Fish Population & Phoslock Treatments


The Lake experienced large swings in the fish population in 2015 and early first quarter of 2016. Noticeably, during 2015-16 there was an increase in the amount of bird population at the Lake. The current decrease in fish population is as a result of the ongoing Golden Algae blooms and the increase of predators. Since 2014 Golden Algae has been a presence in the Lake adversely impacting the fish population. The Golden Algae affects the fish through toxic exposure of prymnesin targeting their gills and causing the fish to suffocate. SAMLARC’s Lake Aquatic Specialist has advised that the current presence of Golden Algae makes stocking of the Lake unadvisable, therefore the scheduled spring fish stocking has been deferred.


SAMLARC’s efforts to mitigate Golden Algae in 2015 included 23 separate treatments totaling approximately 11,000 pounds of liquid copper algaecide. The treatments worked to temporarily reduce the algae counts; however, they were not effective in permanent elimination of the Golden Algae. Additionally, the fish population continues to be adversely impacted by the Golden Algae blooms. In considering the environmental impact of increasing the overall copper content of the water and the projected annual 2016 cost of $42,750, a decision was made to treat for surface algae only and to let the eco-system balance itself out for a period of months.


Following this “rest” period of four months approval was given to implement a new “Phoslock” water treatment for the purpose of reducing Free Reactive Phosphorus levels in the water. Phoslock is a natural clay that reduces the amount of Free Reactive Phosphorus that is a food source for algae. It is hoped that reducing the algae food source will result in lower algae cell counts, less fluctuation in the cell counts and reduced toxicity of the Golden Algae to create a more favorable eco-system for the fish population. This treatment will take up to four months or longer to evaluate and confirm the positive effects of the treatment in balancing the eco-system and creating a healt