Looks like American blight, a common problem with gooseberries. The berries are still edible if you can be bothered to scrape it off. . Prune the bushes to an open shape in Feb for good air circulation and tip prune now as the fungus will overwinter in the ends of the branches.. There is nothing you can do to cure it at this stage. If the problem keeps recurring in future years replace the bushes with a blight resistant variety - there's a good selection nowadays - Invicta and Greefnfinch are two.