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FEB 2 <br />t. 1986 <br />BOOK 63 FALPl T39 I <br />Mr. Gilmore confirmed that much of what they know regarding <br />the natural ecology of marsh systems prior to impoundment has <br />been learned from studies conducted at the impoundment on the <br />south border of Indian River County mentioned by Mr. Carlson. <br />Harbor Branch participated in these programs with other agencies, <br />and personnel of the Foundation have spent three man years of <br />time in the field conducting these studies. Mr. Gilmore then <br />presented slides showing some of their results. He displayed a <br />diagram of natural marsh and impounded marsh and noted that after <br />the impoundment, they had a reduction in the number of fish <br />species. Mr. Gilmore then displayed pictures of fish, explaining <br />that the resident species are those that breed in the marsh; <br />transient species are those which do not breed in the marsh but <br />use the marsh as a nursery ground for the juveniles. When these <br />areas were impounded, the species which were impacted adversely <br />were snook, tarpon, ladyfish, and striped mullet, all of which <br />are sport and commercial fishes. Blue crab and shrimp also are <br />in the category of transients. <br />Mr. Gilmore informed the Board that principal interest <br />centers in how the fish migrate through these systems. He <br />reviewed what happens in the various seasons, explaining that the <br />maximum recruitment of transient species occurs in the fall when <br />the marsh is inundated. In the low water period, the snook <br />migrate out. The impoundments are now left open totally from <br />September to April because that is the lowest period for mosquito <br />breeding, but during the closed season, there is a flap gate <br />which does not open except at higher water levels. These flap <br />gates can manage water levels in the impoundment. Actually, the <br />design of the gate is not as important as having a culvert in the <br />right location as there are specific regions of the marsh that <br />snook seek year after year. Mr. Gilmore concluded by pointing <br />out that the research would not be possible in the county if they <br />did not have the whole -hearted support of John Beidler and the <br />Mosquito Control District. <br />26 <br />