1. Home
  2. Items
  3. Fish community structure associated with bank stabilization in the metals-contaminated...
PDF

Fish community structure associated with bank stabilization in the metals-contaminated lower Coeur d'Alene River, Idaho Item Info

Fish sampling and habitat assessment were conducted at 24 sites in the lower 54 km of the Coeur d'Alene River, Idaho in 2005 and 2006 to I) characterize four shoreline habitat types-- failing banks (FB), riprap (RR), riprap with vegetation (RR V), and vegetation (V)--according to ranked and quantifiable habitat variables, 2) assess differences in relative fish abundance (catch-per-unit effort; CPUE), species diversity, and community composition associated with the four shoreline habitat types, two sections (upstream and downstream), and three seasons (summer, spring, fall), 3) assess the relationships between relative fish abundance and habitat variables, and 4) assess the relationship between relative fish abundance and a) depth of riprap structure and b) riprap rock diameter. The four habitat types differed significantly in habitat characteristics based on Rapid Bioassessment Protocols (RBP) scores (F=5.73, P<0.001). All four habitat types scored poor or marginal in substrate/available cover, pool variability, sediment deposition, and riparian zone width. Relative fish abundance as measured by CPUE at stabilized (RR and RR V) shorelines was consistently higher than at unstabilized (FB and V) shorelines among all seasons. Relative fish abundance was not significantly different between stabilized and unstabilized habitat types for gillnetting (F= 1. 9 5, P=0.167), but was significantly higher at stabilized than unstabilized habitats for electrofishing (F=5.66, P=0.020). Differences in species diversity were only evident between sections, not among habitat types or seasons. Fish community differences were apparent among habitat types as well as between sections and among seasons. Brown bullhead Ameirus nebulosus, northern pike Esox lucius, and pumpkinseed Lepomis gibbosus were captured in significantly higher numbers at stabilized than unstabilized sites and longnose suckers Catostomus catostomus were captured in greater numbers at unstabilized than stabilized sites. Water temperature and spawn timing influenced fish abundance and composition in spring. Large diameter riprap supported a higher abundance of fish than did smaller diameter riprap. Overall, stabilized shorelines on the lower Coeur d'Alene River were not found to be adversely affecting overall fish relative abundance, diversity, and species composition under the existing conditions of a low percentage of banks stabilized with riprap (2.5%). Instead, stabilized shorelines provided beneficial habitat in a river system with low quality and diversity of available habitats. This result should not be predicted, however, to apply as increasingly high percentages of the river bank are stabilized, and loss of river function occurs. Data from the above sampling were also analyzed to assess possible impact of piscivores (smallmouth bass Micropterus dolomieui, northern pikeminnow Ptychocheilus oregonensis, and northern pike) on native salmonids, especially Westslope cutthroat trout Oncoryhynchus clarki lewisi. The objectives were to 1) evaluate and quantify salmonid use of stabilized and unstabilized shoreline habitats by season and river section, 2) evaluate and quantify piscivorous species use of stabilized and unstabilized shoreline habitat by season and river section, and 3) determine if an overlap exists between salmonid and piscivore use of stabilized and unstabilized shoreline habitats by season and river section. In all, 81 salmonids were captured, or 2% of the total fish catch. Salmonid catch in the lower river was greatest during spring when water temperatures were low and juveniles were outmigrating to Lake Coeur d'Alene. No significant differences in salmonid catch were evident between stabilized and unstabilized habitats (x2=0.064, P=0.800), though juvenile wests lope cutthroat trout showed some affinity for stabilize areas with I 0 out of 12 individuals captured at these sites. In all, 670 piscivores were captured, or 19% of the total fish catch. Piscivore catch was significantly lower in spring, when salmonid numbers were highest, than in fall and summer, when salmonid numbers were lowest (x2=17.465, P<O.OOl). Overall, piscivores were not captured in significantly different numbers at stabilized and unstabilized habitats (x2=0.243, P=0.622); however, northern pike (N=22) were captured in significantly higher numbers at stabilized habitats. The overall effects of habitat type on salmonid and piscivore overlap were not clear. Based on the data available, season seems more important than habitat in affecting salmonid and piscivore impacts. Specific studies are outlined that need to be conducted for a clearer understanding of the relation between salmonids and potential predation from piscivores in the lower river. In comparison of catches between the two gears (gillnetting and electro fishing), species composition (x2=831.46, P<O.OO 1) and length selectivity (t=3 7 .86, P<O.OO 1) were significantly different. Electro fishing captured a greater numbers of individuals (N=2,915) than gillnetting (N=596), but individuals were much smaller for electrofishing (mean length 96 mm) than for gillnetting (mean length 331 mm). Gillnets more readily captured longnose suckers and largescale suckers Catostomus macrocheilus (50% of total catch), whereas electro fishing captured larger numbers of yellow perch Perea flavescens and pumpkinseed (54% of total catch). The use of these two gears together provided a more representative sample of the fish community than either gear could have provided alone.

