On the otter question - three really important points
1. this is not like Wolves or Beavers - the Otter population crash was only 65 - 45 years ago
2. re-introductions played a tiny part in the re-establishment (see Broughton's note)
3. they are now the Apex predator in the ecosystem and compete with us for resources (ie. fish) - but all predator populations are self-regulating over time (except humans that is).
so - it's really not a good look to be calling for culls of a native species success story, much as I regret any loss of fish stocks.
personally - I'm much more worried about the impact of increased population and climate change on fish stocks than I am about otters or cormorants.