Caloosahatchee River and Estuary Research

Second Quarterly Report To South Florida Water Management District

District Agreement CP-050281

Submitted To:

TOMMABA~S . FORT MYERS SERVICE CENTER SOUTH FLORIDA WATER MANAGEMENT DISTRICT 2301 MCGREGOR BLVD. FORT MYERS, FL 33901

Submitted By: Dr. Brad Robbins . . Mote Marine Laboratory . 1600 Ken Thompson Parkway . Sarasota, FL 34236

Mote Marine Laboratory Technical Report No. 1010

April 15, 2005 15 April 2005

Tomma Barnes Fort Myers Service Center South Florida Water Management District 2301 McGregor Blvd Fort Myers, FL 33901 [email protected]

Ref: District Agreement CP-050281, Caloosahatchee River and Estuary Research, Quarterly Letter Report

Dear Ms. Barnes:

Please accept this letter and accompanying material as Mote Marine Laboratory's second Quarterly Letter Report for Caloosahatchee River and Estuary (CRE) research. The data contained within are summaries of raw numbers that have not been checked for accuracy. The data are an incomplete sampling of the HF (high flow) sample period and thus only partially represent that time period.

Introduction

Theobjective of this research is to continue examining the dynamics of SAV and its faunal associated community (e.g. juvenile fish) with regard to changes in salinity and season. Results of this research will provide information applicable to restoration and management efforts, with the goal·of incorporating research-derived predictions of changes in community structure associated with habitat changes. The research reported here is a continuation of two studies (C-12109 & C-12836) funded by the District, which ended September 31, 2004. Both of these studies were awarded to Mote Marine Laboratory (MML) with Dr. Brad Robbins, Manager ofMML's Landscape Ecology Program acting as a co-PIon C-12109 and as the PIon C-12836.

The research addresses four (4) specific questions: 1. How do salinity fluctuations affect SAV habitats (including the recovery of Vallisneria americana); 2. How do salinity fluctuations affect fish population densities within SA V habitats; CP-050281, Caloosahatchee River and Estuary Research Robbins, PI

3. Does faunal utilization of SAV habitats vary with SAY species, habitat configuration, salinity, and/or season; and 4. What is the impact of timed water releases on the composition and densities of fish species in SAV beds?

The objective of Year One is to combine the two previous studies (C-12109 & C- 12836) into a comprehensive research program. All sites are being sampled three times during each sampling period, with each period corresponding to three District-defined seasonal periods: 1) MarchiApril to June/July - high recruitment (HR) 2) July to November - high flow (HF) 3) November to March -low productivity (LP)

Data Collection Summary Task 1: Site selection This task has been completed. A description of sampling sites can be found in Quarterly Report Y 1Q 1.

Task 2: Flora Both floral species, Vallisneria americana and Ruppia maritima, found in the River displayed an increase in the number of sites they were found when compared to the previous sampling period. Specifically, the percentage of sites where V americana increased to 56% (Figure 1) from 22% found during the previous sampling period (HFY1). Similarly, R. maritima increased to 19% from <10%. Within the estuary, Halodule wrightii and Thalassia testudinum were found at each of the sampling sites (as defined by their dominant seagrass species: Halodule, Syringodium, and Thalassia) during the LP sampling period (Figure 2). In contrast, Syringodium jiliforme was only found at the Syringodium sites (Figure 2). Mean shoot density was seen to vary temporally within the sampling period (Figure 3). This variation was by species and site. Canopy height (reflected by mean maximum blade length; Figure 4) also varied through time with an increase seen. Seagrass biomass by sites without regard for species was also seen to increase temporall