The fish loss at the Barefoot West Lake is a very unfortunate event. Solitude Lake Management was on site Monday. Below is the report from Solitude Lake Management Regional Manager, Erin Stewart.
Erin Stewart reported:
Based on the measurements today, it appears that the lake has some low dissolved oxygen (DO) levels and elevated pH which is what likely killed the fish. These conditions are likely due to less than ideal baseline lake conditions (shallow, hot, no water exchange, high nutrients) that were exacerbated by an algae bloom.
- Significant numbers of dead fish found along western and southern shorelines
- Majority of the fish (~98%) were Gizzard Shad
- Gizzard shad can easily overpopulate a lake and are not a good food source after they are more than 4-5″
- Gizzard shad are more susceptible than other species to changes in water quality (high/low temps, low DO, etc)
- Most fish were of the same size/ age class – 5″ ~ 1 year old
- Very limited numbers of any game or desirable fish species – good news
- Algae bloom still present but less than observed last week.
- Dissolved oxygen concentrations low below the surface
- Aquatic life prefers 5.0mg/L or above
- ~10mg/L at the surface
- ~4mg/L at 1 m depth
- <1.0 mg/L at 2m or below
- pH ranged from 8.8-9.66
- pH higher than ideal for a freshwater ecosystem. Fish are likely to experience stress when the pH is above 9.0
- 24 buckets – ~600 lbs collected from shoreline areas and disposed of
- Difficult to access fish in the middle of lake and deeper areas.
- Many birds present – pelicans, cormorants, seagulls, turkey vultures – these birds should help have the fish “cleaned” up by the end of the week if not before.
Based on the onsite observations and measurements collected, it is likely that the physical conditions, algae bloom, and the hot dry weather led to low dissolved oxygen and high pH causing fish stress and loss.
As I mentioned, unfortunately, fish kills this time of year are common across the front range and country. Most of the time they are due to natural events from biological processes in the waterbody. But development, urbanization, agriculture, runoff and other human impacts play a role in the poor water quality feeding the lake.