Estimating age and growth in long‐lived temperate freshwater crayfish using lipofuscin

Abstract

1. In ecological studies on freshwater crayfish, determination of basic population parameters is often complicated by the lack of a suitable age estimation method. 2. Previously, lipofuscin age pigment in the olfactory lobe cell masses (OLCM) of short‐lived tropical crayfish has been used for accurate age determination. Here we present the first test of this method on a longer‐lived, temperate species, the signal crayfish, Pacifastacus leniusculus. 3. Confocal fluorescence microscopy and image analysis of histological sections were used to quantify OLCM lipofuscin in a reference sample of Swedish P. leniusculus from several known year‐classes, reared under naturally variable temperature conditions. Lipofuscin concentration was linearly associated with age (r2 = 92.4%) and produced much more accurate age estimates than conventional body size‐based procedures. 4. A model derived from the crayfish of known‐age was used to estimate the ages of wild P. leniusculus from an English stream. The relationship between lipofuscin‐estimated age and carapace length suggested relatively slow growth in this wild population, consistent with a high population density and severe competition. The analysis also extended the known longevity of P. leniusculus to approximately 16 years. 5. The lipofuscin method for determining age and growth may be widely applicable to freshwater crayfish, with probable further potential both within and outside the Crustacea.

Molt and gastroliths inAustropotamobius pallipes(Lereboullet, 1858)

“…By using external tags or similar markings in molting periods of less frequency, it is possible to avoid the use of invasive techniques for 'structuring' (i.e. ageing) crayfish populations, such as the analysis of lipofuscin granules (Belchier et al, 1998), and the recapture method of Abrahamsson (1965) and its modifications (Burič et al, 2008;Scalici et al, 2010a), the latter representing the beginning of possible infections that can compromise the health of marked individuals. Invasive methods concern heat-marking on the coxae or carapace by soldering guns and the use of (1) passive integrated transponder tags (Wiles and Guan, 1993;Bubb et al, 2002), or (2) visible elastomer tags (Partanen and Penttinen, 1995;Jerry et al, 2001).…”

Evidence of lipofuscin accumulation in the deep-water red shrimp Aristaeomorpha foliacea (Risso, 1827)

“…Despite the heterogeneous composition and genesis of lipofuscin, its relationship with aging has been demonstrated in many groups of crustaceans such as krill (NICOL et al, 1991), amphipods (BLUHM et al, 2001), clawed (O'DONOVAN & TULLY, 1996SHEEHY et al, 1996;WAHLE et al, 1996;SHEEHY et al, 1999;CASTRO et al, 2002;) and spiny lobsters (SHEEHY et al, 1998), crayfish (SHEEHY, 1990a;SHEEHY et al, 1994;BELCHIER et al, 1998) and shrimps, both caught in the wild or raised in aquaculture (SHEEHY et al, 1995;VILA et al, 2000;MEDINA et al, 2000;SOBRINO et al, 2001;PEIXOTO et al, 2002;VILA GORDILLO, 2005). These studies, based also on animals kept in controlled conditions, allowed the improvement of extraction and methods of analysis, as well as the confirmation that, regardless the sex, lipo- Medit.…”

Occurrence of the autofluorescent pigment, lipofuscin, in polar crustaceans and its potential as an age marker

“…Those specimens without obvious pigment granules do not necessarily lack the pigment, but granules may not have been detectable with the applied methodology. Although we tried to include specimens close to the known maximum size of the species, age-pigment concentrations ranged an order of magnitude lower than measured in species from lower latitudes Belchier et al 1998).…”

“…The author concluded that the histologically based quantitative method with concurrent visual microscopic veri®cation of in situ morphological lipofuscin's¯uorescence and histochemical attributes is the only reliable method for quanti®cation. Several recent studies have been attempted to assess the applicability of morphological lipofuscin as an age marker (O'Donovan and Tully 1996; Belchier et al 1998;Sheehy et al 1998). Besides E. superba (Sheehy 1990a), no other species from high latitudes has been studied until now.…”