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Author: Frank Walter Weymouth Publisher: ISBN: Category : Clams Languages : en Pages : 688
Book Description
Commercially the Pismo clam (Tivela stultorum)ranks first in importance in California among the clams and third among all the mollusks, being exceeded only by the oyster and the abalone. A second reason for considering this species is that there has been such evidence of depletion as to lead to increasingly more stringent protective laws, all of which have been urged by the residents of the county in which the clam is most abundant. ... An accurate study of the cause and extent of this apparent diminution must await knowledge of at least the fundamental facts of the life history of this clam. ... The more important features are considered to be: the habits, enemies and mortality of the adult; the rate of growth and the factors affecting it; the age at certain significant periods, particularly at sexual maturity and at the time when the legal size is reached; the most common age of clams forming the commercial catch; the season of spawning and the productivity; and the habits, enemies and mortality of the young.
Author: Frank Walter Weymouth Publisher: ISBN: Category : Clams Languages : en Pages : 688
Book Description
Commercially the Pismo clam (Tivela stultorum)ranks first in importance in California among the clams and third among all the mollusks, being exceeded only by the oyster and the abalone. A second reason for considering this species is that there has been such evidence of depletion as to lead to increasingly more stringent protective laws, all of which have been urged by the residents of the county in which the clam is most abundant. ... An accurate study of the cause and extent of this apparent diminution must await knowledge of at least the fundamental facts of the life history of this clam. ... The more important features are considered to be: the habits, enemies and mortality of the adult; the rate of growth and the factors affecting it; the age at certain significant periods, particularly at sexual maturity and at the time when the legal size is reached; the most common age of clams forming the commercial catch; the season of spawning and the productivity; and the habits, enemies and mortality of the young.
Author: Frank W. Weymouth Publisher: Forgotten Books ISBN: 9780656158522 Category : Science Languages : en Pages : 126
Book Description
Excerpt from The Life-History and Growth of the Pismo Clam, Vol. 7: Tivela Stultorum Mawe Department of Commercial Fisheries and is to be considered as a report, containing recommendations (p. Transmitted through him to the Bou1d of Fish and Game Commissioners. It is also presented as a thesis to the Department of Zoology of Stanford University in partial fulfillment of the requirements for the degree of doctor of philosophy. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Author: James Nybakken Publisher: ISBN: Category : Clam fisheries Languages : en Pages : 0
Book Description
Three aspects of the ecology of Pismo clams (Tivela stultorum) were investigated in Monterey Bay, California: distribution, reproduction cycle, and age and growth. Pismo clam populations were found to be restricted to bay areas between the Salinas River and Santa Cruz. Highest densities recorded were intertidal, and subtidal clam beds were few and with low densities. Most clams appeared randomly dispersed, and different size classes did not show a vertical separation. The presence and absence of clams were shown to be correlated with beach slope and grain size. Pismo clams mature in their second year in Monterey Bay, and the primary spawning time is in September and October. The growth rate is more rapid in young clams and varies throughout the year in all size classes but is most rapid in the summer and fall.