I think I read that some species of fish were becoming smaller, as this made it so they evaded nets.

just possibly, selective breeding could produce fish that lay eggs when they are little fish, yet continue to grow afterwards to become large fish. The large fish would then be netted, after their reproductive period. This new variety of fish would then be plentiful.

I think salmon might be selectively bred to do this, as they already have strange reproductive behaviors. Also there are (partially) parthenogenic fish which might be bred to clone themselves early.
-- beanangel, Oct 13 2016

One species of always-growing fish http://www.cnn.com/...ed-goldfish-giants/
As mentioned in an annotation. [Vernon, Oct 14 2016]

There are already fish that keep growing until they die, no matter how young they are when they breed. I'll post a link.
-- Vernon, Oct 14 2016



random, halfbakery