BIOMETRIC-ANALYSIS OF SOME CYPRINID BONES OF PREY FISHES TO ESTIMATE THE ORIGINAL LENGTHS AND WEIGHTS

The relationships between the lengths of dentaries, premaxillae. maxillae and pharyngeal bones lengths and standard length and total wet weight were examined in 4 prey fish species (Barbus sclateri, Chondrostoma polylepis, Leuciscus cephalus pyraenaicus and Cyprinus carpio). These bones were found and easily identified in most (68 %) of 349 otter spraints collected from the Guadalete river (Cadiz, South Spain). Relationships between bone length and fish length were linear, and between bone length and fish botal wet weight multiplicative (Y = a . x(b)) in all cases except in the barbel, which were nonlinear, fitting them to a function with the form Y = = a . b(x.x) ; coefficients of determinism (r2) ranged from 83.35 % to 98.62 %. Finally, we discuss different methods and fish bones employed to estimate fish predator diets, in relation to the methodology and bones proposed in this work.