Bulletin Of The United States Bureau Of Fisheries 1917 1918 Vol 36 Classic Reprint

Author : Hugh M. Smith
Publisher : Forgotten Books
ISBN 13 : 9780267906093
Total Pages : 306 pages
Book Rating : 4.9/5 (6 download)

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Download or read book Bulletin of the United States Bureau of Fisheries, Vol. 37 written by Hugh M. Smith and published by Forgotten Books. This book was released on 2018-02-06 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Bulletin of the United States Bureau of Fisheries, Vol. 37: 1919-1920 It remained, therefore, for Gilbert (1913) to give us the first accurate description of the general features of the life history Of the chinook salmon in his paper, The Age at Maturity of the Pacific Coast Salmon Of the genus Oncorhynchus. In this he shows, among other things, that: (a) The chinook, or king, salmon spawn normally either in the fourth, fifth, Sixth, or seventh year, the females more frequently in the fourth year; (b) the grilse are exclusively males and are of two sizes, representing two and three year fish; (0) the young may migrate as fry soon after hatching, or may remain in the stream until their second spring, migrating as yearlings; and (d) among the fish Of any given age, the larger specimens will be those which migrated seaward as fry, although these do not attain the average stature Of those fish, one year older, which migrated as yearlings. In a recent paper Fraser (1917) has verified some of Gilbert's findings and has extended the study to the spring salmon found in the Straits Of Georgia. He has worked out quite conclusively the rate of growth during the life in the sea and also the time Of formation of the winter check. The present study is a continuation Of that begun by Gilbert, and the results thus far have been in perfect agreement with his, although the material has been much more abundant and diverse. The outline of the life history of the chinook as given by him may be almost indefinitely extended, but it seems most unlikely that results maybe Obtained which are not in agreement with his original conclusions. At the beginning of this investigation it was supposed that an examination of the adult scales would give the data necessary for an understanding of the life history. Most Of the summer and autumn Of 1914 was, therefore, spent on the Columbia River col leeting scales and data from adult fish. Small series Of young, seaward migrants, were also taken at Astoria and Ilwaco, at the lower end of the Columbia estuary. Several collections of adult scales taken at spawning stations on various tributaries of the Columbia and Sacramento Rivers and collections of yearling chinooks made at Baird, Calif, were available for study through the courtesy Of Dr. C. H. Gilbert. Access was also had to a collection of young migrants from the Sacramento River through the kindness of N. B. Scofield, of the California Fish and Game Commission. These various collections were studied during the winter and spring of 1914 - 15. It was possible to verify the main conclusions reached by Gilbert as follows (1) The scales present two types of nuclear growth - one, the stream type, indicating that the fish migrated to the ocean after spending one year in fresh water, and the other, the sea type, indi cating that the fish migrated as a fry; (2) the chinobk may reach maturity at any time between the second and the seventh year. Those maturing in the second or third year are exclusively males. The prevailing ages at which maturity is reached by the chi nooks Of the Columbia River are 4 and 5 years, although fish in their sixth year are fairly common. Specimens maturing in their seventh year are very rare. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com