Sadly, Kwin passed away in September 2011 so Frigg is now the only captive-born harbour porpoise in the world :'(
She was one of the 4 porpoises to pass away in Harderwijk in 2011 (Daan, Jordi, Agnes and Kwin). Bram died in late 2010, so out of the 9 porpoises they had in the Brunvisbaai, only 4 remain. It's a tragic story, and no one exactly knows what caused all these deaths. D:
Also, when I first looked at the picture above I thought it was Frigg, until I noticed that the pic was taken in Harderwijk and it's Siepy on the picture (they look so much alike!) =P
Harbour porpoises are also extremely rare outside of Europe, as I visit Vancouver Aquarium almost once a month and they have a female harbour porpoise there (a rescue animal) that is advertised as being the only captive one of its kind in North America.
It's to be said that all of the porpoises in Harderwijk mostly have health issues. All animals brought in to Harderwijk are cared for and tried to be released in the wild again, unfortanetly a lot of animals die in care of can't be released. So they've decided a few years ago to keep them at indeed the old walrus pool. @EuropeDolphins, they dind't have 9 porpoises on show, that would be way to much. 4 porpoises on show is the max. Besides porpoises that occasionally care for other dolphin species(morgan, the killer whale) and last year 2 white-beaked dolphins but both died.
Kwin, Bram, Daan, Jordi, Agnes, Siepy, Michael, Amber and Ellen all lived in the porpoise exhibit at the same time.
Of course, they've had times when they didn't have this many porpoises.
Here they are all together, except Bram: http://www.kraamkamer.nl/image_type/photo/weblog/IMG_8808.JPG?w=800
I haven't seen this picture before! I worked there for a year with them, when I worked there where 4 I think I was there when daan died, but I don't know for sure.