Quantifying aquatic food web interactions in Lake Chelan ...
Quantifying aquatic food web interactions in Lake Chelan ...
Quantifying aquatic food web interactions in Lake Chelan ...
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<strong>Lake</strong> trout survival and population size<br />
• Survival rate determ<strong>in</strong>ed<br />
from age frequency of<br />
catch (Z ≈ 0.55, annual<br />
survival ≈ 58%)<br />
• Estimated annual<br />
harvest <strong>in</strong> Wapato Bas<strong>in</strong><br />
= 2000 to 3000 (A. Jones, pers.<br />
comm.)<br />
• Estimated m<strong>in</strong>imum age<br />
vulnerable to harvest at<br />
3.5 years (fork length =<br />
372 mm or 14 1/2”)<br />
• Population size<br />
estimated us<strong>in</strong>g Baranof<br />
catch equation (Shuter et al. 1998)<br />
Z<br />
− M<br />
Z<br />
−( Z )<br />
Catch<br />
t<br />
= (1 − e )<br />
where<br />
Z is the total mortality rate<br />
M is the natural mortality rate<br />
N t<br />
is the population at time t<br />
N<br />
Prelim<strong>in</strong>ary estimated<br />
size of Wapato Bas<strong>in</strong><br />
population<br />
= 13,959 to 20,939 lake<br />
trout (exclud<strong>in</strong>g age 0)<br />
t
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