Abstract

Stable isotope analysis (SIA) is used to determine animal diets and construct food webs. Tissue sampling methodology for SIA is usually lethal to the study organism. As various species become endangered worldwide, it is important to develop non-lethal methods of sampling tissues for SIA. In crustaceans, animals are usually killed and abdominal tissue is used for SIA. We sampled tissues from other body parts (walking legs, antennae) of the Caribbean spiny lobster (Panulirus argus) that can be removed without killing the animal to determine if they would produce SI signatures similar to abdominal tissue. Lobsters were collected from seagrass meadows in the vicinity of Caye Caulker, Belize during July and August of 2006. Tissue samples were taken from 10 adult lobsters, 5 males and 5 females. Leg and abdominal ?13C values were not significantly different; antennal ?13C signatures were significantly different from those of abdominal tissue. Regression analysis demonstrated that isotopic carbon ratios from leg tissue were better predictors of abdominal carbon ratios (r2=0.918). Leg tissues had significantly higher ?15N signatures than abdominal tissue and antennal ?15N values were significantly lower than abdominal values. We conducted a regression analysis to determine if either leg or antennal tissue SI values would be a good predictor of abdominal ?15N values. The r2 for the relationship between abdominal tissue and antennal tissue (r2=0.677) was higher than that for leg and abdominal tissue (r2=0.476). Despite the poorer relationship between leg and abdominal N signatures we feel that walking legs are the preferred tissue to remove since the loss of one walking leg probably has less of an effect on lobsters than the loss of an antenna. Our results suggest that tissue removed from other body parts of crustaceans can be used to assess diet and determine trophic level assignment

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