The current project studies the small fishes occupying Hoffler Creek, a tidal creek with bordering saltmarsh that flows into the James River and is found within Hoffler Creek Wildlife Preserve in Portsmouth, VA.
Water is always present in the creek, but water only floods the marsh vegetation and adjacent mudflats at high tide. In many such systems, small fishes such as killifish (Fundulus species) have been observed moving from the creek at low tide into the marsh and mudflats as they are flooded at high tide.
Any such movement requires energy, which is a cost to the organism, so we would expect that there is a benefit to these fish for moving into these intertidal habitats rather than simply remaining in the subtidal creek habitat throughout the tidal cycle.
One hypothesis for this movement is that these fish consume a greater quantity of food or a different type of food when they are in the intertidal marsh habitat, and we are testing this hypothesis with the first phase of the Hoffler Creek research.
In summer 2008 we sampled killifish (primarily mummichog Fundulus heteroclitus) using minnow traps in the creek at low tide and in the marsh at high tide, collecting over 700 fish in fourteen days in the field.
During the fall, we will be analyzing the stomach contents of these fish in the lab and comparing the quantity of food in the fishes’ stomachs and the diet items they consume while in the two habitat types.
Data will be announced as project nears completion.
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