indeed, its an interesting topic and you dont find so much in the net about it. did a little google research yesterday and apart from Eskimo hunting which is a thing for itself pics are rare.

this here is from Denmark in the the 1950s

double guns? maybe
found it on a danish blog about marine mammal's http://www.hvaler.dk/nyheder2008.htm

this pic is remarkable because they have clearly muzzle loader but its named "seal hunting on ice in 1904"

very late for seeing a muzzle loader in action

the story of the seal after the stop of hunting is also very remarkable

again the fact's:
around 1900 the seal was hunted very hard in North and Baltic sea by fisherman because he was a rival for fish. the common seal feed 4-8 kg fish a day, let's say 6 kg and if we make a little calculation for the 8400 seals(ok, some are pups) between Hamburg and Emden on the dutch border they feed 50,4 ton's fish a day and beause they have hunger every da in the year they need 18396 ton's fish in 2012.

the hunting on seal's stop in 1962 Netherland, 1973 Germany, 1977 Denmark

and now it became trilling:
in 1988 a 18000 of 27000 seal's dying in North and Baltic sea on the PD virus which is some kind of Canine distemper.
you know it was a unique catastrophe but - miraculous - in 2002 there are enough seals again for the PD virus 22000 seal's could dying. Btw, dying on the PD virus seems not to be fun for the seal's.
it seems the origin of this was Anholt island in Denmark every time which is located strategic between North and Baltic sea.

In 2007 again dead seals were found on Anholt but the epidemic dont start.

http://www.welt.de/wissenschaft/article974034/Staupe-Epidemie-bei-Seehunden-ausgebrochen.html

the so called conservation organisations claim that the reason for the epidemic is marine pollution and that's maybe part of the problem but is this the core? Because the PD virus was found with Mink's in fur farmings on Anholt in 1988 they claim that fur farming was the core ( very clever) but other scientist say the virus was coming from the seal's into the farm's.
Now such organisation's complain that nobody search for the reason's but why dont they use their donation's for a study?
I understand that tax money is much better for such thing's!
One fact is that saddle back seal's come to Anholt in very hard winter's from the north and they have the PD virus but being immune.

Another idea: I read once that the Rabies disease was very rare in area's were the red fox was hunted hard. 100 year's ago three red fox winter fur's were worth a drilling and you can imagine how they hunt the fox then. Rabies is eradicated now and fur's are worth nothing so mother nature have another epidemic, now canine distemper, if the the fox population become the high.

Could it be that the seal population must reach a certain point before the epidemic breaks out?
Could it be that holding the population under this certain point by hunting managment would be a help. I hear that seal hunting is discussed in Denmark now maybe one of our danish member's know's more.

Sadly, marine pollution seems not to be a problem for the Great Cormorant.
once hard hunted like the seal because he is a rival for fish this bird is now untouchable here. conservation group's claim he need's complete protection.because he is close to extinction.

I may this pics on Usedom Island in the baltic see in july

the flock of commorant's was to large to get it on one pic. They roam the coast on 300-400 meter
and local fisherman told me this are sometime's 5000-6000 bird's.
You can imagine its the darling there
what do they feet? To my understanding you find only school's of juvenile fish so close to the beach
where they found some kind of protection not having into the open sea. Until the commorant is coming.
better dont shoot such a bird if you like to have your gun licence.