I suppose "they" know a Koi is a common carp. That may be your out - catch and kill cause you saw a yellow spot somewhere on the carcass.
Are they going to allow pike to remain (or are there pike?) ?
paraphrased from one of my fish books -- """"The northern pike (Esox lucius), known simply as a pike in Britain, Ireland, most of Canada, and most parts of the United States (once called luce when fully grown; also called jackfish or simply "northern" in the U.S. Upper Midwest and in Manitoba or Saskatchewan), is a species of carnivorous fish of the genus Esox""""
Yup, but Koi are 'manufactured' carp, and we have more than enough mongrel carp being introduced to/existing in, our waters.
My programme of training otters to only eat carp is coming along pretty well, and I would be more agreeable to immigration from eastern Europe, if they swore to only eat carp for the first 10years of coming here.
Yes there will be pike, (Esox Lucius) in the canal, they have been around for millions of years, so I think we can call them indigenous.
Angling is more than just catching fish, if it wasn't it would just be called 'catching'......... John