Remodel Operating Cold Water Trout Farm into Combination Cold Water/Cool Water Fish Farm, While Diversifying Production and Maintaining a Reduced Ecological and Energy Footprint

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2016: $15,000.00
Projected End Date: 01/30/2018
Grant Recipient: Wilderness Springs Inc. / The Trout Farm LLC
Region: North Central
State: Wisconsin
Project Coordinator:
Michael Foster
Wilderness Springs

Annual Reports


  • Animals: fish


  • Animal Production: aquaculture
  • Crop Production: water management
  • Education and Training: on-farm/ranch research
  • Energy: anaerobic digestion
  • Farm Business Management: feasibility study
  • Natural Resources/Environment: habitat enhancement
  • Pest Management: biological control
  • Production Systems: Aquaculture fish management
  • Sustainable Communities: new business opportunities



    Cold water remodel changes include: 

    1. Build an RAS type bio-filter into existing/operating trout rearing tank. The objective is to filter out ammonia nitrogen and increase production density (fish production) of downstream tanks.  Suspended solids by-pass plastic media bed is now constructed and bacteria beds are established.
    2. Reconfigure cold water ponds (reduce size) to make more productive. Reshape to reduce dead spots or deeper as required.  Additional spillway constructed and installed here.

    Cool water changes:

    1. Dig large pond and enlarge existing smaller trout ponds to become large area lagoons to grow perch.  Fabricate new flow control spillways for additional ponds created.  Another new spillway was installed August 2016.


    Cold water results: 

    The bio-filter is installed.  Needs a few more months for bacteria to grow and activate the filter function.


    Cool water results: 

    Started pond renovations required.  Installed new water spillway.  Now weather permitting, will do digging required to enlarge ponds for perch raising.

    Purchased some perch brood fish to obtain eggs to hatch and grow for this project.

    WORK PLAN FOR 2017

    2017 Cold water projects:

    Perform cold water, water quality analysis to measure how efficient a flow-through, RAS bio-filter can be in cold water application. Measure and record results.

    1. Was Ammonia Nitrogen reduction realized?
    2. If so, by how much?
    3. Did this process/install cause stress to fish raised downstream of bio-filter?

    2017 Cool water projects:

    1. The large pond drain structures are installed.  Next is to excavate the cool water ponds as planned. 
    2. Plan to hatch perch eggs and raise young perch as planned


    July 2016 we hosted Wisconsin Aquaculture Day (3rd Sat in July) at our Trout Farm. We had 40-45 people attend.  Throughout the day we explained what we are doing with our project and what we’re hoping our results will be.   Many did not have any idea of what the bio-filter would do so we explained that. 

    1. Does it digest organic waste?
    2. Does it remove Ammonia Nitrogen gas? If so, how much? 
    3. Observations were that bug larva in & around the bio-filter is creating some natural feed for downstream tanks.


    We are preparing presentations for Ag classes at 3 different High Schools. 

    Once we have more data we will write articles for the Wisconsin Aquaculture Association (WAA) newsletter, The Creel.  We also plan to give a presentation at the WAA conference and future annual Aquaculture Day events. 



    2017 Cold water projects:

    The bio-filter has been in place for several months, during which time the plastic media bed was established.  Water analyses were performed to measure the effect of the bio-filter.  Water checks included alkalinity, ammonia nitrogen, nitrate nitrogen, dissolved oxygen, carbon dioxide, temperature and pH.  Throughout the tests the average values for the following remain constant:

    • Alkalinity was at 3.2
    • Ammonia nitrogen was at 0.25
    • Nitrate nitrogen was at 0.05
    • Temperature was at 56°F
    • pH 7.5

    Water tests were conducted with air injection aeration both with air on and air off the bio-filter.  

    AIR OFF:  Values for dissolved oxygen were infeed 6.6 mg/l to outfeed 7.0 mg/l. The carbon dioxide levels were infeed 70 ppm to outfeed of 80 ppm. 

    AIR ON:  Values for dissolved oxygen were infeed 5.4 mg/l to outfeed of 6.9 mg/l  The carbon dioxide levels were infeed 125ppm to outfeed of 90 ppm

    The data suggests the aeration produced the most noticeable change.  The dissolved oxygen net increase was more than 3 fold.  The carbon dioxide retracted 35 ppm from what was an increasing 10 ppm average.  The aeration component of this model improved the dissolved oxygen level and reduced the carbon dioxide level.  The target of this bio-filter was to measure any drop in the ammonia nitrogen level; however, no significant drop was measured from inlet to outlet points.  The temperature at 56°F, appears to have slowed the bacterial action of the bio-filter.

    This process improved the water quality to the fish downstream due to the increase of dissolved oxygen level with the aeration on.

    In addition the installation of variable pond water structures allowed for increased gravity aeration in cold water remodel of existing ponds.


    Cool Water Projects:

    2017 Cool water projects:

    Excavated additional large cool water pond with its new water control structure.  This is located below existing cold water pond which is to be used for perch production. 

    Perch were stocked in cool water pond.  We observed some spawning activity, however, the perch ribbons failed to hatch.   We plan to continue future attempts to successfully spawn perch in this pond.  


    July 2017 we again hosted Wisconsin Aquaculture Day (3rd Sat in July) at our Trout Farm.  The attendance was down considerably from the previous year, we assume due to the weather that day.   Those that attended were interested to hear about our research project: What our results have proven thus far concerning digestion of organic waste, the ammonia nitrogen levels and the increase in bug larva.

    We gave a short summary presentation at the 2017 Wisconsin Aquaculture Assoc. Conference.  We have prepared a short article for an upcoming Creel (WAA Newsletter). 







    Project objectives:

    1. Remodel operating cold water trout farm into combination cold water/cool water fish farm.
    2. Improve and maintain and system with good water quality, positively impacting the environment.
    3. Create a system that will maximize profits by reducing water usage lowering energy costs.
    4. Provide high quality, healthy, uncontaminated fish to local consumers.
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.