1. Jay R. Leverone1 and Gary Raulerson2
First year monitoring of newly constructed oyster platforms in Sarasota Bay, Florida
Jay R. Leverone1 and Gary Raulerson2
1Mote Marine Laboratory, Sarasota, FL
2Sarasota Bay Estuary Program, Sarasota, FL
Introduction
The Sarasota Bay Estuary Program has been interested in enhancing valuable coastal habitats since the Program’s inception. Oyster bars, as habitat, have been receiving increased attention recently and a program to identify, permit and create oyster habitat within the estuary began in Two sites (White Beach and Turtle Beach) were selected for creating new oyster habitats. North Creek, an area with extensive, healthy oyster populations, was chosen as a reference site. In 2005, permits were approved, materials purchased, and designs and configurations for each habitat project developed. New oyster habitat was constructed at each site during August 2005 (Fig 1).
The objective of this study was to monitor oyster spat recruitment to each habitat. This information will help determine the optimum time for creating new habitat and/or placing new material on existing platforms.
Results (Cont)
Retrieval Date
Turtle Beach
White Beach
North Creek
26-Sep-05
24-Oct-05 3
5-Dec-05
2-Jan-06
6-Feb-06
27-Feb-06
20-Mar-06
14-Apr-06
5-May-06
26-May-06
16-Jun-06
11-Jul-06
3-Aug-06 16
Restoration Sites
White Beach
Table 1. Number of spat on settlement plates at the two created oyster platforms (Turtle Beach and White Beach) and the reference site (North Creek) during the first year of monitoring.
Little Sarasota Bay
Materials and Methods
New habitat was created using the oyster “sausage” method. Sausages were deployed in different configurations at each site. Recruitment monitoring began immediately after habitat construction was completed. Monitoring consisted of two components: 1) the installation and retrieval of removable settlement plates and 2) the collection of a limited number of shells from sausages at each restoration site (Fig 2). The settlement plates allowed us to monitor spat recruitment over time while the shells in the oyster sausages enabled us to assess how well the habitat structures functioned in attracting new oyster recruits.
Settlement plates (15 x 15 cm2) were suspended vertically in the water column one foot off the bottom. Four plates were deployed at each site. Each month, two plates were removed and replaced by new, clean plates. The following month, the other two plates were exchanged. This allowed each set of plates to “soak” for two months, allowing more time for oyster spat to settle and grow. By overlapping the exchange frequency of plates, episodes of recruitment could be assigned to a particular month. Plates were air dried for several weeks. The number of oyster spat (and barnacles) per plate were counted.
Turtle Beach
North Creek
Figure 3. Mean number of oyster spat per shell at the two oyster habitat restoration sites. Total number of shells collected each month ranged from six to ten per site
Figure 1
Conclusions
The presence of viable oyster spat at both sites indicates that we were successful in creating two functional oyster habitats in Little Sarasota Bay during Recruitment was observed during summer/fall in 2005 and 2006 (Table 1). No recruitment was observed during the spring. Shells at the White Beach had more that twice the number of spat as shells at Turtle Beach (Fig 3). We observed an increase in the size of attached oysters over time, although no measurements were taken. The “substrates” we selected to monitor temporal spat recruitment did not perform as efficiently as anticipated; therefore, we have switched to suspended oyster shell for monitoring future recruitment.
Results
Year 1
Year 2
Oyster Shells
Oyster Strings
Settlement Plates
Dec, 2005
Feb, 2006
Apr, 2006
Jun, 2006
Aug, 2006
Figure 2