I litter pick on the beach every day and also volunteer for a marine conservation group and plastic free charity.
Every single day I find fishing detritus. Cat food pouches (obviously used as bait), lines, hooks, weights, bait bags and nets. Also all the other rubbish they just leave after a day out - vapes, cider cans and bottles, tea bags (often contain plastic), sandwich packets.
The deeply irritating thing for me is that these are man (they're mostly men) who obviously enjoy a day in the great outdoors and nature and yet are happy to leave it in a worse state after their visit.
I'm so glad your poor dog is doing so well and wish that nobody had to suffer this in future.