Ra. Wahle et al., LIPOFUSCIN AS AN INDICATOR OF AGE IN CRUSTACEANS - ANALYSIS OF THE PIGMENT IN THE AMERICAN LOBSTER HOMARUS-AMERICANUS, Marine ecology. Progress series, 138(1-3), 1996, pp. 117-123
Lipofuscin content was determined in the brains of 41 American lobster
s Homarus americanus (Milne-Edwards) aged 4, 13 and 27 mo reared indiv
idually at 19 to 20 degrees C. Lipofuscin was quantified by fluorescen
ce microscopy and image analysis. Lipofuscin granules occurred in each
age group and in the oldest group appeared as large aggregations coll
ectively averaging 2.1% of the area of histological sections of the ol
factory lobe cell mass. Carapace length-corrected lipofuscin area % ga
ve the highest correlation with age (r = 0.99, p < 0.0001) and a non-l
inear best fit regression (y = 0.00264 x Age(2.03)). The size and numb
er of lipofuscin granules and carapace length were also significantly
related to age. Lipofuscin concentration was not significantly correla
ted with carapace length within any of the 3 age classes (4 mo: r = -0
.078, 13 mo: r = -0.20, 27 mo: r = -0.351). These results suggest the
possibility that the lipofuscin technique can differentiate cohorts in
natural populations. However, environmental temperature and the possi
bility of other factors affecting metabolic rate may need to be taken
into account when attempting to apply the laboratory model to wild pop
ulations.