Scotland voted (overwhelmingly) to keep those powers with the EU. It did not vote for them to be passed to Westminster to be handed out like sweets to those it deems worthy.

Because issues like fisheries are best managed at the broad scale. The only people squawking here are more interested in power grabbing than they are in the responsible management of our marine environment. If Scottish nationalists actually cared about the environment and not just getting one up on the UK they would recognise that fisheries management at the UK level is the next best thing the management at the international level, and that little countries squabbling over it has historically led to terrible outcomes for the environment.