EBookClubs

Read Books & Download eBooks Full Online

EBookClubs

Read Books & Download eBooks Full Online

Book The Relationship Between Reproduction and Mortality in Triploid Crassostrea Virginica

Download or read book The Relationship Between Reproduction and Mortality in Triploid Crassostrea Virginica written by Joseph L. Matt and published by . This book was released on 2018 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unusual mortalities of cultured Crassostrea virginica in late spring have been reported from farms in the Chesapeake Bay from 2014 to 2017. None of the usual causes (e.g. disease, poor husbandry) were likely responsible, and mortalities occurred without clear signs of biological or physical stressors. Mortalities in the spring of 2014 were particularly high on over a dozen farms in Virginia, most of which were on the bayside of the Eastern Shore. Estimated losses were over 50%; however, mortalities only occurred within a four-week period between mid-May and early June. Farmers that had unusually high mortality in their crop were exclusively growing triploid oysters, which implicated triploidy as an important factor and even led to calling these events "triploid mortality." Many affected farmers were also growing a "northern cross," oysters made by crossing brood stock from New England to brood stock from Virginia, and relatively high fecundity was found in some triploid oysters sampled from these farms. It was hypothesized that the genetic contribution from the New England parent of the northern cross was causing aberrant gametogenesis in triploid oysters during the late spring, and that this caused triploid mortality. A controlled field test was conducted to evaluate this hypothesis and to further examine the role of genetics and gametogenesis in triploid mortality. to investigate the effect that ploidy and brood stock origin have on susceptibility to triploid mortality, four triploid and four diploid types of oysters, produced by crossing different combinations of brood stock of Virginia, Louisiana, and Maine origin, were deployed to three commercial oyster farms that experienced unusually high mortality in 2014, as well as to a control site lacking reports of unusual spring mortality. The survival and growth of oysters from each group were measured throughout the spring and summer of 2016. A mortality event (>20% mortality) was observed in late spring at one site. The mortality event was only associated with triploid groups, with cumulative mortality ranging from 12 to 24% among groups. Mortality in the "northern cross" was not especially high (23%). The effect that gametogenesis had on the mortalities was investigated by examining histological cross sections of triploid and diploid oysters from the site where triploid mortality occurred, as well as from the control site where there was no triploid mortality. Diploid oysters at the affected site became gravid and spawned earlier than diploid oysters at the control site. Gonad development in triploid oysters was abnormal and variable, so categories were developed for classifying gonad development in triploid oysters and making comparisons between sites. No obvious difference was observed in gonad development between triploid oysters at the two sites. Cross-sections from male triploids did not typically contain any spermatozoa, and cross sections from females usually contained only a few oocytes. Gonad development may not be strongly associated with triploid mortality, but the physiology associated with abnormal gametogenesis in triploid oysters could be a major contributing factor. More work is needed on the physiological consequences of gametogenesis in triploid oysters to explain triploid mortality.

Book The Reproductive System of the American Oyster Crassostrea Virginica Gmelin

Download or read book The Reproductive System of the American Oyster Crassostrea Virginica Gmelin written by Austina Kennedy and published by . This book was released on 1963 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The American Oyster Crassostrea Virginica

Download or read book The American Oyster Crassostrea Virginica written by Carol Ann Reeb and published by . This book was released on 1989 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The American Oyster Crassostrea Virginica Gmelin

Download or read book The American Oyster Crassostrea Virginica Gmelin written by Paul Simon Galtsoff and published by . This book was released on 1964 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Oceanic Abstracts

Download or read book Oceanic Abstracts written by and published by . This book was released on 1988 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Selection Hybridization and Genetic Engineering in Aquaculture

Download or read book Selection Hybridization and Genetic Engineering in Aquaculture written by Klaus Tiews and published by . This book was released on 1987 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book NOAA Technical Report NMFS

Download or read book NOAA Technical Report NMFS written by and published by . This book was released on 1984 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Journal of Shellfish Research

Download or read book Journal of Shellfish Research written by and published by . This book was released on 1987 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Oceanic Abstracts with Indexes

Download or read book Oceanic Abstracts with Indexes written by and published by . This book was released on 1988 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Marine Ranching

Download or read book Marine Ranching written by Ralph S. Svrjcek and published by . This book was released on 1992 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Proceedings of the Third World Fisheries Congress

Download or read book Proceedings of the Third World Fisheries Congress written by Bruce F. Phillips and published by . This book was released on 2003 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Hatchery Culture of Bivalves

Download or read book Hatchery Culture of Bivalves written by Michael M. Helm and published by Food & Agriculture Organization of the UN (FAO). This book was released on 2004 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual is a synthesis of current methodologies pertinent to the intensive hatchery culture of bivalve molluscs. It encompasses both the similarities and differences in approach in rearing clams, oysters and scallops in different climatic zones. All aspects of the culture process are described, together with basic considerations in choosing a site for hatchery development and in the design of a suitable facility. It also includes the post-hatchery handling of larvae in remote setting and also of spat in both land- and sea-based nurseries. This document is intended to assist both technicians entering the field as well as entrepreneurs researching investment opportunities in bivalve culture.