Meeting Abstract

P2.40  Thursday, Jan. 5  Community ecology of mangrove rivulus at two west Florida locations MCIVOR, CC; U.S. Geological Survey

Mangrove rivulus (Kryptolebias marmoratus) were captured from closed canopy mangrove forests in two west Florida locations: along a salinity gradient on the Shark River, Everglades National Park, and along an elevation gradient on a mosquito-ditched peninsula in west central Tampa Bay. In both instances they were the most abundant fish taxon captured in buried aluminum trenches placed flush with the forest floor. Mangrove rivulus were present year-round along the Shark River and occurred across a wide range of salinities from near-fresh to near-marine. If abundance is a valid indicator of habitat quality, mangrove killifish selected habitat based on a combination of distance from the nearest permanent subtidal water and intertidal elevation - and thus depth of flooding (Tampa Bay location). A comparison of size frequency distributions in the two locations indicates that Tampa Bay fish are smaller than those in the Everglades, perhaps because of cooler temperatures and longer winters near their northern distributional limit. Tarpon Bay, our uppermost (and lowest salinity) site along Shark River, is a large tidal embayment with 40 km of narrow, fringing mangrove shoreline. If we assume that the habitat we sampled there with three permanently located nets is representative of the remaining shoreline, then extrapolating the means of our rivulus density estimates (7 years of data) indicate that the Tarpon Bay location might contain 30,400 mangrove rivulus. Clearly, the management and scientific communities require basic ecological data from more locations to better ascertain the true conservation status of this widely-used "model" fish.