Mary P. Henson | Geology Reports

USGS2022

Distribution of niclosamide following granular Bayluscide applications in lotic systems

The granular formulation of Bayluscide [Bayluscide 3.2% Granular Sea Lamprey Larvicide, granular Bayluscide (gB)] is applied in lentic and lotic systems to survey (assessment) and kill (treatment) larval sea lampreys ( Petromyzon marinus ; Linnaeus, 1758) in the Great Lakes basin. Granules are spread on the water surface, settle to the sediment surface, and dissolve. The potential risk of niclosamide exposure (2′,5-dichloro-4′-nitrosalicylanilide), the active ingredient of gB, to non-target organisms located downstream of survey plots, is a concern of partner agencies (state-level natural resource departments, U.S. Fish and Wildlife Service Ecological Services, and Fisheries and Oceans Canada Species at Risk Branch). Spatiotemporal distribution of niclosamide in the water column and sediment was evaluated in and downstream of five larval survey plots in two rivers following the application of gB. Water samples were collected at 0.25, 2, 4, 6, 8, and 24 h from three depths in the water column (10 cm above the sediment, ½ the water column depth, and the water surface) at three locations inside each survey plot, and 1 meter upstream from three sediment sample grids positioned 10, 30, and 100 m downstream. Sediment samples were collected from inside the grids at 0.25, 2, 4, 6, 8, and 24 h, and from inside the survey plots, 8 and 24 h after gB application. Niclosamide was detected in the sediment and water at all sample locations. From 2 to 24 h after application, average water concentrations 1) varied between study sites, 2) decreased from the survey plots to 100 m downstream, 3) varied by depth in the water column, and 4) decreased over time. Average sediment concentrations varied by distance downstream and time post-application, but not by study site or river. Data suggest there would be negligible exposure to non-target organisms downstream of a gB survey plot based on low niclosamide concentrations measured in the water and sediment. The depletion rate of niclosamide was also evaluated in St. Clair River sediment dosed at the field application rate. Niclosamide concentration decreased at a rate of 2.28% per hour over the 24 hours measured, equating to a half-life of 1.27 days. This indicates the length of time an organism in the sediment in a survey plot might be exposed. Underwater cameras were placed along the edge of two St. Clair River survey plots to document gB distribution on the sediment and any potential target and non-target effects. Video was inconclusive in tracking gB through the water column. Larval sea lamprey and non-target mortality were not observed. Additional video footage of one St. Clair River survey plot showed large areas of river bottom without gB.

Michigan↗

USGS2003

Comparison of spring measures of length, weight, and condition factor for predicting metamorphosis in two populations of sea lampreys ( Petromyzon marinus ) larvae

The ability to predict when sea lampreys ( Petromyzon marinus ) will metamorphose from the larval phase to the parasitic phase is essential to the operation of the sea lamprey control program. During the spring of 1994, two populations of sea lamprey larvae from two rivers were captured, measured, weighed, implanted with coded wire tags, and returned to the same sites in the streams from which they were taken. Sea lampreys were recovered in the fall, after metamorphosis would have occurred, and checked for the presence of a tag. When the spring data were compared to the fall data it was found that the minimum requirements (length ≥ 120 mm, weight ≥ 3 g, and condition factor ≥ 1.50) suggested for metamorphosis did define a pool of larvae capable of metamorphosing. However, logistic regressions that relate the probability of metamorphosis to size are necessary to predict metamorphosis in a population. The data indicated, based on cross-validation, that weight measurements alone predicted metamorphosis with greater precision than length or condition factor in both the Marengo and Amnicon rivers. Based on the Akaike Information Criterion, weight alone was a better predictor in the Amnicon River, but length and condition factor combined predicted metamorphosis better in the Marengo River. There would be no additional cost if weight alone were used instead of length. However, if length and weight were measured the gain in predictive power would not be enough to justify the additional cost.

Journal of Great Lakes Research↗