PROGRESS ACCOMPLISHED THIS PERIOD

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1 Semi-Annual Report Period Covered: September 1, 21 through February 28, 217 Prepared By: Richard Radigan Title: Monitoring of a Constructed Oyster Reef in the St. Lucie Estuary Agency: Florida Fish & Wildlife Conservation Commission Principal Investigator: Stephen P. Geiger Steve.Geiger@myfwc.com ext 4918 Point of Contact: Janine Morganstern PROGRESS ACCOMPLISHED THIS PERIOD Settled Oyster Density The fall oyster surveys in the St. Lucie estuary were conducted in September 21. Mean live densities of oysters at the Martin County reef increased from approximately 171 oysters/m 2 in April 21 to 281 oysters/m 2 in September 21 (Figure 1). Mean live oyster densities at the natural reef stations increased from a range of 18 to 51 oysters/m 2 in April 21 to 352 to 99 oysters/m 2 in September 21. The percentage of dead oysters at the Martin County reef decreased from 2% to 3% from spring to fall 21. Dead oyster percentages at the three natural reef stations ranged from 3-18% in the spring of 21 which was similar to ranges observed in the fall of 21. Only one station, St. Lucie-central station 3, had an observed increase in dead ratio, from 3% in the spring to 11% in the fall. Mean shell height of live oysters at the Martin County reef (35 mm) was comparable to that of oysters at the natural reef stations where means ranged from 3 to 39 mm. All stations experienced a decrease in mean shell height from spring to fall 21. No problems were encountered during this monitoring period. Spat Recruitment Monthly juvenile spat recruitment monitoring was conducted at the Martin County reef and at the three central estuary natural reefs during this period (Figure 2). Overall, spat recruitment was at or near zero at all stations during this monitoring period. At the Martin county station, the highest observed recruitment rates occurred in September and November when means were.27 and.38 spat/day, respectively. The greatest observed recruitment rate occurred at station 1 in September 21 when the mean rate was 1.13 spat/day. No spat recruitment was observed at the Martin County stations during December and February. No spat were detected at the stations in November and February. Due to damage from hurricane Matthew in October of 21 and subsequent water conditions the recruitment arrays were unable to be located at station 3 in November. Other stations were disturbed but all recruitment arrays were recovered. Reproductive and Disease Monitoring Monthly monitoring of oyster reproductive development (Figure 3) and Perkinsus marinus (dermo) infection prevalence (Figure 4) and intensity (Figure 5) was conducted at all sites during this period. Oysters from the Martin county reef and the natural reefs in the central estuary showed similar reproductive trends during this monitoring period. In general, most oysters from each station were in the spent/recycling stage in September and October and in the indifferent stage in November and December. In January, all sampled oysters from the Martin County station were in the spent/recycling stage; some oysters remained in the spent/recycling stage in February but most were in the indifferent stage. Oysters in all four stages of reproductive development were present at the natural reefs in January and February. Dermo infection prevalence in oysters from the Martin County reef remained relatively stable and only fluctuated between 2% and 4% infected from September 21 to February 217. Infection in oysters from the natural reefs was intermittent and relatively low, with infection rates ranging from % to 4% during this period. The only exceptions occurred in September 21 at station 2 and in December 21 at station 1 when infection rates reached %. Mean infection intensity levels in infected oysters from the Martin County reef and the natural reefs were very light (.5 on the Mackin scale).

2 No problems were encountered during this period. Water Quality Monthly measures of temperature, salinity, ph, dissolved oxygen concentration, and Secchi depth were recorded during this period (Figures, 7, 8, 9 and 1). Water temperatures generally decreased throughout this monitoring period as expected, decreasing from approximately 28 in September to approximately 23 in February. Salinity values were similar among stations in both the natural and the Martin county reef. Heavy freshwater inflows from Hurricane Matthew and other fresh water events in October 21 led to salinities less than 4. from September to November of 21. Salinities steadily and substantially increased to approximately 31 by February 217. Presumably due to the heavy winds associated with a category 4 hurricane and also due to the influx of fresh water, Secchi penetration at the Martin County reef declined substantially during the months of October and November but returned to over % by December 21. Natural reef Secchi depth was comparable, but due to the shallower water at the natural reef stations, Secchi penetration was between 3% and 1% of the water column. No problems were encountered during this period. WORK PLANNED FOR NEXT 3- DAYS Settled Oyster Density The spring oyster surveys are scheduled for March 217. Spat Recruitment Monthly juvenile recruitment monitoring will continue at all stations. Reproductive and Disease Monitoring Monthly monitoring of reproductive development and Perkinsus marinus (dermo) infection intensity will continue at all stations where live oysters are available. Water Quality Monthly monitoring of salinity, temperature, ph, DO concentration, and Secchi depth will continue at all stations. ANTICIPATED NEEDS OR ISSUES At this time, we do not anticipate any needs or issues.

3 4 2 Live Oysters/m % Dead Oysters Shell Height (mm) Mar 215 Jun 215 Sep 215 Dec 215 Mar 21 Jun 21 Sep 21 Dec 21 Mar 217 Mar 215 Jun 215 Sep 215 Dec 215 Mar 21 Jun 21 Sep 21 Dec 21 Mar 217 Figure 1. Mean (± S.D.) number of live oysters (top panels), percentage of dead oysters (middle panels) and shell height of live oysters (bottom panels) sampled at the and at the three natural reef stations. Please note the difference in y-axis range among sites in the top panel.

4 Spat / Shell / Month Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Mar 21 Apr 21 ** ** * May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 2. Mean (± SD) number of oyster recruits per shell each month. Asterisks denote months when samples were not retrieved due to hazardous water conditions. Frequency * * * * Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Mar 21 Apr 21 Indifferent Developing Ripe/Spawning Spent/Recycling May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 3. Percentage of oysters in each of four reproductive categories each month. Reproductive categories are as follows: Indifferent stages and 1, Developing stages 1-4, Ripe/Spawning stages 5 and, and Spent/Recycling stages 7-9. In January 217 the numerical reproductive categories were changed to a 4 point scale as follows: Indifferent stage 4, Developing stage 1, Ripe/Spawning stage 2, Spent/Recycling stage 3.

5 Infection Prevalence Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 4. Percentage of oysters infected with Perkinsus marinus (dermo) each month Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Infection Intensity Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 5. Mean (± S.D.) infection intensity of oysters infected with Perkinsus marinus (dermo) each month. Infection intensity is categorized according to the Mackin Scale.

6 4 4 Temperature ( o C) Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Mar 21 Apr 21 Figure. Temperature recorded each month at stations within the St. Lucie middle estuary. May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Salinity 2 1 Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 7. Salinity recorded each month at stations within the St. Lucie middle estuary. 2 1 Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217

7 ph 8 7 Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Mar 21 Apr 21 Figure 8. ph recorded each month at stations within the St. Lucie middle estuary. May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Dissolved Oxygen (mg/l) Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 * Feb 217 Mar Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 9. Dissolved oxygen concentration recorded each month at stations within the St. Lucie middle estuary. Asterisks indicate when data was unable to be obtained.

8 % Secchi Penetration Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar Mar 21 Apr 21 May 21 Jun 21 Jul 21 Aug 21 Sep 21 Oct 21 Nov 21 Dec 21 Jan 217 Feb 217 Mar 217 Figure 1. Percentage of the water column penetrated by the Secchi disk each month at stations within the St. Lucie middle estuary.