Written by Ben German, Fisheries Biologist
Scientific inquiry is often the driving force behind innovation, and continuing to analyze and fine-tune our management strategies helps us deliver the best service possible to our clients. Fisheries managers often use fertilization (or productivity manipulation) to increase the biological productivity of a lake or pond. The increase in nutrient concentrations spurs algae production, resulting in increased biomass at ascending trophic levels of the food web. In other words, more food equals bigger fish. Fertilizing has been a proven strategy for quite some time, but recent insights into nutrient ratios, and how to properly manage them, is bringing consistency to the process of producing trophy Largemouth Bass.
The primary pond nutrients responsible for driving biological productivity are nitrogen and phosphorus (N & P). The ratio between these two important nutrients can help to determine the extent and type of biological productivity that results.
When it comes to increasing biomass to help grow fish, not all algal productivity is good. Oftentimes, when fertilizing a fishery, cyanobacteria (also known as blue-green algae) can become abundant. These microscopic algae can produce toxins that are harmful to fish, humans and other wildlife. One important characteristic some members of this undesirable group of algae share, that green algae do not, is the ability to fix atmospheric nitrogen. This means that so long as phosphorus is available, cyanobacteria can thrive, even if nitrogen is limiting.
By contrast, the desirable fish-growth-promoting green algae that fertilization seeks to propagate need an ample supply of nitrogen (in addition to phosphorus) in order to grow. By keeping the N:P ratio in the optimal range for green algae, cyanobacteria blooms can be minimized - even in a nutrient enriched environment, since with the proper N:P ratios the green algae have a much easier time competing with blue-green algae.
Establishing a sound monitoring program is key, as it provides the foundation for us to implement practices such as adding phosphorus, mitigating phosphorus or adding nitrogen as needed. To favor green algae further, if any cyanobacteria do pop up, SOLitude manages with targeted treatments designed to have minimal impact on the desirable green algae, helping to give green algae a competitive advantage.
Through research and experimentation, SOLitude fisheries professionals are learning to use this nutrient ratio as a tool instead of facing it as a challenge. With routine water quality monitoring, we can make calculated and informed adjustments aimed at ensuring optimal water quality conditions that favor green algae production. One of the ways we accomplish this is by observing traditional parameters such as dissolved oxygen, alkalinity and pH, in addition to key nutrient concentrations (nitrogen and phosphorus) and comparing these results with the observed algal species comprising the bloom over time. The ultimate goal of this management approach is the maintenance of a productive and healthy aquatic environment, optimized for beneficial algae, to promote growth of trophy Largemouth Bass.
Contact the experts at 888-480-LAKE (5253) for all of your lake, stormwater pond, wetland and fisheries management needs.
Ben German is a Fisheries Biologist based out of SOLitude’s Shrewsbury, MA office. He specializes in fisheries management, water quality monitoring and analysis, aquatic plant identification and the study of invertebrate communities. Ben earned a Bachelor’s degree in Fisheries and Aquaculture from SUNY Cobleskill, as well as a Master of Science degree in Lake Management from SUNY Oneonta. Prior to joining SOLitude, Ben spent a few years as a visiting professor at SUNY, teaching fisheries and environmental courses.
SOLitude Lake Management is a nationwide environmental firm committed to providing sustainable solutions that improve water quality, enhance beauty, preserve natural resources and reduce our environmental footprint. SOLitude’s team of aquatic resource management professionals specializes in the development and execution of customized lake, stormwater pond, wetland and fisheries management programs that include water quality testing and restoration, nutrient remediation, algae and aquatic weed control, installation and maintenance of fountains and aeration systems, bathymetry, shoreline erosion restoration, mechanical harvesting and hydro-raking, lake vegetation studies, biological assessments, habitat evaluations, and invasive species management. Services and educational resources are available to clients nationwide, including homeowners associations, multi-family and apartment communities, golf courses, commercial developments, ranches, private landowners, reservoirs, recreational and public lakes, municipalities, drinking water authorities, parks, and state and federal agencies. SOLitude Lake Management is a proud member of the Rentokil Steritech family of companies in North America.