disappears below 0.5 meter. Due to the dense boat anchor-

age, heavy traffic, increased runoff due to land clearing

and construction, great shoreline alteration and attendant

pollution, water quality in Benner Bay is extremely poor.

Although better, the water quality in the northern part of

the Lagoon is also reduced. The major part of the Lagoon,

however, contains clear water as does the outer portions

of Benner Bay and west Jersey Bay.

 Other zones in the Laoon are characterized by various

algae, grass and coral assemblages (McNulty, 1968}) and con-

tribute to the habitat diversity which makes Mangrove Lagoon

possibly the most complex and varied natural system in the

islands. Not as obvious, but just as important to this eco-

system, is the reef on the south, dominated by Acropora

palate (elkhorn coral) which has been shown to be vitally

important to the Lagoon ecology (Tabb and Michel, 1968;

McNulty, 19609 Michel, 1970) by virtue of its effect on the

local water circulation. The present distribution of bottom

types is shown in Figure 16.

 Benner Bay and the Lagoon are well protected from

strong seas by the reef and cays on the south and by the

eastern tip of St. Thomas and Great and Little St. James

islands to the east and southeast (Figure 1). Water moving

into the area northwesterly looses most of its energy where

the bottom shallows up rapidly between Potto and Cas Cays.


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