Current Status of Oyster Reefs in Florida Waters: Knowledge and Gaps
Dr. William S. Arnold Florida FWC Fish and Wildlife Research Lab 100 Eighth Avenue SE St. Petersburg, FL 33701 727-896-8626 [email protected] Outline
• History-statewide distribution
• Present distribution – Mapped populations and gaps – Methodological variation
• Ecological status
• Application Need to Know
Ecological value of oyster reefs will be clearly defined in subsequent talks
Within “my backyard”, at least some idea of need to protect and preserve, as exemplified by the many reef restoration projects
However, statewide understanding of status and trends is poorly developed Culturally important- archaeological evidence suggests centuries of usage Long History of Commercial Exploitation
US Landings (Lbs of Meats x 1000) 80000
70000
60000
50000
40000
30000
20000
10000
0 1950 1960 1970 1980 1990 2000 populations quality, andlossof oyster access, degraded water decline dueto lossof oysters landings areon In otherareas ofstate, relatively stablesince1985 landings havebeen (Apalachicola Bay),where Franklin County Most ofthatvalueisfrom fishery in2003 landings valueforFlorida over $2.8millionin important: Economically Statewide:
Pounds of Meats (x 1000) 1000 1500 2000 2500 3000 1000 1500 2000 2500 3000 1000 1500 2000 2500 3000 1000 1500 2000 2500 3000 500 500 500 500 0 0 0 0
1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 Coast West Peninsular Peninsular EastCoast
Year 1
1 Panhandle other 9 9 Franklin County 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 MAPPING
Tampa Bay Oyster Maps
More reef coverage than anticipated, but many of the reefs are moderately to severely degraded
Kathleen O’Keife will discuss Tampa Bay oyster mapping methods in the next talk Caloosahatchee River and Estero Bay Aerial imagery used to map reefs, verified by ground-truthing Southeast Florida oyster maps
• Used RTK-GPS equipment to map in both the horizontal and the vertical. Very labor intensive, but does provide that important vertical dimension
• Contemporaneous ground-truthing provided information not just on location of reefs but also on status at time of sampling
• Subsequent sampling efforts can be designed based upon vertical C.I.’s, sampling density, and expectations of change in the vertical dimension Positives and Negatives
• Better information available on oyster reef distribution and abundance than ever, most developed within last five years
• Various methods have been employed, but common format for results is needed to allow direct comparisons and mapping
• A rapid, 3-D, remote methodology is needed to facilitate repeat sampling and analysis Ecological Status The status of oyster reefs varies Adult considerably from site to site, at least Standing on the SE coast of Florida. stock
Recruitment
Reproduction, disease, condition index
Growth rate Adult Population Abundance and Size
1000 W inter 2005 S um m er 2005 S pring 2006 Fall 2006 800 2
600
400 Mean Live Oysters/m
200
0 TB M L SR SL-N SL-C SL-S LX-N LX-S LW BB Site
100 W inter 2005 Sum m er 2005 Spring 2006 Fall 2006 80
60
40 Mean Shell HeightMean Shell (mm)
20
0 TB M L SR SL-N SL-C SL-S LX-N LX-S LW BB Site Oyster Recruitment
80 20 Tampa Bay Mosquito Lagoon
60 15
40 10
20 5
* 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 20 20 Sebastian River St. Lucie-North
15 15
Recruitment 10 10
5 5 Bimodal in Tampa Bay, peak 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec in June and most recruitment 20 20 in summer. Peak is 3x here St. Lucie-Central St. Lucie-South 15 15 what it is in east coast sites. 10 10
Relatively continuous at 5 5 * 0 0 lower level in Mosquito Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean Spat/Shellper Station Mean 20 20 Lagoon and Lake Worth Loxahatchee-North Loxahatchee-South Lagoon 15 15
10 10
Almost non-existent in 5 5
Sebastian, St. Lucie, and 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 20 20 Biscayne Bay. Lake W orth Biscayne Bay
