The kayak has a topside axial enclosure, which may be rendered watertight and used as a bait tank or other liquid container, and at least one additional enclosure positioned transversely to the axial enclosure, which may or may not be watertight. In the preferred embodiment, a second additional enclosure is positioned transversely to the axial enclosure on the opposite side from the first additional enclosure. The enclosures are preferably configured with the upper surfaces of their covers at a single level, so that they may be used collectively as an extended, relatively flat fishing seat. Various access and sealing means are selectively provided for the respective enclosures. For example, a removable transparent access port may be included within the cover of the axial enclosure. In some embodiments, a circulation pump is provided to discharge within the axial enclosure. Likewise, the transversely positioned enclosure(s) may be selectively removable. In some embodiments, those enclosures may, upon removal, expose an opening to the kayak's internal cargo hatch.