Mangroves as Fish Habitat

Ichthyoplankton and Meroplankton Community Composition of a Restored Mangrove and Salt Marsh Aquatic Preserve in Tampa Bay, Florida (Extended Abstract)

Amanda Croteau

doi: https://doi.org/10.47886/9781934874424.ch15

Mangroves and salt marshes provide vital juvenile habitat for many nearshore and offshore marine species. Florida’s coastal habitats have been severely impacted by coastal development, and Tampa Bay has lost more than 44% of its mangrove and salt marsh habitats (Lewis et al. 1985). Robinson Preserve is one of the largest (197 ha) mangrove and salt marsh restoration efforts in Tampa Bay. Robinson Preserve was originally a coastal wetland that was ditched and drained in the 1920s for agricultural use. In 2006, tidal flow was restored through connections with Perico Bayou, Palma Sola Bay, and the Manatee River. Restoration also involved the planting of native upland and salt marsh vegetation. However, no efforts were made to supplement the aquatic flora and fauna; rather, it was expected that they would colonize the preserve from neighboring populations. Ichthyoplankton and meroplankton abundances were selected as one metric to evaluate the quality of the restored ecosystem as nursery habitat.

A number of methods exist for sampling ichthyoplankton and other large zooplankton, including light traps, benthic sleds, Miller high-speed samplers, push nets, and tow nets. As with any sampling gear, each method has its pros and cons.

Robinson Preserve is shallow (generally <2 m), with complex habitat types and obstructions. It is also a no motor zone. Due to these study site constraints, light traps were selected as the most efficient gear to sample ichthyoplankton and meroplankton within the preserve. The light trap designed by Jones (2006) was redesigned for deployment from shore and scaled down for use in shallow, estuarine systems.

Robinson Preserve was divided into four regions based on water flow and connectivity to surrounding water bodies (1: mixing zone, 2: Palma Sola Bay and Perico Bayou, 3: uplands freshwater drainage, and 4: Manatee River), with one light trap station per region. Sampling occurred quarterly from 2009 to 2013, beginning 3 years after restoration and tidal reconnection. Sampling dates were chosen to detect possible seasonal changes in community composition (winter: January–February, spring: April–May, summer: July–August, and fall: October–November). Light traps were deployed 8 h before sunrise and retrieved the following morning. Samples were preserved with 5% formalin, filtered, and transferred to 70% ethanol. Ichthyoplankton and other large (≥3 mm) zooplankton were identified and enumerated under a dissecting microscope.