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

In crustaceans. the lack of reliable methods often prevents the determinati on of individual age. The quantification of the autofluorescent age pigment , lipofuscin. has revealed promising results in boreal and tropical species . We studied the presence of morphological lipofuscin and its possible appl ication as an age marker in five Arctic and five Antarctic species. compris ing decapods, amphipods and a euphausiid. Lipofuscin granules were located in the brain, using confocal fluorescence microscopy, and quantified from d igital images. The pigment was found in 94 of 100 individuals and in all 10 species, and granules occurred in easily detectable amounts in 5 species. Two scavenging amphipod species, the Antarctic Waldeckia obesa and the Arct ic Eurythenes gryllus, revealed the most conspicuous and numerous granules. There was a broad, though weak, correlation of lipofuscin concentration wi th individual body size within a species, but not with absolute body size o f one species compared to another. In larvae of the decapod Chorismus antar cticus, lipofuscin accumulation was quantified over the 1st 4 months after larval release. Morphological lipofuscin is a potential index of age in tho se investigated species with a sufficient accumulation rate of the pigment.