Most of those Seals' pictures were taken with a 500 mm lens, sometimes added with an 1.2 extender. The Harbor Seals are WILD animals, and deserve to be respected. If you notice anyone harrassing them please contact the The National Marine Fisheries Service at 1-800-853-1964.
For more information on the Harbor Seals of Ja Jolla, check out La Jolla Friends of the Seals (LJFS) website.