CHAPTER 7 



INTERFACES WITH OTHER SYSTEMS 



7. 1 MANGROVE 



7.2 CORAL REEF 



Mangroves and seagrass beds occur 

 close to one another within the estuaries 

 and coastal lagoons of south Florida, 

 especially in the clear waters of the 

 Florida Keys. While the importance of 

 nangrove habitat to the estuary has been 

 established (Odun and Heald 1972, 1Q75; 

 Odum et al . 1982), its faunal interactions 

 with adjacent seagrass beds are poorly 

 understood. 



Like the seagrass neadow, the man- 

 grove fringe represents shelter; fishes 

 and invertebrates congregate within the 

 protection of mangrove prop roots. Game 

 fish found in mangroves include tarpon 

 ( Megalops atlanticuj^), snook ( Centropomus 

 unde£i_mal_iJT; Tidy fish ( Flops saurus). 

 crevalle jack (Caranx hippos ), gafftonsail 

 catfish ( Bagre marinus ), and jewfish 

 ( Epinephelus itajara ) (Heald and Odum 

 1970). Undoubtedly, when mangroves and 

 seagrass meadows are in proximity, these 

 fishes will forage over grass. Grey 

 snapper ( Lutjanus griseus )^ sheepshead 

 (Arcliosarmis^ probatocephalus ). spotted 

 seatrout ( Cynoscion nebulosus ), and the 

 red drum ( Sciaenops ocellota ) recruit into 

 seagrass habitat initiallv, but with 

 growth move into the mangrove habitat for 

 the next several years (Heald and Odum 

 1970). All of these fishes have 

 lected over grass. Little work 

 done, however, to explore the 

 interactions between mangroves 

 grass beds. For a detailed review of the 

 nangrove ecosystems of south Florida see 

 Odum et al . (1982). 



been col- 

 has been 

 possible 



and sea- 



Coral reefs occur adjacent to exten- 

 sive turtle grass-dominated grass beds 

 along the full extent of the oceanic mar- 

 gin of the Florida Keys. The most promi- 

 nent interaction involves nocturnal ly 

 active coral reef fishes of several fami- 

 lies feeding over nrass beds at nioht. 

 Randall (1963) noted "that grunts and snap- 

 pers were so abundant on some isolated 

 patch reefs in the Florida Keys that it 

 was obvious that the reefs could not pro- 

 vide food, nor possibly even shelter, for 

 all of them. Longley and Hildebrand 

 (19-11) also noted the dependence (for 

 food) of pomadasyids and lutjanids on 

 areas adjacent to reefs in the Tortugas. 



Typically, both juveniles and adults 

 form large heterotypic resting schools 

 (Ehrlich and Ehrlich 1973) over prominent 

 coral heads or find shelter in caves and 

 crevices of the reef (Figure 24). At dusk 

 these fishes migrate (Ogden and Ehrlich 

 1977; MacFarland et al. 1979) into adja- 

 cent seagrass beds and sand flats where 

 they feed on available invertebrates 

 (Randall 1967, 1968), returning to the 

 reef at dawn. Starck and Davis (1966) 

 list species of the Holocentridae, Lutjan- 

 idae, and Pomadasyidae families as occur- 

 ring diurnal ly on Alligator Reef off Mate- 

 cumbe Key in the Florida Keys, and feeding 

 nocturnal ly in adjacent grass beds and 

 sand flats. As such, these fishes epito- 

 mize what Kikuchi and Peres (1977) defined 

 as temporal visitors to the grass bed, 

 which serves as a feeding ciround (Hobson 

 1973). Starck (1968) discussed further 



75 



