Harbor Seal
Harbor seals are not uncommon in the winter, but kayaking is, so don't expect to encounter them when you are out for a paddle.
-- Wikipedia
Common Dolphin
On the other hand, the Common Dolphin prefers warmer weather, and can be seen all through kayaking season. They go south for the winter.
-- Wikipedia
These are some mammals you are likely to see in and around the water.
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The Great Bay Boulevard Wildlife Management Area in Ocean County is 5,982 acres of fresh, brackish and saltwater estuary and islands acquired with funding from hunters and anglers, Green Acres and the sale of waterfowl stamps. The boulevard is a narrow two-lane road that was the beginning of a causeway to the shore that would have connected Great Bay to Atlantic City.
The road was never opened, but now provides access to a great sweep of salt marsh, with opportunities for fishing, birdwatching or simply enjoying the beautiful scenery. Great Bay is considered one of the least-disturbed marine wetland habitats in the northeastern United States.
-- NJDEP
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