Ecological Archives E087-017-A1

Darren W. Johnson. 2006. Density dependence in marine fish populations revealed at small and large spatial scales. Ecology 87:319–325.

Appendix A. Summary of linear, mixed-effects regressions used to test for overall presence of temporal density dependence in mortality of juvenile rockfish.  Polynomial models were included to determine whether the relationship between mortality and density was significantly curvilinear, rather than linear. Data are presented for both the blue rockfish (Sebastes mystinus) and the KGB species complex (S. atrovirens, S. carnatus, and S. chrysomelas).

     
Value
SE
df
t value
P value
S. mystinus
Full model
Intercept
0.4871
0.68133
16
0.7149
0.485
   
Density
0.05973
0.04943
16
1.2084
0.2445
   
Density2
-0.0003
0.00071
16
-0.3519
0.7295
               
 
Reduced model
Intercept
0.641
0.501
17
1.267
0.222
   
Density
0.043
0.012
17
3.507
0.0027
               
KGB
Full model
Intercept
1.8588
0.48478
16
3.8343
0.0015
   
Density
0.1372
0.03805
16
3.6067
0.0024
   
Density2
-0.001
0.00041
16
-2.4221
0.0277
               
log(KGB)  
Intercept
2.533
0.437
17
5.78
<0.0001
   
log(density)
0.0489
0.012
17
3.97
0.001



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