Download or read book The Effect of Temperature on Circulating Levels of Methyl Farnesoate and Ecdysteroid Hormones in Female Snow Crab Chionoecetes Opilio from the Bering Sea written by Jacqueline Loretta Mitchell and published by . This book was released on 2007 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Methyl farnesoate, a reproductive hormone in crustaceans, was detected for the first time in the hemolymph of female Chionoecetes opilio. Ovigerous crabs were maintained at -1,0, 1, and 3° C to represent near bottom temperatures of the Bering Sea, throughout a reproductive cycle to assess changes, and temperature effects, in hormone levels associated with ovarian maturation, hatching and subsequent extrusion of the next clutch. Methyl farnesoate (MF) levels did not change significantly in any treatment throughout the duration of egg incubation. Levels of MF significantly decreased in crabs exposed to -1 and 0° C when initial versus post extrusion levels were compared. Ecdysteroid levels remained low throughout the egg incubation period but increased significantly after extrusion in all treatments except the 0° C treatment. Decrease in temperature significantly prolonged time to extrusion between all temperature groups except 3 and 1 ° C. Extrusion was delayed in the 0 and -1 ° C treatments when compared to the 3 and 1 ° C treatments. The duration of extrusion increased by as much as 77% (between -1 and 0° C) as temperature decreased, suggesting changes in temperature can have a significant effect on the reproductive timing in C. opilio"--Leaf iii.
Download or read book Reproductive Indices of Male Snow Crab Chionoecetes Opilio from the Eastern Bering Sea written by Marilyn Fox Zaleski and published by . This book was released on 2012 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reproductive success of male snow crab (Chionoecetes opilio) is complicated by two different life history stages; male C. opilio undergo a terminal molt prior to adulthood which is marked by an allometric change in chela size. While adolescent males can produce spermatophores, terminally molted males are most successful in mating and reproduction. Molting and mating are hormonally linked, with molting regulated primarily by ecdysteroids and mating regulated by the putative reproductive hormone methyl farnesoate (MF). Methyl farnesoate is structurally related to the insect juvenile III hormone and, in addition to reproduction, may have a role as a juvenilizing hormone in crustaceans. The purpose of this study was to determine how molting affects the reproductive biology of snow crab by comparing the gonadosomatic index(GSI) and concentrations of circulating MF in adolescent and adult males. I used shell condition as a rough estimate of time post molt to compare GSI and MF between new-shell males, those that had molted within one year, and old-shell males, those that had not molted for at least 1 year. I measured GSI as the ratio of gonad weight to whole crab weight and used GSI as a proxy for reproductive fitness; I quantified circulating MF using high performance liquid chromatography. New-shell adolescent and adult males had significantly lower GSI than old-shell males; thus molting compromises the reproductive physiology of male C. opilio. New-shell adolescent males had significantly higher MF levels than old-shell adolescent males, and MF levels remained low after the terminal molt, supporting a juvenilizing role for MF in C. opilio.
Download or read book The Effects of Windchill Exposure on the Snow Crab Chionoecetes Opilio written by Jonathan James Warrenchuk and published by . This book was released on 2001 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Millions of snow crabs, 'Chionoecetes opilio, ' are aerially exposed during sorting in the annual Bering Sea commercial fishery. A laboratory experiment measured snow crab responses to windchill exposure. Crabs were exposed to 8 to 16 m/s windspeed and air temperatures from -2 to -10 C̊ for 5 minutes. Mortality, autonomy, and righting response were assessed for seven days post-treatment. Crabs experienced 40% to 100% mortality at windchill from -10 to 16 C̊. Reduced exposure time significantly reduced mortality. Autonomy was variable but pronounced below -10 C̊ windchill. The righting response was impaired after all but the least severe treatment. Estimates of mortality of discarded snow crab in 1998 were calculated from deadloss of retained crab, a windchill model, and a temperature/windspeed model. No relationship existed between catch deadloss and the windchill conditions when the crabs were caught. Mortality of non-retained snow crab was estimated at 3.6% by the windchill model and 19.6% by the temperature /windspeed model"--Leaf 3.
