Identification of biomarkers in fishes associated to cage aquaculture

Abstract

During the last decades, the increasing fish-farming activity in coastal areas have lead to a larger amount of nutrient wastes discharged into the water column and nearby sediments, which may dissipate or, alternatively, enter coastal trophic chains. The study was done in the Canary Islands (Central Eastern Atlantic), which are characterized with exposed and oligotrophic waters, at several distances from 2 different fish farms rearing Sea bass (Dicentrarchus labrax). The selected biomakers studied were fatty acid profiles, body and scales morphometries and otolith weight and otolith shape analysis. Four fish species representing different trophic guild levels were analyzed: a carnivorous/predator (Yellowmouth barracuda: Sphyraena viridensis), a herbivor (Salema: Salpa salpa), a sediment-feeder (Surmullet: Mullus surmuletus) and a plankton-feeder (Bogue: Boops boops). In this contribution, we shall discuss the main results obtained by analyzing the efficiency of those biomakers as a tool to differentiate fishes associated to aquaculture farms comparing them with wild fishes and fishes associated to seawage.