From M. R. J. Sheehy
Your report implies that working out the age of crustaceans from their neural
lipofuscins—fatty hydrocarbon pigments—is a novel development by
Se-Jong Ju at the University of Maryland’s Chesapeake Biological Laboratory
(5 February, p 10).
The ability to age crustaceans is extremely important for fishery management.
This method of determining age was suggested by G. Ettershank as long ago as
1983, and in 1989 I showed that the approach worked for crustaceans, including
crabs.
However, the method may not be very accurate. Other studies have shown that
the unpurified fluorescent materials extracted from crustacean neural tissue by
Ju’s method are almost certainly not derived from lipofuscin granules in the
tissues, as they bear no quantitative relationship to them, or to age, only to
tissue sample mass and body mass. Where mass is broadly related to age this can
easily lead to misinterpretation of the results. Ju provides no convincing
additional evidence to the contrary.
mrjs2@leicester.ac.uk
