Effects of stocked trout on stream invertebrate communities

Abstract:

Brown trout (Salmo trutta) are commonly stocked in streams and rivers worldwide to enhance recreational fisheries, but this practice can adversely impact other organisms in these ecosystems. We used nonmetric multi-dimensional scaling ordinations to evaluate the response of the invertebrate community to trout stocking in two streams in New York State. Most importantly, we used estimates of trout population mortality (natural and harvest mortality rates) to inform the timeframe within which the invertebrate response was evaluated because the potential impact of trout stocking is highly dependent on the abundance of stocked trout. We found that although brown trout are stocked at greater densities than native brook trout (Salvelinus fontinalis) the mortality rate of stocked trout was high (0.15 daily mortality rate which corresponds to 99.9% annual mortality), thus predatory impacts of fish upon invertebrates were likely to be pulsed and could only occur within a short temporal period. Despite the high mortality rate of stocked brown trout, we found a significant multivariate divergence of invertebrate community structure within two months of trout stocking in both streams.

Año de publicación:

2017

Keywords:

• Non-metric multidimensional scaling
• macroinvertebrates
• community structure
• Trout stocking
• Introduced fish
• Freshwater streams

Fuente:

scopus