Project Number: UR089
Project Title: Evaluating statolith metrics as a method to age larval sea lamprey
Faculty Sponsor: Heather Dawson
Proposed Starting Date: 05/09/2011
Proposed Ending Date: 08/22/2011
Student in mind: Yes
Number of hours to work per week: 1-6 hours
Project Description: The sea lamprey (Petromyzon marinus) control program is a critical component in the Laurentian Great Lakes because it significantly reduces the mortality of Great Lakes fish caused by the feeding of parasitic sea lamprey, thereby facilitating the rehabilitation of fish stocks important to the integrity of the Great Lakes and tourism in Great Lakes states such as Michigan. Since the late 1950s, chemical methods have been the primary means of sea lamprey control, and involve the application of a lampricide to kill larvae (ammocoetes) in Great Lakes tributaries before they undergo metamorphosis and become parasites. Because the cost of lampricide prohibits treating all streams that will produce parasitic sea lampreys each year, information on ammocoete abundance, growth, and survival in streams is used to rank streams for lampricide treatment. However, analyses that require age composition data such as ammocoete growth and survival have been discouraged by the unreliability of age-assessment methods for ammocoetes. Determining age based on visual assessments of length-frequency distributions is subjective and uncertain, and determining age based on counts of annuli on statoliths has been found to be imprecise and inaccurate. However, statoliths are the analogous structure in lampreys to otoliths in teleost fishes, and otolith size is more correlated with fish age than is fish length. We propose to use a known-age population of ammocoetes to evaluate whether statolith size is correlated with ammocoete age, and evaluate the accuracy of an objective, statistical method for ammocoete age assessment that combines length-frequency and partial age composition data.
1) Determine whether statolith size is correlated with ammocoete age. 2) Evaluate a statistical method for ammocoete age assessment that combines length-frequency data with partial age composition data (using statolith size to infer age). 3) Provide information to the Great Lakes Fishery Commission that will aid in the management of this invasive species (the Great Lakes Fishery Commission is a binational commission located in Ann Arbor, MI which influences public policy on the environment in U.S. states and Canadian provinces that border the Great Lakes).
We will use prepared statoliths collected from known-age ammocoete populations (age 1 to age 4) established in a previous study by Dawson et al. 2009. We will use a morphometric system, which includes a digital microscope camera, associated software, and computer to measure the length, width, and height of statoliths from prepared statoliths from these known-age populations. Because statoliths have already been extracted from larval sea lampreys and mounted on slides, we will not directly be working with vertebrate animals in this study. We have over 500 statoliths to analyze from these known-age populations. We will compare all three measurements to the true age of the statolith to assess how tightly correlated each measurement is to the true age.
Student Tasks & Responsibilities: 1. Work with a microscopic morphometric system to take measurements of fish statoliths. 2. Use Microsoft Office products to evaluate whether fish age can be inferred from statolith size. 3. Communicate with a graduate student and the faculty advisor on a regular basis to discuss progress of the project.
Minimum Student Qualifications: 1. Attention to detail. 2. Familiarity with the use of Microsoft Office products. 3. Good comunication skills. 4. Interest in fisheries and wildlife research.