There is another reason that I haven't seen mentioned yet for clipping some of the Stilly fish. There is really no other way (that I am aware) to evaluate the impacts of mark selective fisheries (MSF) on specific populations without doing this double index tagging (DIT). In short, some fish are tagged and marked (susceptible to MSF fisheries) and others are tagged and not marked (not susceptible to MSF fisheries). Comparing the harvest (exploitation) rates on the two groups lets you estimate the impact of the fishery. Pretty important to know if you want to keep having these types of fisheries. As discussed above, there can also be a downside, particularly when REALLY important fish are used for DIT rather than using just a hatchery population (thought to represent some real natural population) for the DIT as is done for some PSC indicator stocks (if that is what they are still called).