Download or read book Changes in Embryonic Development Hatching and Zoeae of Snow Crab with Variation in Incubation Temperature written by Joel Benjamin Webb and published by . This book was released on 2005 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The effect of incubation temperature on duration of embryonic development and morphology, weight and energetic content of post-hatch zoeae was described for snow crab, Chionoecetes opilio, from the eastern Bering Sea held at -1, 0, 1, 3, and 6° C in the laboratory from collection to hatch. The mean incubation time increased with decreasing temperature by 32% (113 d) between 6 and -1° C. Extrusion success of females at 6° C was lower versus 0 or 3° C, but the duration of hatching did not vary significantly with incubation temperature. A one-year cycle of embryo incubation was observed, indicating that switching from one to two-year duration of embryo incubation may occur early in development. The energy content and individual weights of post-hatch zoeae were not significantly affected by temperature, indicating that longer incubation periods may not have an energetic cost. The rostro-dorsal length of zoeae incubated at 6° C was smaller than those from cooler temperatures. Conversely, the length of the 3rd abdominal somite increased significantly with decreasing temperature, perhaps serving as an indicator of incubation temperature in field collected zoeae. The consequences of varying incubation temperature appear on post-hatch zoeae appear to be limited between -1° and 6° C."--Leaf iii.
Download or read book Possible Effects of Changes in CIL Temperature and Thickness on Population Dynamics of Snow Crab Chionoecetes Opilio in the Gulf of Saint Lawrence written by Bernard Sainte-Marie and published by . This book was released on 1998 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Treatise on Zoology Anatomy Taxonomy Biology The Crustacea Volume 9 Part C 2 vols written by Peter Castro and published by BRILL. This book was released on 2015-11-24 with total page 1233 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume, 9C, in two parts, covers the Brachyura. With the publication of the ninth volume in the Treatise on Zoology: The Crustacea, we departed from the sequence one would normally expect. Some crustacean groups, mainly comprising the Decapoda, never had a French version produced, and the organization and production of these “new” chapters began independently from the preparation of the other chapters and volumes. Originally envisioned to encompass volume 9 of the series, it quickly became evident that the depth of material for such a volume must involve the printing of separate fascicles. The new chapters have now been completed, and the production of volume 9 was started while volumes 3 through 8 were (and in part still are) in preparation; with this vol. 9C-I & II this volume 9 is now concluded; vols. 1-5 have also been published and vols. 6-8 are being prepared.
Download or read book Lyme Borreliosis in Europe and North America written by Sunil K. Sood and published by John Wiley & Sons. This book was released on 2011-04-18 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: The facts about Lyme disease, from epidemiology to treatment to control Lyme borreliosis, popularly known as Lyme disease, remains the most commonly reported tick-transmitted infection in North America and Europe. A growing body of scientific and clinical evidence has facilitated early diagnosis and effective treatment. Nonetheless, there are a number of misconceptions about this infectious disease that have given rise to unproven, potentially dangerous alternative therapies. In Lyme Borreliosis in Europe and North America, a team of authors whose expertise spans basic research, epidemiology, and clinical practice has compiled evidence-based information on Lyme borreliosis. Presents all the latest evidence needed to diagnose, treat, and prevent Lyme disease Lyme Borreliosis in Europe and North America begins with a review of the disease's epidemiology, the causative Borrelia genospecies, and tick vectors. It then explores pathogenesis, diagnosis, and treatment. Next, the book examines the role of serologic, culture, and molecular diagnostic methods. The book also features a chapter on prognosis, offering an evidence-based review of outcome studies, as well as practical advice to physicians to help them manage the challenging clinical scenario of chronic symptoms attributed to Borrelia infection. The final chapter is a guide to prevention strategies, including the management of tick bites. Examines similarities and differences in Europe and North America Because differences in Borrelia genospecies are responsible for differences in the clinical presentation of Lyme borreliosis between North America and Europe, this book provides descriptions of the disease as it presents on each continent. Most of the chapters have been cowritten by experts on each continent, in order to provide a balanced perspective that combines European and North American findings, practices, and experiences. Helps everyone better understand, treat, and control Lyme disease Lyme Borreliosis in Europe and North America is a comprehensive reference, ideal for clinicians, researchers, and public health officials who seek to treat and control Lyme borreliosis. It will help them better understand the facts and make sense of the misconceptions and myths that surround this infectious disease.