15 15
Loxahatchee exemplifies 10 10
local variation 5 5
0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Date Oyster Condition Index
10 8 Tampa Bay 6 4 2 0 10 8 Mosquito Lagoon 6 4 2 0 10 8 St. Lucie-Central 6 Condition Index = soft body to 4 2 shell ratio 0 10 8 Loxahatchee-North Generally follows recruitment 6 4 (spawning?) patterns. 2 0
Mean Condition Index Mean 10 In Tampa Bay CI decreases 8 Loxahatchee-South steadily throughout summer 6 4 coincident with continued but 2 0 decreased recruitment 10 8 Lake Worth 6 In contrast, CI relatively 4 2 constant in Mosquito Lagoon 0 as is recruitment pattern 10 8 Biscayne Bay 6 Repro data not yet available but 4 2 link with CI may be more direct 0 Jan Feb Mar Apr May Jun Jul Aug Sep Nov Dec (source of recruits not known) Month Perkinsus marinus Infection Intensity and Occurrence
5 100 40 Tampa Bay 4 80 30 3 60 20 2 40 1 20 10 0 0 0 5 100 40 Mosquito Lagoon 4 80 30 3 60 20 2 40 1 20 10 0 0 0 5 100 40 St. Lucie-Central 4 80 30 3 60 20 Disease Intensity 2 40 1 20 10 0 0 0 5 100 40 Highest prevalence in Loxahatchee-North Infection Intensity 4 80 30 3 60 20 TB although TB and ML 2 40 1 20 10 experience similar 0 0 0 salinity 5 100 40 4 Loxahatchee-South 80 30 Infected SalinityPercent and Mean Perkinsus marinus Perkinsus 3 60 20 2 40 Not much disease in St. 1 20 10 0 0 0 Lucie or Loxahatchee 5 100 40 Lake Worth 4 80 30 3 60 due to extremely low 20 2 40 salinity during summer 1 20 10 0 0 0 5 100 40 Biscayne Bay 4 80 30 Not enough animals at 3 60 20 2 40 several sites and/or on 1 20 10 0 0 0 certain dates for Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec analysis Month Juvenile Oyster Growth and Survivorship
60 100 Tampa Bay 50 Closed 75 40 Open 30 50 20 25 10 0 0 Jul Aug Sep Oct Nov Dec Jul Aug Sep Oct Nov Dec 60 100 Mosquito Lagoon 50 75 40 30 50 20 25 10 0 0 Juvenile Growth and Mortality Jul Aug Sep Oct Nov Dec Jul Aug Sep Oct Nov Dec 60 100 Loxahatchee-North 50 75 40 Cultured animals planted in 30 50 20 cages, ½ open and ½ fully 25 10 enclosed 0 0 Jul Aug Sep Oct Nov Dec Jul Aug Sep Oct Nov Dec 60 100 Loxahatchee-South 50 75 40 Growth rates similar between SurvivorshipPercent Mean ShellMean Height (mm) 30 50 20 sides suggesting little 25 10 physiological impact of cages. 0 0 Jul Aug Sep Oct Nov Dec Jul Aug Sep Oct Nov Dec 60 100 Good growth at most sites Lake Worth 50 75 except Tampa Bay. 40 30 50 20 25 10 Contrast in mortality between 0 0 Jul Aug Sep Oct Nov Dec Jul Aug Sep Oct Nov Dec 60 100 sides and among sites. Most Biscayne Bay 50 75 oysters in open side lost 40 30 50 (washout?). Lots of mortality at 20 25 10 TB site, may be due to different 0 0 origin of planted stock. Jul Aug Sep Oct Nov Dec Jul Aug Sep Oct Nov Dec Date Summary Variation among samples within a reef must be captured when sampling: this dictates large sample sizes and perhaps stratification within reefs
Variation among reefs within a site: location relative to local inputs of nutrients, freshwater, depth, larval sources, etc.
Variation among sites: fundamentals of substrate, landscape, environmental factors although patterns of variation are not always according to conventional wisdom Conclusions Mapping is prerequisite to knowing where the resource is and how it is changing, and this applies to any habitat (e.g., seagrass)
Maps need to be comparative and 3-D
Also need information on biological status, because maps provide a general outline but are less accurate in assessing within-reef status
These data can be used to guide site selection process and identify areas of need, but scale- dependent variation also must be accounted for Questions?
Thanks to the South Florida Water Management District and the United States Fish and Wildlife Service for funding, and to Melanie Parker, Steve Geiger, Mark Gambordella, Sarah Stephenson, Janessa Cobb, and a host of others for doing all of the work.