Author : David Barto
Publisher :
ISBN 13 :
Total Pages : 222 pages
Book Rating : 4.:/5 (576 download)
Book Synopsis Assessing the Production of Sockeye Salmon (Oncorhynchus Nerka) at Chilkat Lake, Southeast Alaska, Using Current Trophic Conditions and the Paleolimnologic Sediment Record by : David Barto
Download or read book Assessing the Production of Sockeye Salmon (Oncorhynchus Nerka) at Chilkat Lake, Southeast Alaska, Using Current Trophic Conditions and the Paleolimnologic Sediment Record written by David Barto and published by . This book was released on 2004 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Anadromous sockeye salmon are the only Pacific salmon that require an extensive rearing period in a lake environment. Recent studies suggest changes in lake nutrient inputs are directly related to the magnitude of annual spawning populations (escapement), and can be quantified by sediment stable isotope analysis of nitrogen 15N). Marine nitrogen supplied by returned salmon is enriched in 15N relative to the freshwater nitrogen, which is derived from atmospheric N2 (ð15N=0 0/00). Recent (1987-1996) limnological investigations of Chilkat Lake, Alaska, matched to brood year escapement estimates, indicate that sockeye marine-derived phosphorus and nitrogen contributed up to 87% and 20%, respectively, of the lake nutrient pool. Since salmon populations fluctuate annually, the resulting marine derived nutrient (MDN) inputs and ð15N also fluctuate. Sedimentary ð15N is positively correlated (r2=0.8605, p=0.0076, df=5) with observed escapement. Additionally, ð15N is positively related to lake paleoproductivity and inversely correlated with high concentrations of CaCO3 and glacial silt. The frequency and duration of these CaCO3 inputs are believed to be the result of climate related glacial meltwater intrusions from the Tsirku River. Thus, fluctuations in MDN can be shown to influence the overall sockeye salmon production at Chilkat Lake by controlling lake productivity"--Leaf iii.