Here's a harp seal for a new illustration. Harp seals are the ones that start out life cute and fuzzy and white, though they get less fuzzy as they mature to adults.
Google "harp seal" and it's hard not to come across harp seals being clubbed to death, so yes, these are THOSE seals. I found very few images of harp seals swimming, since you just don't get too many scuba divers willing to dive in water that cold, but I did find some great youtube footage of Monk Seals, which are the closest warmer climate seals in body shape to Harp Seals. I just had to fatten them up, and show less neck, and they started looking more like harp seals.