Animals, Macaronesia, Rivers, Madeira, Brazil, Spectrophotometry, Atomic, Muscles - chemistry, Spectrometry, Mass, Electrospray Ionization, Food Contamination - analysis, Catfishes - metabolism, Electrophoresis, Gel, Two-Dimensional, Fish Proteins - chemistry, Fish Proteins - isolation \& purification, Mercury - isolation \& purification, Proteome - chemistr...