The idea of shifting baselines is all about perception from generation to generation. So the baseline of what is normal for abundance in one generation becomes smaller the next generation in what they perceive to be baseline for abundance. It progressively continues until expectations of abundance is very low. This is what may have been part of the demise of Northern Atlantic Cod because people continued to fish even though the abundance continued to decrease until it hit a critical point. The one way we could prevent this is by making sure that management decisions are made based on the abundance compared to the years before. This will ensure that the baseline stays relatively the same through generations.
I agree that in order to maintain the population at a sustainable level, both for the human economy and the ecosystems capacity, our management must always set regulations in response to returning fish populations. If we don’t, then we run the risk of overfishing the populations.