Use of extractable lipofuscin to estimate age ­structure of ghost shrimp populations in west coast estuaries of the USA

Abstract

Determining age in crustaceans is inherently imprecise because they molt periodically and do not retain hard structures throughout their lifespan. Morphological measurements are often used to estimate age, but variability in individual growth rate and molt frequency can result in a wide distribution of sizes in a single age class, making size a poor predictor of true age. Concentration of the autofluorescent age pigment, lipofuscin, has been shown to be directly related to actual age in many crustaceans. The present study assessed the potential of using extractable lipofuscin as a method for determining age in the ghost shrimp Neotrypaea californiensis. Following validation of the technique, lipofuscin-based aging was used to determine age structures for 3 populations of N. californiensis, and these were compared to age structures determined using traditional lengthbased methods. Analysis of lipofuscin revealed up to 13 age classes where the size-based analysis showed only 7. Comparison of mean size-at-age among populations in Oregon and Washington estuaries demonstrated that growth rate varied spatially, probably responding to site-specific environmental factors like food availability and population density. N. californiensis negatively impact oyster aquaculture in Pacific Northwest estuaries. Analysis of extractable lipofuscin proved to be a more accurate method of age determination than body-length measurements and should facilitate more indepth investigations of basic biological and ecological processes, which will benefit current efforts to develop an integrated pest management plan for N. californiensis.

Alternative intrapopulation life‐history strategies and their trade‐offs in an African annual fish

“…Lipofuscin is autofluorescent marker that is used for identifying age-related accumulation of oxidative damage, and it typically accurately reflects histological ageing across various organs (Ding et al, 2010;Bosley & Dumbauld, 2011;Yu & Li, 2012;Terzibasi-Tozzini et al, 2013). Despite differing durations in lifespan, lipofuscin was deposited in the liver at a comparable level between treatment groups, implicating a similar rate of intrinsic ageing in fast and slow fish, measured at the histological level.…”

Problems associated with a lipofuscin extraction method used to age blue crabs Callinectes sapidus cultured in Florida, USA

“…The extraction technique has been applied to a number of marine species, including ghost shrimp Neotrypaea californi ensis (Bosley & Dumbauld 2011), euphausiids Euphausia pacifica and E. superba (Harvey et al 2010), blue crab Callinectes sapidus (Ju et al 1999, Dickinson et al 2006, Puckett et al 2008), a teleost, Oreochromis mossambicus (Hill & Womersley 1991), western rock lobster Panulirus cygnus, scampi Metanephrops andamanicus (Crossland et al 1988), spider crab Hyas araneus (Hirche & Anger 1987), and the terrestrial fleshfly Sarcophaga bullata (Ettershank et al 1983), all of which showed an accumulation of lipofuscin with increasing age in both extraction and histological analyses. In contrast, we found that blue crabs living in tanks for 11 mo or in a pond for 18 mo did not show a linear increase in lipofuscin over time.…”

Ascidia subterranea sp. nov. (Phlebobranchia: Ascidiidae), a new tunicate belonging to the A. sydneiensis Stimpson, 1855 group, found as burrow associate of Axiopsis serratifrons A. Milne-Edwards, 1873 (Decapoda: Axiidae) on Derawan Island, Indonesia

“…A shrimp species closely related to Axiopsis serratifrons, the axiid Calocaris macandreae Bell, 1853, was assumed to live up to 10 years by Buchanan (1963). According to Bosley & Dumbauld (2011), the more distantly related axiid Neotrypaea californiensis Dana, 1854, might live to ten years or more. Axiopsis serratifrons may be similarly long-lived, and due to the fact that the species lives in pairs, it probably inhabits the same burrow over its entire post larval life span.…”