Factors related to the distribution and abundance of brown and rainbow trout in New Zealand clear‐water rivers

Abstract

Brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) populations at 157 riverine sites throughout New Zealand were divided into groups based on species, size, and abundance. The groups were examined to determine significant differences in hydrological, water quality, water temperature, biological, in-stream habitat, and catchment variables between groups. A discriminant model was developed with nine environmental factors which correctly classified 72% of a subset of 65 sites. Fish species distribution was related to climatic (water temperature), geographical, and hydrological factors, whereas fish abundance was determined by factors relating to flow variability, river gradient, in-stream habitat, and the presence of lakes in the catchment.

Characterisation and classification of benthic invertebrate communities in 88 New Zealand rivers in relation to environmental factors

“…data). This indicates that the data provide a reasonable estimate of overall invertebrate density for use in related studies on periphyton (Biggs 1990) and trout (Jowett 1990).…”

“…1); (2) covered a wide range of catchment types and land use; (3) covered most of the range of water quality conditions present at sites lacking significant upstream point-discharges; (4) had reliable hydrological records of >10 years; (5) included 43 of the 91 sites in a parallel study on trout (Jowett 1990); and (6) included 88 of the 101 sites in concurrent studies on water chemistry , water clarity , and periphyton (Biggs 1990) (the remaining 13 sites did not meet the baseflow (<median flow) sampling criterion at the scheduled time of sampling). The sites included 15 "lowland" rivers (mean catchment elevation (ELEV_C) < 300 m), 35 "foothill" rivers (ELEV_C 300-600 m), and 38 "upland" rivers (ELEV..C > 600 m).…”

Influence of macrohabitat preferences on the distribution of European brook and river lampreys: Implications for conservation and management

“…Parameters that reflect the river hydrology were also inputted in the model. Variation in flow has been identified as an important determinant of the biological character of rivers and streams (Poff, 1997), and can successfully predict a range of biological features, including the distributions of individual fish species (Jowett, 1990;Poff et al, 1997;Richter et al, 2003) and community structure of fish (Poff and Allan, 1995). Because of the temporary regime of the majority of Portuguese rivers, flow is an important variable in the distribution of freshwater fishes.…”

Strategies for conserving native salmonid populations at risk from nonnative fish invasions: tradeoffs in using barriers to upstream movement

“…Establishment of a nonnative salmonid population will depend on both environmental resistance (habitat suitability) and "biotic resistance" by native species, as well as chance events (Moyle and Light 1996). Habitat suitability for native and nonnative salmonids in streams is often governed by temperature regime (Meisner 1990, Rahel and Nibbelink 1999, Harig and Fausch 2002, Dunham and others 2003a, flow regime (Jowett 1990, Jager and others 1999, Strange and Foin 1999, Fausch and others 2001, stream size Nibbelink 1999, Rieman andothers 1999), habitat factors correlated with gradient (Fausch 1989, Adams 1999, and stream productivity (Kwak and Waters 1997). Because many of these factors influence fish at thresholds, measurements across a wide range of each variable often show that establishment is relatively predictable from simple physiological tolerances (see…”