This paper considers the problem of multi-species fisheries management when targeting individual species is costly and at-sea discards of fish by fishermen are unobserved by the regulator. Stock conditions, ecosystem interaction, technological specification, and relative prices under which at...

Flaaten’s (1991) study on competing species conjectures that a higher price (harvesting costs) of one species yields a lower (greater) own stock-size and a greater (lower) stock-size of the competing species. I show both conjectures are wrong.