Data obtained from purse-seine observers carry out by the Instituto Español de Oceanografía from the National Database Plan between 2003 and 2006

We present data about vessel activity obtained by observers on board purse-seiners operating in the Indian Ocean between 2003 and 2006. Observation days totalled 601 in over 17 campaigns. We outline catches and discards per species and type of association. In this period, 477 sets were performed, involving catches of 17184 t of tuna, of which 490 t were discarded (corresponding to 2.9% of the total catch, with 0.5% in sets over free schools and 1.9% of sets over objects). We compare data obtained from the fishery in the same period. Likewise, we present information about purse-seiner activity in relation to floating objects. Finally, we include bycatch data, such as the presence index per type of association, size distribution and turtle catch data.