Clearly, the removal of phytoplankton from the water column by zebra mussels has implications beyond the producer and primary consumer trophic levels. Many zooplankton and rotifers feed on phytoplankton. The extensive filtering of zebra mussels has also increased sunlight penetration, which encourages aquatic plant growth in many areas. The veligers are spewed into the water column where they freely float for 2-3 days. They then settle and attach themselves to any solid natural or humanmade substrate.
Juveniles can break away, generate new threads, and drift to new areas of attachment.
In contrast, native adult freshwater mussels in the United States do not have the ability to attach themselves to hard surfaces. The life span of adult zebra mussels ranges from 2 to 5 years. Limiting Factors Salinity, calcium, pH, temperature, and dissolved oxygen are limiting factors for the survival and growth of zebra mussels and can be used to determine the risk of infestation. Because these parameters can vary daily and seasonally and do vary spatially, the collection of measurements in several locations over an extended period of time is important for determining the extent of potential infestation. Assessments of infestation risk must be made in consideration of various factors, for example, frequency of access by boats from other water bodies, multiple fishing derbies, ease of boating access, and proximity to infested waters.