Knowing the age structure of a population is fundamental to understanding it ecological role, and for commercial species, its effective management. In many species, age determinations are made by the examination of hard parts that show incremental growth over time including otoliths, scales, molluscan shells and teeth. Crustaceans, however, replace their exoskeleton each time they molt, losing any trace of previous age and our group has developed and applied biochemical approaches to provide age estimates. Originally developed for the blue crab, our approach utilizes the cellular accumulation of cellular oxidation products (termed lipofuscins), which can be quantified and used as a proxy for age. Slight modifications have allowed us to expand our approach to include other crustaceans, particularly euphausiids (krill). Areas of study have included the Southern and North East Pacific Oceans, and currently focus on the Bering Sea.
Information on age structure is often combined with detailed analysis of lipids, which serve structural, reproductive and energetic roles. Our group has focused on lipid analysis and structural characterization for over twenty year. For crustaceans, the emphasis is on the use of lipids as taxonomic markers and as tracers of trophic relationships. Most recently, we have focused on euphausiids which live in extreme environments (e.g. Antarctica and polar oceans) and where lipids can help understand food web dynamics in the changing marine ecosystems such as the Bering Sea.
Related papers and links
Harvey, H.R., Pleuthner, R.L., Lessard, E.J., Bernhardt, M.J., and Shaw, C.T. 2012. Physical and biochemical properties of the Euphausiids Thysanoessa inermis, Thysanoessa raschii, and Thysanoessa longipes in the eastern Bering Sea. Deep Sea Research II
Pleuthner, R., Lessard, E., Schatz, M., Shaw, T., and Harvey, H. R., 2012. Dietary history and lipid retention in Bering Sea Euphausiids. Ocean Sciences Meeting, 20-24 February, Salt Lake City, Utah. Poster Presentation
Harvey, H.R., Ju, Se-J., Son, S-K., Feinberg, L.R., Shaw, C.T., Peterson, W.T., 2010. The biochemical estimation of age in Euphausiids: Laboratory calibration and field comparisons.Deep-Sea Research II 57: 663–671.
Pleuthner, R., Lessard, E., Schatz, M., Shaw, T., and Harvey, H. R., 2010. Euphausiid responses to changing food resources: Lipids as molecular tracers of diet history in the Bering Sea. Ocean Sciences Meeting, 21-26 February, Portland, Oregon. Poster Presentation
Ju, S.-J., Kang, H.-K., Kim, W.S., and Harvey, H.R., 2009. Comparative lipid dynamics of euphausiids from the Antarctic and Northeast Pacific Oceans. Marine Biology 156:1459–1473.
Harvey, H.R., Secor, D.H., and Ju, S.-J., 2008. The use of extractable lipofuscin for age determination of crustaceans: Reply to Sheehy (2008). Marine Ecology Progress Series353:307–311.
Harvey, H.R., Dyda, R.Y., and Kirchman, D.L., 2006. Impact of DOM composition on bacterial lipids and community structure in estuaries. Aquatic Microbial Ecology 42:105-117.
Poster presentations from the GLOBEC Symposium: Climate variability and Sub-Arctic marine ecosystems, 16-20 May 2005, Victoria, B.C., Canada. Ju, S.-J. and Harvey, H.R. Lipid ecology of Euphausiids in the north Eastern Pacific and Polar Oceans; and Harvey, H.R., et al. Biochemical determination of population age structure in Euphausiids.
Ju, S.-J. and Harvey, H.R., 2004. Lipids as markers of nutritional condition and diet in the Antarctic krill Euphausia superba and Euphausia crystallorophias during austral winter.Deep-Sea Research II 51:2199-2214.
Ju, S.-J., Scolardi, K., Daly, K.L., and Harvey, H.R., 2004. Understanding the trophic role of the Antarctic ctenophore, Callianira antarctica, using lipid biomarkers. Polar Biology 27:782-792.