| Mangrove systems are widely recognized as an important habitat for juvenile fish and crustacea yet there is little consensus concerning the exact features which contribute to their “nursery” function. This research, consisting of several interrelated studies conducted from 1996–2002, was designed to explore the role of the mangrove canopy in influencing the intertidal distribution of fishes. This work included the employment of field simulated mangrove structures as a means to discern habitat selection cues as well as the first instance of experimental manipulation of a mangrove canopy to note subsequent alterations in the mangrove associated fish assemblage.; From 1996–2002, a series of experiments designed to examine the relative influence of shade, structure, and mangrove litter on the distribution of fishes was conducted in the intertidal zone of a mangrove embayment in Tampa Bay, Florida. While the presence of mangrove root structure was not found to be a significant factor, fish were strongly associated with shading and litter. This relationship was not constant over all water depths; fish associated more closely with shaded plots at greater water depths, while litter covered plots were abandoned with greater depth. Tethering trials indicated that this may be due variable predation pressure that increases with water depth up to 60 cm and then subsequently declines.; From 1998–2000, a study of the impact of an anthropogenic source of canopy damage, horticultural mangrove trimming, was conducted at twelve sites in Rookery Bay. Florida. In this study, after a single year of baseline data collection (e.g. litter fall, fish density, and fish biomass) at these sites, the mangroves at one half of the sites were trimmed, removing a substantial portion of the canopy (approximately 47%). An additional year of data collection was then conducted. The results indicate that while mangrove trimming reduces litter fall rates, there was no subsequent change in fish density, biomass, or species composition that could be linked to the canopy damage. These results suggest that given the shallow water depths found beneath New World mangroves, canopy damage is unlikely to cause profound changes in the utilization of these intertidal habitats by fishes. |