View on Timeline View on Map Download PDF
Title:
Fish community structure associated with bank stabilization in the metals-contaminated lower Coeur d'Alene River, Idaho
Authors:
Gidley, Catherine A.
Date Created (ISO Standard):
2008-01
Description:
Fish sampling and habitat assessment were conducted at 24 sites in the lower 54 km of the Coeur d'Alene River, Idaho in 2005 and 2006 to I) characterize four shoreline habitat types-- failing banks (FB), riprap (RR), riprap with vegetation (RR V), and vegetation (V)--according to ranked and quantifiable habitat variables, 2) assess differences in relative fish abundance (catch-per-unit effort; CPUE), species diversity, and community composition associated with the four shoreline habitat types, two sections (upstream and downstream), and three seasons (summer, spring, fall), 3) assess the relationships between relative fish abundance and habitat variables, and 4) assess the relationship between relative fish abundance and a) depth of riprap structure and b) riprap rock diameter. The four habitat types differed significantly in habitat characteristics based on Rapid Bioassessment Protocols (RBP) scores (F=5.73, P<0.001). All four habitat types scored poor or marginal in substrate/available cover, pool variability, sediment deposition, and riparian zone width. Relative fish abundance as measured by CPUE at stabilized (RR and RR V) shorelines was consistently higher than at unstabilized (FB and V) shorelines among all seasons. Relative fish abundance was not significantly different between stabilized and unstabilized habitat types for gillnetting (F= 1. 9 5, P=0.167), but was significantly higher at stabilized than unstabilized habitats for electrofishing (F=5.66, P=0.020). Differences in species diversity were only evident between sections, not among habitat types or seasons. Fish community differences were apparent among habitat types as well as between sections and among seasons. Brown bullhead Ameirus nebulosus, northern pike Esox lucius, and pumpkinseed Lepomis gibbosus were captured in significantly higher numbers at stabilized than unstabilized sites and longnose suckers Catostomus catostomus were captured in greater numbers at unstabilized than stabilized sites. Water temperature and spawn timing influenced fish abundance and composition in spring. Large diameter riprap supported a higher abundance of fish than did smaller diameter riprap. Overall, stabilized shorelines on the lower Coeur d'Alene River were not found to be adversely affecting overall fish relative abundance, diversity, and species composition under the existing conditions of a low percentage of banks stabilized with riprap (2.5%). Instead, stabilized shorelines provided beneficial habitat in a river system with low quality and diversity of available habitats. This result should not be predicted, however, to apply as increasingly high percentages of the river bank are stabilized, and loss of river function occurs. Data from the above sampling were also analyzed to assess possible impact of piscivores (smallmouth bass Micropterus dolomieui, northern pikeminnow Ptychocheilus oregonensis, and northern pike) on native salmonids, especially Westslope cutthroat trout Oncoryhynchus clarki lewisi. The objectives were to 1) evaluate and quantify salmonid use of stabilized and unstabilized shoreline habitats by season and river section, 2) evaluate and quantify piscivorous species use of stabilized and unstabilized shoreline habitat by season and river section, and 3) determine if an overlap exists between salmonid and piscivore use of stabilized and unstabilized shoreline habitats by season and river section. In all, 81 salmonids were captured, or 2% of the total fish catch. Salmonid catch in the lower river was greatest during spring when water temperatures were low and juveniles were outmigrating to Lake Coeur d'Alene. No significant differences in salmonid catch were evident between stabilized and unstabilized habitats (x2=0.064, P=0.800), though juvenile wests lope cutthroat trout showed some affinity for stabilize areas with I 0 out of 12 individuals captured at these sites. In all, 670 piscivores were captured, or 19% of the total fish catch. Piscivore catch was significantly lower in spring, when salmonid numbers were highest, than in fall and summer, when salmonid numbers were lowest (x2=17.465, P<O.OOl). Overall, piscivores were not captured in significantly different numbers at stabilized and unstabilized habitats (x2=0.243, P=0.622); however, northern pike (N=22) were captured in significantly higher numbers at stabilized habitats. The overall effects of habitat type on salmonid and piscivore overlap were not clear. Based on the data available, season seems more important than habitat in affecting salmonid and piscivore impacts. Specific studies are outlined that need to be conducted for a clearer understanding of the relation between salmonids and potential predation from piscivores in the lower river. In comparison of catches between the two gears (gillnetting and electro fishing), species composition (x2=831.46, P<O.OO 1) and length selectivity (t=3 7 .86, P<O.OO 1) were significantly different. Electro fishing captured a greater numbers of individuals (N=2,915) than gillnetting (N=596), but individuals were much smaller for electrofishing (mean length 96 mm) than for gillnetting (mean length 331 mm). Gillnets more readily captured longnose suckers and largescale suckers Catostomus macrocheilus (50% of total catch), whereas electro fishing captured larger numbers of yellow perch Perea flavescens and pumpkinseed (54% of total catch). The use of these two gears together provided a more representative sample of the fish community than either gear could have provided alone.
Subjects:
fish aquatic habitats biological sampling
Location:
Coeur d'Alene River
Latitude:
47.51
Longitude:
-116.15
Collection:
Coeur d'Alene Basin
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
wbv
Date Digitized:
2012

Contact us about this record

Source
Preferred Citation:
"Fish community structure associated with bank stabilization in the metals-contaminated lower Coeur d'Alene River, Idaho", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-cda_gidley_2008.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
« Previous Back to Browse Next »