DETERMINATION OF PREGNANCY STATUS FROM BLUBBER SAMPLES IN MINKE WHALES (BALAENOPTERA ACUTOROSTRATA)

We have developed a new technique for the quantitative extraction of progesterone from very small pieces of muscle tissue of minke whales (Balaenoptera acutorostrata) post mortem. Ethanol extracts of approximately 0.5 g of tissue contained, on average, 15.3 ng/g progesterone in the case of pregnant females (SD = 12.7, n = 9) and 0.32 ng/g progesterone in the case of immature females (SD = 0.03, n = 9). Differences in muscle progesterone levels between females in the two reproductive states were significant, as has been previously reported also for serum levels. Our technique is expected to be applicable in the near future to the determination of the presence or absence of the corpus luteum in the ovaries and the reproductive status of free-ranging female whales, provided that sampling techniques for muscle biopsies are developed.

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Corneal anatomy of marine mammals

Canadian Journal of Zoology ◽

10.1139/z93-320 ◽

1993 ◽

Vol 71 (11) ◽

pp. 2282-2290 ◽

Cited By ~ 3

Author(s):

M. T. Pardue ◽

J. G. Sivak ◽

K. M. Kovacs

Keyword(s):

Marine Mammals ◽

Equatorial Region ◽

Balaenoptera Acutorostrata ◽

Marine Habitat ◽

Corneal Surface ◽

Balaenoptera Physalus ◽

Phoca Groenlandica ◽

Minke Whales ◽

Transmission Electron ◽

Ultrathin Sections

The corneal anatomy of fin whales (Balaenoptera physalus), minke whales (Balaenoptera acutorostrata), harp seals (Phoca groenlandica), ringed seals (Phoca hispida), and bearded seals (Eriganthus barbatus) was examined to determine if marine mammals have evolved specialized corneas for life in a marine habitat. One to seven eyes of each species were analyzed: paraffin sections stained with haematoxylin and eosin for light microscopy; and ultrathin sections for transmission electron microscopy. All corneas contain the five typical mammalian layers: epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. The corneas of these marine mammals are thicker than human corneas because of a thicker stromal layer. The other layers are thinner than those found in humans, except for the epithelial layer in the bearded seal and the cetaceans where it may provide extra protection for the eye during feeding behaviour. The epithelial cells in all corneas studied have an abundance of tonofilaments, which may strengthen the cells and distribute force across the corneal surface. No special organization of collagen fibrils was found in the stroma that would offer protection from ultraviolet radiation or glare for pinnipeds when on ice. The thickness of the sclera in the cetaceans may serve to hold the inner globe of the eye in an elliptical shape, while the thinning of the sclera in the equatorial region in pinnipeds may flatten the eye in air to reduce aerial myopia.

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A Multi-elemental Approach to Identification of Subpopulations of North Atlantic Minke Whales Balaenoptera Acutorostrata

Wildlife Biology ◽

10.2981/0909-6396(2007)13[84:amatio]2.0.co;2 ◽

2007 ◽

Vol 13 (1) ◽

pp. 84-97 ◽

Cited By ~ 2

Author(s):

Erik W. Born ◽

Michael C. S. Kingsley ◽

Frank F. Rigét ◽

Rune Dietz ◽

Per Møller ◽

...

Keyword(s):

North Atlantic ◽

Balaenoptera Acutorostrata ◽

Minke Whales

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Do minke whales (Balaenoptera acutorostrata) digest wax esters?

British Journal Of Nutrition ◽

10.1079/bjn19950174 ◽

1995 ◽

Vol 74 (5) ◽

pp. 717-722 ◽

Cited By ~ 10

Author(s):

Erling S. Nordøy

Keyword(s):

Energy Density ◽

Dry Matter ◽

General Pattern ◽

Dry Mass ◽

Wax Esters ◽

Gut Contents ◽

Wax Ester ◽

Balaenoptera Acutorostrata ◽

Minke Whales

Mammals are known to utilize wax esters with an efficiency of less than 50%. The purpose of the present study was to examine whether or not minke whales (Balaenoptera acutorostrata), which at times may eat considerable amounts of wax-ester-rich krill, represent an exception to this general pattern. Samples of fresh undigested forestomach, as well as colon, contents were obtained from minke whales (n5) that had been feeding on krill (Thysanoessa inermis) for some time. The samples were analysed for dry mass, energy density, lipid content and the major lipid classes, including wax esters. The concentrations of wax esters were compared with previous estimates of dry-matter disappearance of the same type of prey using anin vitrotechnique, to calculate the dry-matter digestibility of wax esters (DMDwax). Wax esters contributed 21% of the energy and 47% of total lipids in the krill diet. The energy density of gut contents decreased by 50% after their passage from forestomach to the end of the colon. The DMDwaxwas 94·1 (SD 2·8)% (n5). This high DMDwaxand the occurrence of fatty alcohols, one of the products of wax-ester hydrolysis, in faeces show that minke whales are very efficient digesters of wax esters and absorb most of the energy-rich products of this process.

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Estimated food consumption of minke whales Balaenoptera acutorostrata in Northeast Atlantic waters in 1992-1995

NAMMCO Scientific Publications ◽

10.7557/3.2972 ◽

2000 ◽

Vol 2 ◽

pp. 65 ◽

Cited By ~ 17

Author(s):

Lars P Folkow ◽

Tore Haug ◽

Kjell T Nilssen ◽

Erling S Nordøy

Keyword(s):

Barents Sea ◽

Regional Distribution ◽

Clupea Harengus ◽

Mortality Factor ◽

Point Estimate ◽

Melanogrammus Aeglefinus ◽

Balaenoptera Acutorostrata ◽

Northeast Atlantic ◽

Minke Whales ◽

Prey Items

Data on energy requirements, diet composition, and stock size were combined to estimate the consumption of various prey species by minke whales (Balaenoptera acutorostrata) in Northeast Atlantic waters. In the period 1992-1995, the stock of 85,000 minke whales appeared to have consumed more than 1.8 million tonnes of prey per year in coastal waters off northern Norway, in the Barents Sea and around Spitsbergen during an assumed 6 month stay between mid-April and mid-October.Uncertainties in stock estimates suggest a 95% confidence range of 1.4 - 2.1 million tonnes. The point estimate was composed of 602,000 tonnes of krill Thysanoessa spp., 633,000 tonnes of herring Clupea harengus, 142,000 tonnes of capelin Mallotus villosus, 256,000 tonnes of cod Gadus morhua, 128,000 tonnes of haddock Melanogrammus aeglefinus and 54,500 tonnes of other fish species, including saithe Pollaehius virens and sand eel Ammodytes sp. Consumption of various prey items by minke whales may represent an important mortality factor for some of the species. For example, the estimated annual consumption of herring corresponds to about 70% of the herring fisheries in the Northeast Atlantic in 1995. Minke whale diets are subject to year-to-year variations due to changes in the resource base in different feeding areas. Thus, the regional distribution of consumption of different prey items is highly dynamic.

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