Micheal Masser, Extension Fisheries Specialist, Texas A&M University
Aquatic plants can be problems in both aquaculture and recreational ponds. In private impoundments, almost any aquatic plant can be invasive because of the pond’s shallow water depths and accumulation of nutrients over time (i.e., high fertility). In all ponds, excessive algae blooms and aquatic macrophytes (rooted vegetation) can cause low dissolved oxygen problems that can lead to fish stress and even mortality. In aquaculture ponds, macrophytes hinder feed access, prevent seining activities, reduce water circulation, and may harbor pests such as snails, snakes, etc. Many macrophytes significantly increase water loss from the pond through evapotranspiration. Aquatic macrophytes are efficient utilizers of available nutrients, especially phosphorus, and may therefore make it difficult to establish a healthy phytoplankton bloom. The physical presence of aquatic plants may slow water movement within the pond allowing suspended sediments to settle. This reduction of turbidity may lead to increased predation by birds and otters and further exacerbate vegetation problems. In recreational ponds, macrophytes can reduce access to forage (i.e., food) by desirable species (e.g., largemouth bass), leading to poor fish growth and stunting. Total control of aquatic vegetation is often impossible, but with a well-designed integrated pest management approach to the problem, reasonable control of nuisance plants can be achieved.
Greg Lutz, Extension Professor, Louisiana State University
One of the most useful websites for identifying aquatic plants is AquaPlant
For more information please visit your Regional Aquaculture Center
Managing Iowa Fisheries (pdf)