Author: Andrew J. Read
Publisher:
ISBN: 9789072743077
Category : Harbor porpoise
Languages : en
Pages : 410

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Author:
Publisher:
ISBN:
Category : Harbor porpoise
Languages : en
Pages : 324

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Author: Annemarie Surlykke
Publisher: Springer
ISBN: 1461491460
Category : Science
Languages : en
Pages : 312

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Book Description
Two groups of animals, bats and odontocetes (toothed whales), have independently developed the ability to orient and detect prey by biosonar (echolocation). This active mechanism of orientation allows these animals to operate under low light conditions. Biosonar is a conceptual overview of what is known about biosonar in bats and odontocetes. Chapters are written by bat and odontocetes experts, resulting in collaborations that not only examine data on both animals, but also compare and contrast mechanisms. This book provides a unique insight that will help improve our understanding of biosonar in both animal groups.

Author: International Union for Conservation of Nature and Natural Resources
Publisher: IUCN
ISBN: 9782880329365
Category : Nature
Languages : en
Pages : 450

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Author: Bruno Cozzi
Publisher: Academic Press
ISBN: 0124076556
Category : Science
Languages : en
Pages : 458

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Book Description
The Anatomy of Dolphins: Insights into Body Structure and Function is a precise, detailed, fully illustrated, descriptive, and functionally oriented text on the anatomy and morphology of dolphins. It focuses on a number of delphinid species, with keynotes on important dolphin-like genera, such as the harbor porpoise. It also serves as a useful complement for expanding trends and emphases in molecular biology and genetics. The authors share their life-long expertise on marine mammals in various disciplines. Written as a team rather than being prepared as a collection of separate contributions, the result is a uniform and comprehensive style, giving each of the different topics appropriate space. Many color figures, which use the authors’ access to wide collections of unique dolphin and whale material, round out this exceptional offering to the field. Includes high-quality illustrations, drawings, halftone artwork, photographic documentations, microphotos, and tables detailing dolphin anatomy, function, and morphology Facilitates education and training of students of all basic research and applied sciences dedicated to marine biology and the medical care of marine mammals Brings together the current knowledge and information on this topic, including those in obscure past or non-English publications, or scattered in short chapters in volumes Covers a number of delphinid species and serves as a useful complement for expanding trends in molecular biology and genetics

Author: Tina Kesselring
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
As top predators and the only native cetacean species, harbour porpoises (Phocoena phocoena) play an important role in the German oceanic ecosystems. Due to the fact, that harbour porpoises are already exposed to numerous anthropogenic influences, the reproductive lifespan is a sensitive time frame and reproductive health might be the key to a stabile population size in the German ocean areas. This study focussed on the macroscopic and microscopic analysis of the reproductive organs of both, female and male individuals from the North and Baltic Seas. With these analyses it was possible to obtain data on life history events like postnatal gonadal development, age at sexual maturity and seasonality. For female harbour porpoises, we investigated the first signs of sexual maturity for a period of almost two decades (1990 - 2016). Ovaries from 111 female harbour porpoises from the German North and Baltic Sea were examined for the presence and morphological structure of follicles, corpora lutea and corpora albicantia. These specimens were selected by the criteria of status of decomposition in order to exclude biases due to poor tissue preservation. Based on the ovarian characteristics we performed the first model-based estimation of age at sexual maturity for harbour porpoises from German waters. Additionally, we produced a demographical age structure based on all female strandings and bycatches from German coasts. For males, the testes of 127 harbour porpoises from the North and Baltic Sea that became stranded or by-caught in the years 1998 to 2016 were histologically examined. For the identification of changes in testes morphology and morphometry of adult harbour porpoises during the course of the year, special characteristics like germ cell associations (stages) and diameter of seminiferous tubules were noted for each month. Our results of the examination of female harbour porpoises showed that corpora lutea and corpora albicantia as signs of former ovulation events could be found in individuals at an age of 4.95 (± 0.6) years. No significant differences between specimens from the North and Baltic Sea were detected. However, the average age at death differed significantly with 5.70 (± 0.27) years for North Sea animals and 3.67 (± 0.30) years for those in the Baltic Sea. The histological analysis of the testes showed that first signs of sexual maturity could be detected in animals older than three years, while individuals older than four years could be listed as 'adults', showing a staging of spermatogenesis and a seasonal circle. Since more than one stage of spermatogenesis could be found per cross section of the seminiferous tubules of adult harbour porpoises, these results are similar to findings in men and some ape species. This rare phenomenon is called multi-stage-arrangement. In sexually active males from the high breeding season (June and July) eight stages of spermatogenesis were identified and all stages occurred simultaneously, while during the non-breeding season (August to May) only residual spermatogenesis or constituent germ cell populations were found. In addition, an increasing number of missing germ cell generations from August to September was encountered. Our studies provide a detailed description and analysis of the functional anatomy and histology of the female and male reproductive organs of harbour porpoises and might serve as baseline studies for further investigations that deal with effects of anthropogenic influences on the reproductive system of this top predator in the German North and Baltic Sea, the harbour porpoise.

Author: Joseph R. Geraci
Publisher: National Aquarium in Baltimore
ISBN: 0977460908
Category : Marine mammals
Languages : en
Pages : 386

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Book Description
Comprehensive manual for understanding and carrying out marine mammal rescue activities for stranded seals, manatees, dolphins, whales, or sea otters.

Author: Whitlow W.L. Au
Publisher: Springer Science & Business Media
ISBN: 1461243564
Category : Medical
Languages : en
Pages : 288

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Book Description
The extraordinary ability of dolphins to echolocate has fascinated scientists and the public since its discovery in the late 1950's. This is the first book to summarize modern research in this area, and presents a broad synthesis of this very interdisciplinary subject. The author is an internationally-recognized expert on dolphin sonar and is thus in a unique position to bring together research on the physiological, mathematical and engineering aspects of the subject. Of interest to auditory researchers, electrical engineers, acoustical physicists, and mammalian physiologists.

Author: Randall R. Reeves
Publisher: IUCN
ISBN: 2831706564
Category : Cetacea
Languages : en
Pages : 238

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Book Description

Author: Gregory P Donovan
Publisher:
ISBN:
Category : Porpoises
Languages : en
Pages : 572

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Book Description