tender for the purchase of services for the provision of national bluefin tuna fishery control observer services, who will be placed on fishing vessels actively fishing bluefin tuna and towing vessels transporting bluefin tuna from the fishing vessels to the bluefin tuna fattening farms, for the year 2023. the offer concerns the purchase of services for the provision of national fishery control observer services on four (4) fishing vessels actively fishing bft and on two (2) towing vessels.