Record Details
Use of extractable lipofuscin as an age biomarker to determine age structure of ghost shrimp (Neotrypaea californiensis) populations in west coast estuaries
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Use of extractable lipofuscin as an age biomarker to determine age structure of ghost shrimp (Neotrypaea californiensis) populations in west coast estuaries |
| Names |
Cassidy, Katelyn M.
(creator) Dumbauld, Brett R (advisor) Langdon, Christopher J (advisor) |
| Date Issued | 2009-02-02T18:10:22Z (iso8601) |
| Note | Graduation date: 2009 |
| Abstract | Determining age in crustaceans is inherently imprecise because they molt periodically and do not retain hard structures throughout their lifespan. Morphological measurements, such as carapace length, are often used to estimate age because methods for direct ageing do not exist. However, variability in individual growth rate and molt frequency can result in a wide distribution of sizes in a single age class, making length a poor predictor of true age. Research examining the autofluorescent age pigment, lipofuscin, suggests that concentration of the pigment in neural tissues is directly related to actual age. Analysis of lipofuscin concentration has already proven to be a more effective method for determining true age in several species of crustaceans than traditional, length-based methods. The ghost shrimp, Neotrypaea californiensis, negatively impacts oyster aquaculture in Pacific Northwest estuaries. Current efforts to develop an integrated pest management plan for this species would benefit from better information on the age and growth of these animals. This study assessed the potential of using extractable lipofuscin as a method for determining age in N. californiensis. A growth study was conducted to validate the lipofuscin aging technique and develop a practical method of age determination for this species. Lipofuscin-based aging was used to determine age structures for three populations of N. californiensis and these were compared to age structures determined using traditional length-based methods. Age structures determined with analysis of lipofuscin concentration revealed several more age classes than assessments based on carapace length measurements in all sampled populations. Comparison of mean size-at- age among populations in Oregon and Washington estuaries showed growth rate varied spatially. Site-specific environmental factors like food availability, population density and tidal elevation may affect individual and population growth patterns. In this study, analysis of extractable lipofuscin proved to be a more accurate method of age determination than body-length measurements. The data presented here show that biochemical-based aging can now be widely used to assess age in N. californiensis, facilitating more in-depth investigations of basic biological and ecological processes for this species. |
| Genre | Thesis |
| Topic | lipofuscin |
| Identifier | http://hdl.handle.net/1957/10312 |
