Something's fishy: the effects of non-native rainbow trout farming on Neotropical cloud forest streams

Methods

Summary

A minimum of five trout farms located throughout the cloud forests near the Reserva Las Gralarias in Mindo, Ecuador will be studied.  Each trout farm will be characterized using available information including trout feed protein content, stream slope and discharge relative to effluent discharge.  At each farm, one site upstream (control) will be compared to a site at the farm outflow, and at least one site downstream (~150 m) to quantify recovery, should an impact be detected. Additional sites can be added to trace recovery more thoroughly as time permits. Parameters to be quantified at each sample site include temperature, total suspended solids, turbidity, pH, total alkalinity, total hardness, conductivity, DO, BOD, and concentrations and loading rates for ammonia, nitrate, ortho-phosphate and total phosphorus, as listed in Boaventura, et al., (1997). Parameters such as pH, temperature, and DO can be measured in situ, while additional chemical parameters will be sent to a laboratory for testing.  Nutrient grab samples will be collected 1 time per site (n=15 per nutrient)

Macroinvertebrate population samples (quantitative triplicate Surber samples, plus 1 qualitative kick sample) will be collected at each site and preserved in ethanol to be identified later in the laboratory. Samples will be identified to the lowest possible taxonomic level before being analyzed using a variety of metrics (FFG, EPT, etc.) (Barbour, et al.  EPA, 1999). 

Ten cotton strips will be deployed at each sampling site as a measure of ecosystem processes.  Cotton strip preparation, deployment, and analysis will follow Tiegs et al. (2013).  In short, 130 cotton strips will be prepared from Fredrix-brand unprimed 12-oz. heavy-weight cotton fabric, Style #548.  10 strips will be evenly spaced along a 1-m length of nylon cord and secured to the river bottom in a location representative of the sample zone. Five strips will be randomly removed after 14 days of incubation and the remainder will be removed after a total of 28 days incubation.  Upon removal, strips will be submerged in 80% ethanol for approximately 30 seconds and gently brushed to remove loosely attached sediment and biofilm. In the lab, strips will be dried at 40 C and stored with a desiccant until processing at the University of Western Ontario, ON, Canada. At Western, a tensiometer will be used to measure temperature loss.