This paper considers the problem of multiple-species fishery management when targeting individual species is costly and at-sea discards of fish by fishermen are unobserved by the regulator. A dynamic model is developed to balance the ecological interdependencies among multiple fish species, and the technological interdependence which captures costly targeting. Stock conditions, ecosystem interaction, technological specification, and relative prices under which at sea discards are acute are identified. Three regulatory regimes, species-specific harvest quotas, landing taxes, and revenue quotas, are contrasted against a hypothetical sole owner problem. An optimal plan under any of these regimes precludes discarding. For both very low and very high degrees of technological interdependence, first best welfare is close to that achieved through regulation. In general, landing taxes welfare dominate species-specific quota regulation; a revenue quota fares the worst.