eye of the Southern Right Whales (Eubalaena australis)

Buono

Fernández

Herrera

2011

The Anatomical Record

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Recently, there has been a growing interest in the anatomy and optics of the visual system of cetaceans. However, much of the new information has been focused on odontocetes, and relatively little is known about the visual anatomy of baleen whales. The aim of this study was describe the eye anatomy of the southern right whale (Eubalaena australis). Eye samples were collected from 26 calves, four adults with known body length, as well as two specimens of unknown body length that had stranded near their nursery ground at Península Vald es, Argentina, over 6 years. We provide anatomical descriptions of the eyeball and extraocular structures, as well as quantitative data in the form of eyeball, corneal, scleral, and lens measurements. To explore the sensitivity of the eye to light, the f-number was estimated in one specimen. We found that the eyes of the calves differed from those of the adults in having less periorbital fat surrounding the eyeball. We also observed variations in the abundance of periorbital fat among the adult specimens. The regression analysis revealed a correlation between body length and eyeball size. By contrast, the dimensions of the cornea were only weakly correlated with body length. The estimated f-number suggests that the optical sensitivity of the Eubalaena australis eye is relatively low. However, caution had to be taken in interpreting f-number as a proxy of eye sensitivity because it depends on the lens size, which can be affected by the fixation methods used. Anat Rec,

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Blubber fat deposition in mysticeti whales

Cited by 64 publications

References 0 publications

Structure of the integument of southern right whales, Eubalaena australis

Structure of the integument of southern right whales, Eubalaena australis

Approaches for assessing the presence and impact of thyroid hormone disrupting chemicals in delphinid cetaceans

Morphology of the Eye of the Southern Right Whales (Eubalaena australis)

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