No interactions present.
In a species like Cormorant where there is intergradation between the subspecies, I don't really think it is worth trying to identify individuals subspecifically. P. carbo covers them both and seems to be the safer option, about which we truly can be 'sure'.
My Flickr photos...
There is limited evidence of intergradation between the subspecies (there is even a suggestion that they may be cryptic species due to niche seperation). The criteria I have just revisited indicate that below a 65 degree angle is carbo and above 73 degrees is sinensis with a 98% degree of accuracy. Sinensis are displacing carbo inland as they advance NW. There is similar divergence between the races as between hooded and carrion crow genetically. I concede that the other bird could be sinensis but the gular angle must be measured. This bird is certainly carbo.
reference: Garner, M. (2008) Frontiers in Birding, Birdguides, Sparkford
If there is some evidence of hybridisation between the two, which apparently there is in England, that might be another reason to leave subspecies out of it.
Are sinensis really displacing carbo inland? I have heard different thoughts on that (though I can't find the reference at the moment).
I agree that this is probably subspecies carbo, but I still maintain it is safer to stick to P. carbo alone. There was a period a while ago when every cormorant with white on its neck was claimed as sinensis, but that has now been disproved as a feature...
Lat/Lng: 55.1787, -1.6165
OS grid ref: NZ245872