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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Richard L. Pycha</dc:creator>
  <dc:date>1980</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Total mortality rates of lake trout (&lt;/span&gt;&lt;i&gt;Salvelinus namaycush&lt;/i&gt;&lt;span&gt;) of age VII and older from eastern Lake Superior were estimated from catch curves of age distributions each year in 1968&amp;ndash;78. The instantaneous rate of total mortality&amp;nbsp;&lt;/span&gt;&lt;i&gt;Z&lt;/i&gt;&lt;span&gt;&amp;nbsp;varied from 0.62 to 2.31&amp;ensp;in close synchrony with sea lamprey (&lt;/span&gt;&lt;i&gt;Petromyzon marinus&lt;/i&gt;&lt;span&gt;) wounding rates on lake trout. The regression of transformed&amp;nbsp;&lt;/span&gt;&lt;i&gt;Z&lt;/i&gt;&lt;span&gt;&amp;nbsp;on the index of lamprey wounding, accounted for over 89% of the variation in lake trout mortality (&lt;/span&gt;&lt;i&gt;r&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;&lt;span&gt;&amp;ensp;=&amp;ensp;0.893). An iterative method of estimating rates of exploitation&amp;nbsp;&lt;/span&gt;&lt;i&gt;u&lt;/i&gt;&lt;span&gt;, instantaneous rates of fishing mortality&amp;nbsp;&lt;/span&gt;&lt;i&gt;F&lt;/i&gt;&lt;span&gt;,&amp;nbsp;&lt;/span&gt;&lt;i&gt;K&lt;/i&gt;&lt;span&gt;&amp;nbsp;(a constant relating sample catch per unit effort to population size), instantaneous normal natural mortality rate&amp;nbsp;&lt;/span&gt;&lt;i&gt;M&lt;/i&gt;&lt;span&gt;, and instantaneous rate of mortality due to sea lamprey predation&lt;/span&gt;&lt;i&gt;L&lt;/i&gt;&lt;span&gt;&amp;nbsp;from the sample catch per unit effort and total catch by the fishery is presented. A second method using the results of a 1970&amp;ndash;71 tagging study to estimate the mean&amp;nbsp;&lt;/span&gt;&lt;i&gt;F&lt;/i&gt;&lt;span&gt;&amp;nbsp;in 1970&amp;ndash;77 yielded closely similar results to the above and is presented as corroboration. The estimates of&amp;nbsp;&lt;/span&gt;&lt;i&gt;u&lt;/i&gt;&lt;span&gt;,&amp;nbsp;&lt;/span&gt;&lt;i&gt;F&lt;/i&gt;&lt;span&gt;, and&lt;/span&gt;&lt;i&gt;M&lt;/i&gt;&lt;span&gt;&amp;nbsp;appear to be reasonable.&amp;nbsp;&lt;/span&gt;&lt;i&gt;F&lt;/i&gt;&lt;span&gt;&amp;nbsp;ranged from 0.17&amp;ensp;in 1974 to 0.42&amp;ensp;in 1969 and&amp;nbsp;&lt;/span&gt;&lt;i&gt;M&lt;/i&gt;&lt;span&gt;&amp;nbsp;was estimated at 0.26.&amp;nbsp;&lt;/span&gt;&lt;i&gt;L&lt;/i&gt;&lt;span&gt;&amp;nbsp;varied from 0.21&amp;ensp;in 1974 to 1.70&amp;ensp;in 1968. Management implications of various policies concerning sea lamprey control, exploitation, and stocking are discussed.&lt;/span&gt;&lt;i&gt;Key words&lt;/i&gt;&lt;span&gt;: lake trout, sea lamprey, lamprey control, mortality, predation, Lake Superior, fishery, management&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1139/f80-247</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>NRC Research Press</dc:publisher>
  <dc:title>Changes in mortality of lake trout (&lt;i&gt;Salvelinus namaycush&lt;/i&gt;) in Michigan waters of Lake Superior in relation to sea lamprey (&lt;i&gt;Petromyzon marinus&lt;/i&gt;) predation, 1968-78</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>