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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Age determination, reproduction, growth and population analysis of the harbor seal, Phoca vitulina richardi gray

Bigg, Michael Andrew January 1966 (has links)
Studies have been made on age determination, reproduction, growth and population structure in the harbour seal (Phoca vitulina richardi). They are based upon gross and histological examinations of reproductive tracts, growth measurements, and associated canine teeth of 42 prenatal and 319 postnatal specimens collected between 1964 and 1965. In postnatal seals cementum annulations were used as the criterion of age. Two annulations are deposited annually, a translucent "dense, inorganic" band during the winter and spring and an opaque "less dense, more organic" band during the summer and fall. Their formation may result from an internal rhythm. In southeastern Vancouver Island (southern British Columbia) parturition occurs primarily during July, lactation then lasts 6 weeks with ovulation shortly thereafter in September. Implantation is delayed for 2 to 2½ months and birth is about 230 days later. The male's main breeding season begins at least 4 months in advance of the female's but ends shortly after. Extensive clines in the timing of the reproductive cycle of both sexes are found in the Pacific and Atlantic Oceans. First ovulations occur at 2 to 5 years of age with peak periods at 2 and 3 years. About 88.9% of all adult females produce young each year. Males mature at 5 and 6 years of age. Prenatal males and females grow at similar rates. Postnatal males, however, grow slightly faster and larger being about 10% longer and 36% heavier at asymptotic sizes. Sex ratios are about 1 : 1 from implantation until males reach sexual maturity at 5 years, their mortality rate then increases resulting in a gradually increasing percentage of females in older age groups. Males generally do not live longer than 20 years and females seldom more than 30 years. In a random kill sample the average annual sex ratio is 46.9% males, and 49.6% of all females and 33.7% of males are mature. From bounty return records and reproductive and population data a minimum population estimate of 75,000 seals is made for British Columbia. This is a density of about 4.4 seals per mile of coastline. / Science, Faculty of / Zoology, Department of / Graduate

Food consumption by larval gizzard shad: zooplankton effects and its implications for reservoir communities

Dettmers, John Michael January 1991 (has links)
No description available.

The impact of zebra mussels (Dreissena polymorpha) on pelagic food webs

Pontius, Ruth Atkins January 2000 (has links)
No description available.

Body weights and selected organ measurements from pigs stillborn or dying neonatally

Herren, Charles Edward January 2011 (has links)
Typescript. / Digitized by Kansas Correctional Industries

The functional significance of grooming behaviour in higher primates the case of free-living chimpanzees /

Slater, Kerry. January 2009 (has links)
Thesis (Ph.D.(Zoology)) -- University of Pretoria, 2009. / Includes bibliographical references.

Animals in the landscape : an analysis of the role of the animal image in representations of identity in selected Australian feature films from 1971 to 2001 /

Forscher, Helene. January 2007 (has links)
Thesis (PhD) -- Bond University, 2007. / "A dissertation submitted in fulfillment of the requirements of the degree of Doctor of Philosophy"-- t.p. Bibliography: leaves 266-281. Also available via the World Wide Web.

Der Einfluss des Verschuldens des Beschädigten im Falle des Schadens durch Tiere und Gehilfen /

Auerbach, Herbert Manfred. January 1913 (has links)
Thesis (doctoral)--Friedrich-Wilhelm-Universität zu Breslau.

Die Grenzen der Tierhalterhaftung /

Hesse, Hans. January 1934 (has links)
Thesis (doctoral)--Universität Marburg.

Studies in the ecology of the benthic diptera of Lake Mendota

Dugdale, Richard C. January 1955 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 98-99).

Die rechtliche Bedeutung des Satzes 2 des [Paragraph] 833 BGB.

Habes, Theo, January 1913 (has links)
Rostock, Jur. Diss. v. 6. Febr. 1914, Ref. Matthiass.

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