Skip to main content

Advertisement

Table 4 Selectivity index (Ivlev) of body size prey (mm) in the diet of rainbow trout ( Oncorhynchus mykiss )

From: Selective foraging by non-native rainbow trout on invertebrates in Patagonian streams in Argentina

Early autumn Late winter Late spring Late summer
NyF CVA NyF CVA NyF CVA NyF CVA
  Size Ivlev   Size Ivlev   Size Ivlev   Size Ivlev   Size Ivlev   Size Ivlev   Size Ivlev   Size Ivlev
Chilina patagonica S 4.87 1 Chilina patagonica S 4.87 1 Hyalella araucana S 2.85 −1 Aubertoperla illiesi S 2.05 −1 Hyalella araucana S 1.35 --- Chilina patagonica S 1.34 --- Andesiops torrens S 1.80 −1 Chilina patagonica S 5.94 ---
  M 9.74 ---   M 9.74 ---   M 5.70 −0.89   M 4.10 −0.76   M 2.70 −1   M 2.68 ---   M 3.60 −0.61   M 11.8 1
  L 14.61 −1   L 14.6 −1   L 8.55 −0.77   L 6.15 −0.09   L 4.05 1   L 4.02 −0.96   L 5.40 0.63   L 17.8 −1
Hyalella araucana S 2.22 1 Antactoperla michaelseni S 3.34 −0.44 Aubertoperla illiesi S 1.78 −1 Meridialaris chiloeense S 2.47 −1 Limnoperla jaffueli S 2.00 --- Brachysetodes sp. S 1.91 −1 Parasericostoma ovale S 2.77 −1 Antactoperla michaelseni S 1.65 ---
  M 4.44 −0.37 Antactoperla michaelseni M 6.68 0.59   M 3.56 −0.96   M 4.94 −0.95   M 4.00 0.57   M 3.82 −0.95   M 5.57 −0.55   M 3.30 −0.44
  L 6.66 1   L 10.02 0.51   L 5.34 0.68   L 7.41 −0.65   L 6.00 0.57   L 5.73 −0.65   L 8.31 −0.55   L 4.95 1
Notoperlopsis femina S 4.14 −0.75 Pelurgoperla personata S 2.05 −1 Limnoperla jaffueli S 2.6 −1 Smicridea annulicornis S 3.65 --- Penaphlebia chilensis S 4.31 −069 Smicridea annulicornis S 4.47 --- Smicridea annulicornis S 1.74 --- Pelurgoperla personata S 1.78 ---
  M 8.28 0.43   M 4.10 −0.95   M 4.72 −0.94   M 7.30 −0.82   M 8.62 −0.67   M 8.94 −0.16   M 3.48 0.85   M 3.56 ---
  L 12.42 1   L 6.15 1   L 7.08 0.83   L 10.9 1   L 12.9 −1   L 13.4 −0.16   L 5.22 0.85   L 5.34 −0.95
Nousia delicata S 2.94 −1 Meridialaris chiloeense S 2.67 −1 Penaphlebia chilensis S 2.87 −1 Simuliidae S 2.00 −1 Parasericostoma ovale S 3.74 −0.75        Nousia crena S 2.27 −1
  M 5.88 0.58   M 5.34 −0.96   M 5.74 −1   M 4.00 −0.91   M 7.48 0.38         M 4.57 −1
  L 8.82 1   L 8.01 −0.72   L 8.61 −0.14   L 6.00 −0.56   L 11.2 −0.87         L 6.81 0.60
Andesiops torrens S 2.05 −0.22 Andesiops torrens S 2.45 --- Parasericostoma ovale S 3.42 −1 Paratrichocladius S 1.78 --- Smicridea annulicornis S 3.67 1        Andesiops torrens S 2.05 ---
  M 4.10 −0.03   M 4.90 ---   M 6.84 0.05   M 3.56 ---   M 7.34 ---         M 4.10 −1
  L 6.15 1   L 7.35 −0.68   L 10.2 0.71   L 5.34 0.91   L 11.0 −1         L 6.15 1
Parasericostoma ovale S 2.94 −0.95 Parasericostoma ovale S 2.14 --- Athericidae S 4.45 ---     Paratrichocladius sp. S 1.78 ---        Hudsonema flaminii S 2.14 −1
  M 5.88 −0.14   M 4.28 ---   M 8.90 −0.78      M 3.56 −0.92         M 4.28 ---
  L 8.82 −0.21   L 6.42 −0.92   L 13.3 1      L 5.34 −0.69         L 6.42 1
Hudsonema flaminii S 1.40 --- Hudsonema flaminii S 2.22 −0.97 Simuliidae S 2.31 ---              Brachysetodes sp. S 2.27 −1
  M 2.80 −0.60   M 4.44 −0.85   M 4.62 0.83               M 4.54 −1
  L 4.20 −0.25   L 6.66 −0.35   L 6.93 1               L 6.81 −0.91
Brachysetodes sp. S 1.29 --- Brachysetodes sp. S 1.65 −0.61                 Neoatopsyche brevispina S 2.89 −1
  M 2.58 0.21   M 3.30 −1                  M 5.78 −1
  L 10.68 1   L 15.2 −1                  L 11.0 −0.97
Simuliidae S 1.84 −0.55 Smicridea annulicornis S 3.65 −1                 Smicridea annulicornis S 3.69 −1
  M 3.68 0.37   M 7.30 −0.88                  M 7.38 −0.17
  L 5.52 0.04   L 10.9 0.21                  L 11.0 0.13
Paratrichocladius S 1.78 --- Athericidae S 4.20 −1                 Simuliidae S 2.22 −1
  M 3.56 −0.39   M 8.40 −1                  M 4.44 −1
  L 5.34 4   L 12.6 −0.87                  L 6.66 1
    Simuliidae S2.09 −0.96                   
     M 4.18 −0.82                   
     L 6.27 −0.58                   
  1. From Nant y Fall (NyF) and Cabeza de Vaca (CVA) streams (Patagonia, Argentina) during the study period. Body size taxa absence was represented by ---. S, small size; M, medium size; L, large size.