Geology topics

John W. Weisser

Publications and source records attributed to John W. Weisser.

3 recordsLinked to original sources

USGS2003

Techniques and methods for estimating abundance of larval and metamorphosed sea lampreys in Great Lakes tributaries, 1995 to 2001

Before 1995, Great Lakes streams were selected for lampricide treatment based primarily on qualitative measures of the relative abundance of larval sea lampreys, Petromyzon marinus. New integrated pest management approaches required standardized quantitative measures of sea lamprey. This paper evaluates historical larval assessment techniques and data and describes how new standardized methods for estimating abundance of larval and metamorphosed sea lampreys were developed and implemented. These new methods have been used to estimate larval and metamorphosed sea lamprey abundance in about 100 Great Lakes streams annually and to rank them for lampricide treatment since 1995. Implementation of these methods has provided a quantitative means of selecting streams for treatment based on treatment cost and estimated production of metamorphosed sea lampreys, provided managers with a tool to estimate potential recruitment of sea lampreys to the Great Lakes and the ability to measure the potential consequences of not treating streams, resulting in a more justifiable allocation of resources. The empirical data produced can also be used to simulate the impacts of various control scenarios.

Journal of Great Lakes Research↗

USGS2003

Response of larval sea lampreys ( Petromyzon marinus ) to pulsed DC electrical stimuli in laboratory experiments

Four electrical factors that are used in pulsed DC electrofishing for larval sea lampreys ( Petromyzon marinus ) were evaluated in two laboratory studies to determine the optimal values to induce larval emergence over a range of water temperatures and conductivities. Burrowed larvae were exposed to combinations of pulsed DC electrical factors including five pulse frequencies, three pulse patterns, and two levels of duty cycle over a range of seven voltage gradients in two separate studies conducted at water temperatures of 10, 15, and 20°C and water conductivities of 25, 200, and 900 μS/cm. A four-way analysis of variance was used to determine significant (α = 0.05) influences of each electrical factor on larval emergence. Multiple comparison tests with Bonferroni adjustments were used to determine which values of each factor resulted in significantly higher emergence at each temperature and conductivity. Voltage gradient and pulse frequency significantly affected emergence according to the ANOVA model at each temperature and conductivity tested. Duty cycle and pulse pattern generally did not significantly influence the model. Findings suggest that a setting of 2.0 V/cm, 3 pulses/sec, 10% duty, and 2:2 pulse pattern seems the most promising in waters of medium conductivity and across a variety of temperatures. This information provides a basis for understanding larval response to pulsed DC electrofishing gear factors and identifies electrofisher settings that show promise to increase the efficiency of the gear during assessments for burrowed sea lamprey larvae.

Journal of Great Lakes Research↗

USGS2003

Effects of repeated TFM applications on riffle macroinvertebrate communities in four Great Lakes tributaries

As part of the sea lamprey control program in the Great Lakes, a suite of about 150 sea lamprey producing streams have been regularly treated with the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) every 3 to 5 years since 1958. State, provincial, and tribal agencies in the basin supported the use of TFM and urged that the risk to nontarget organisms be minimized. To determine the response of riffle macroinvertebrate communities to repeated TFM treatments over several years, paired samples were taken at control and treatment sites during 1986 to 1995 on four Great Lakes tributaries: the Bois Brule, West Branch Whitefish, Boardman, and Sturgeon (tributary to Cheboygan River system) rivers. Macroinvertebrates were collected in spring and fall by a standard traveling kick method. The communities were described with several metrics, and general linear models were used to test for different patterns of response in the paired control and treatment sites. Relative abundance of the class Oligochaeta, relative abundance of the genus Ephemerella , the Bray-Curtis similarity index (at the taxonomic level of order), EPT genus richness (the number of genera in the orders Ephemeroptera, Plecoptera, and Trichoptera), and total genus richness all increased more at the treatment sites than at the control sites after TFM application. The greater increase in abundance, similarity, and richness at the treatment sites was an indication of recovery in the treatment sites, where a short-term response to TFM was followed by a several-year rebound. TFM treatments in this study during the 1980s and 1990s had no long-lasting effects on riffle macroinvertebrate communities.

Journal of Great Lakes Research↗