Scanning electron micrograph of BioBullets (scale bar = 100 microns). - Reprinted with permission from Environmental Science & Technology (Vol. 40, No. 3, p. 977). Copyright (2006) American Chemical Society

Scanning electron micrograph of a freeze-fractured BioBullet reveals a cubic crystal of potassium chloride within a vegetable oil matrix (scale bar = 20 microns). -  Reprinted with permission from Environmental Science & Technology (Vol. 40, No. 3, p. 977). Copyright (2006) American Chemical Society.

Endoscopic photograph of BioBullets being transported along the ctenidial gill of a live zebra mussel. Reprinted with permission from Environmental Science and Technology (Vol. 40, No. 3, p. 977). Copyright (2006) American Chemical Society.

At the request of Dr. David Kennedy, Quality Assurance officer at the U.S. Geological Survey’s Upper Midwest Environmental Sciences Center (UMESC), La Crosse Fishery Resources Office fishery biologist Mark Steingraeber recently completed the peer-review of two Quick Response Program study plans prepared by UMESC colleagues. 

The purpose of one study is to evaluate the relative sensitivity of zebra mussels (an invasive aquatic nuisance species) and black sandshell mussels (a representative native species) when exposed in the laboratory to BioBullets, a microencapsulated formulation of a salt (potassium chloride) that is particularly toxic to freshwater mussels. 

The outcome of this review was a recommendation to conduct tests with equal numbers of mussels of both species and with individuals of similar wet tissue weights.  This should prevent the collection and analysis of potentially problematic data that could result from the use of different numbers and sizes of mussels in test systems. 

The purpose of the second study is to compare the effectiveness of traditionally used Heath tray incubators to moist air incubators in the development of lake trout eggs to the eyed-stage, as well as to determine whether lowered incubation temperatures may increase fry production. 

The outcome of this review was a recommendation to include the use of an additional moist air incubation system to accommodate a third test treatment maintained at a cold temperature (4-7 C).  This should prevent the potential interaction of two test variables (i.e., incubation system x temperature) that may confound efforts to determine the independent impact of each variable on egg viability among different strains of lake trout.  If the results of these pending studies are successful, new and effective tools may become available to help combat zebra mussels and aid efforts to recover imperiled native mussels and fish.