UVM Theses and Dissertations
Format:
Print
Author:
Howe, Eric Austen
Title:
Dept./Program:
Wildlife and Fisheries Biology Program
Year:
2004
Degree:
M.S.
Abstract:
Sea lamprey (Petromyzon marinus) is a nuisance species in the Great Lakes and Lake Champlain that has had devastating impacts on native fish and the development of sport fisheries. United States Fish and Wildlife Service personnel use Quantitative Assessment Surveys (QAS) to assess larval densities of sea lamprey in Lake Champlain tributaries. The results of these evaluations are used to target tributaries for use of larval lampricides. The purpose of this study is to evaluate the accuracy of the QAS using independent population estimators. Three tributaries were targeted for this evaluation in fall 2001 and 2002. In fall 2001, mark-recapture techniques using electroshocking and fyke netting were implemented in Lewis Creek, Malletts Creek and the Poultney River in VT and Morpion Stream in Quebec. In fall 2002, a modified mark-recapture technique was implemented in Putnam Creek, NY using collection of transformers killed in a lampricide treatment for the recapture phase. A Lincoln-Petersen estimator was used to estimate the population of transformers for the mark-recapture studies and was compared to the QAS estimates for the same population.
A removal-depletion technique was used in the Little Ausable River, NY and Malletts Creek, VT. Plots were blocked off in each tributary, and a series of passes were made using an electroshocking unit, removing lamprey with each pass. Densities within each plot were calculated and extrapolated to the rest of the tributary. A whole-stream mark-recapture estimate was used in Malletts Creek as a second independent estimator. Comparisons of the four estimators (QAS, removal, plot mark-recapture, and whole stream mark-recapture) indicate no differences among the population estimates. Of the four techniques, the whole-stream mark-recapture yielded the tightest confidence intervals, while the QAS and removal methods had the broadest confidence intervals. The mark-recapture and removal methods generate population estimates within acceptable confidence intervals of the QAS estimates, indicating that the QAS technique may be an appropriate tool for evaluation of larval sea lamprey in tributaries.
A removal-depletion technique was used in the Little Ausable River, NY and Malletts Creek, VT. Plots were blocked off in each tributary, and a series of passes were made using an electroshocking unit, removing lamprey with each pass. Densities within each plot were calculated and extrapolated to the rest of the tributary. A whole-stream mark-recapture estimate was used in Malletts Creek as a second independent estimator. Comparisons of the four estimators (QAS, removal, plot mark-recapture, and whole stream mark-recapture) indicate no differences among the population estimates. Of the four techniques, the whole-stream mark-recapture yielded the tightest confidence intervals, while the QAS and removal methods had the broadest confidence intervals. The mark-recapture and removal methods generate population estimates within acceptable confidence intervals of the QAS estimates, indicating that the QAS technique may be an appropriate tool for evaluation of larval sea lamprey in tributaries.