Download or read book Economic and Ecological Significance of Arthropods in Diversified Ecosystems written by Akshay Kumar Chakravarthy and published by Springer. This book was released on 2016-10-20 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arthropods are invertebrates that constitute over 90% of the animal kingdom, and their bio-ecology is closely linked with global functioning and survival. Arthropods play an important role in maintaining the health of ecosystems, provide livelihoods and nutrition to human communities, and are important indicators of environmental change. Yet the population trends of several arthropods species show them to be in decline. Arthropods constitute a dominant group with 1.2 million species influencing earth’s biodiversity. Among arthropods, insects are predominant, with ca. 1 million species and having evolved some 350 million years ago. Arthropods are closely associated with living and non-living entities alike, making the ecosystem services they provide crucially important. In order to be effective, plans for the conservation of arthropods and ecosystems should include a mixture of strategies like protecting key habitats and genomic studies to formulate relevant policies for in situ and ex situ conservation. This two-volume book focuses on capturing the essentials of arthropod inventories, biology, and conservation. Further, it seeks to identify the mechanisms by which arthropod populations can be sustained in terrestrial and aquatic ecosystems, and by means of which certain problematic species be managed without producing harmful environmental side-effects. This edited compilation includes chapters contributed by over 80 biologists on a wide range of topics embracing the diversity, distribution, utility and conservation of arthropods and select groups of insect taxa. More importantly, it describes in detail the mechanisms of sustaining arthropod ecosystems, services and populations. It addresses the contribution of modern biological tools such as molecular and genetic techniques regulating gene expression, as well as conventional, indigenous practices in arthropod conservation. The contributors reiterate the importance of documenting and understanding the biology of arthropods from a holistic perspective before addressing conservation issues at large. This book offers a valuable resource for all zoologists, entomologists, ecologists, conservation biologists, policy makers, teachers and students interested in the conservation of biological resources.
Download or read book Studies on Housing for Alaska Natives written by Dennis R. Wik and published by . This book was released on 1965 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigations of the White Mountain Mercury Deposit Kuskokwim River Basin Alaska written by Raymond P. Maloney and published by . This book was released on 1967 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Outer Continental Shelf Environmental Assessment Program Final Reports of Principal Investigators written by and published by . This book was released on 1984 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Eskimos of the Nushagak River written by James W. VanStone and published by Seattle : University of Washington Press. This book was released on 1967-01-01 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Study of history of cultural change among Eskimo with special reference to coastal Eskimo of southwest Alaska. Based on archival sources and author's field work in 1964-65.
Download or read book An Annotated Ethnohistorical Bibliography of the Nushagak River Region Alaska written by James W Vanstone and published by Legare Street Press. This book was released on 2022-10-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book Lake Minchumina Prehistory written by Charles Edgar Holmes and published by . This book was released on 1986 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral thesis revision. Defines a cultural sequence for the Lake Minchumina region in interior Alaska.
Download or read book Napaskiak written by Wendell H. Oswalt and published by . This book was released on 1965 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dog Team Doctor written by Eva Greenslit Anderson and published by . This book was released on 2013-10 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a new release of the original 1945 edition.
Download or read book Areal Geology of Alaska written by Philip Sidney Smith and published by . This book was released on 1939 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
