> While real UK manufacture successes (cars, aircraft, satellites, generators, all sorts of high-tech stuff) get completely ignored

Here is my take on this:

For those things, you probably need a lot of technical training and/or advanced degrees.

For fishing you just need to be more or less healthy and be able to follow instructions.

Most people are more or less healthy and are able to follow instructions. A small subset of those has advanced technical training and/or advanced degrees.

Therefore, fishing becomes important because a lot more people can do it, and those people vote.