MEPS 353:303-306 (2008)  -  DOI: https://doi.org/10.3354/meps07352

ABSTRACT: In recent years, there has been considerable progress in the application of the cellular ageing biomarker, lipofuscin (LF), to age determination in crustacean fisheries in cases where no other reliable ageing methods exist. Two general approaches are available for LF measurement, the first involving fluorescence microscopy and image analysis of histological sections, and the second employing spectrofluorimetery of crude tissue extracts. However, for many years, controversy raged, mainly within the gerontological arena as to the validity of the second approach. Marine and fisheries ecologists may not be as aware of the problem. For example, Ju et al. (1999, Mar Ecol Prog Ser 185:171–179; 2001, Mar Ecol Prog Ser 224:197–205 and elsewhere) report application of the LF ageing method to demographic analysis of the economically important blue crab Callinectes sapidus using biochemical quantification procedures. This is an important issue because useful conclusions about valuable bioresources cannot be drawn where analysis techniques are flawed. In the present paper I discuss the main concerns regarding past attempts to quantify LF biochemically for age determination of crabs: (1) extracted fluorescence remains unidentified; (2) no correlation between extracted fluorescence and in situ LF concentration has ever been demonstrated; (3) there is no evidence that normalization to cellular protein produces a reliable LF assay; (4) dependence of fluorescence intensity on extracted tissue mass can be misleading; and (5) high throughput biochemical measurement does not compensate for absence of specificity. Despite the inherent challenges associated with devising a reliable biochemical quantification method for neurolipofuscin, there remains little doubt that such a development will be a significant advance both in marine- and fisheries ecology and in the wider arena of gerontology.

KEY WORDS: Age determination · Biochemical extraction · Crabs · Error · Histology · Lipofuscin quantification · Protein normalization · Specificity