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- Title
- RECRUITMENT AND RESTORATION OF THE OYSTER CRASSOSTREA VIRGINICA IN AREAS WITH INTENSE BOATING ACTIVITY IN MOSQUITO LAGOON, FLORIDA.
- Creator
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Wall, Lisa Michele, Walters PhD, Linda J., University of Central Florida
- Abstract / Description
-
Productivity, diversity and survival of estuaries are threatened by explosive coastal population growth and associated recreational activities. One major area of recreational growth has been the number of small pleasure craft motoring in shallow waters at high speeds. On the east coast of Central Florida in the Indian River Lagoon system, intense boating activity occurs year-round and intertidal reefs of the eastern oyster Crassostrea virginica with dead margins (piles of disarticulated...
Show moreProductivity, diversity and survival of estuaries are threatened by explosive coastal population growth and associated recreational activities. One major area of recreational growth has been the number of small pleasure craft motoring in shallow waters at high speeds. On the east coast of Central Florida in the Indian River Lagoon system, intense boating activity occurs year-round and intertidal reefs of the eastern oyster Crassostrea virginica with dead margins (piles of disarticulated shells) on their seaward edges are commonly found adjacent to major boating channels. The cause(s) of the dead margins is unclear. However, the disarticulated shells may be reducing reef sustainability if these surfaces are unavailable for larvae. Recruitment trials were run on eight reefs (4 with dead margins, 4 without) in three 8-week trials in 2001/2002. Significant differences were found for location on reef and season. For survival of recruits, significant differences were found for reef type, location on reef, and season. Sediment loads, percent silt/clay, and relative water motion were all found to be significantly higher on impacted reefs. Spring months were found to be the optimal time for larval recruitment to increase larval set and survival and to also decrease the effects of sedimentation and water motion. Based on these results, experimental restoration began May 2003 to develop an ecologically and economically feasible restoration protocol for this intertidal region. Four different densities of shells (0, 16, 25, 36) were attached to vexar mesh mats (45 X 45 cm) displaying shells perpendicular to the substrate. 360 mats were randomly deployed at one of six identified optimum recruitment locations. Recruitment increased through June and was significantly higher on mats with 36 shells. This was followed by a large, expected decline in recruitment and survival in July/August, due to competition, predation and/or extreme high temperatures. Total live oysters on the restoration mats significantly increased during October 2003 through February 2003. These newly-created oyster reefs are moveable and provide optimal substrate and larval set to be transported post-recruitment to areas resource managers have slated for restoration to aid in reef sustainability. To determine the potential negative effects of flow and sediment levels on oyster larval settlement, which may be associated with an increase in boating actitivity, laboratory experiments were conducted. Eighteen trials, with competent oyster larvae, nine in flowing-water and nine in still-water were run at three sediment levels: no sediment, low sediment, and high sediment loads. Larval settlement was significantly higher in the still-water trials and both high and low sediment loads significantly reduced larval settlement.
Show less - Date Issued
- 2004
- Identifier
- CFE0000113, ucf:46181
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000113
- Title
- Understanding sediment biogeochemistry and the role of juvenile oysters on recently restored eastern oyster reefs.
- Creator
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Locher, Bryan, Chambers, Lisa, Walters, Linda, Kibler, Kelly, University of Central Florida
- Abstract / Description
-
In recent decades, goals for the restoration of eastern oyster (Crassostrea virginica) populations along the eastern coast of the United States have shifted from increasing harvestable oyster fisheries to enhancing the range of ecosystem services provided by oyster reefs. By filtering large volumes of water and releasing nutrient-rich feces and pseudofeces, oysters can locally enhance sediment biogeochemical cycling compared to that of unstructured benthic environments. An ongoing restoration...
Show moreIn recent decades, goals for the restoration of eastern oyster (Crassostrea virginica) populations along the eastern coast of the United States have shifted from increasing harvestable oyster fisheries to enhancing the range of ecosystem services provided by oyster reefs. By filtering large volumes of water and releasing nutrient-rich feces and pseudofeces, oysters can locally enhance sediment biogeochemical cycling compared to that of unstructured benthic environments. An ongoing restoration program in Mosquito Lagoon, FL was leveraged to assess the immediate impacts ((<) 1 year) of restoration on sediment biogeochemical properties of oyster reefs. The first study measured both short-term and long-term pools of carbon, nitrogen and phosphorus on dead, natural and restored reefs periodically over one year. The second study investigated one of the contributions to sediment nutrient pools by comparing feeding and feces/pseudofeces nutrient content of juvenile and older oysters. Results show that inorganic nitrogen and phosphorus pools can change within weeks after restoration and total nutrient pools by 6 months post-restoration. Restored reefs experienced a 136 % increase in ammonium, 78 % increase in total nitrogen, 46 % increase in total phosphorus, and 75 % increase in organic matter concentrations after 12 months of restoration. These nutrient increases were all positively correlated with oyster density, shell length and reef height measured on each reef. When standardized to grams of dry tissue weight, juvenile oysters showed significantly higher rates of chlorophyll-a removal, release of ammonium, and biodeposits with higher concentrations of dissolved organic carbon, nitrite + nitrate, and ammonium. The short-term changes to biogeochemical cycling on eastern oyster reefs within the first year of restoration are important to managers seeking to monitor ecosystem service recovery and overall coastal ecosystem health.
Show less - Date Issued
- 2019
- Identifier
- CFE0007671, ucf:52460
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007671
- Title
- OYSTER REEF RESTORATION: IMPACTS ON INFAUNAL COMMUNITIES IN A SHALLOW WATER ESTUARY.
- Creator
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Harris, Katherine P, Walters, Linda J., University of Central Florida
- Abstract / Description
-
Oyster reefs are important estuarine ecosystems that provide habitat to many species including threatened and endangered wading birds and commercially important fishes and crabs. Infaunal organisms (i.e. small, aquatic animals that burrow in the sediment) are also supported by oyster reef habitats. Infaunal organisms are critical to marine food webs and are consumed by many important species that inhabit coastal estuaries. However, over the past century 85% of shellfish reef habitats have...
Show moreOyster reefs are important estuarine ecosystems that provide habitat to many species including threatened and endangered wading birds and commercially important fishes and crabs. Infaunal organisms (i.e. small, aquatic animals that burrow in the sediment) are also supported by oyster reef habitats. Infaunal organisms are critical to marine food webs and are consumed by many important species that inhabit coastal estuaries. However, over the past century 85% of shellfish reef habitats have been lost, making restoration of these areas vital. Due to their important role in coastal food webs, infauna is hypothesized to be a strong indicator of habitat productivity to document the transition from a dead to a restored and living intertidal oyster reef. Research was conducted in Mosquito Lagoon of the northern Indian River Lagoon system. Three replicate samples were collected from 12 intertidal oyster reefs (four dead, four live, four restored). Samples were collected one-week pre-restoration and one month and six months post-restoration. Infauna was counted and sorted into six taxonomic categories: polychaetes, amphipods, isopods, gastropods, bivalves, and decapods. Reef infaunal abundance increased following restoration: restored reefs became more similar to live reefs one month following restoration. Six months after restoration restored reefs were also significantly different than dead reefs. Live reefs consistently had high infaunal abundance and dead reefs consistently had low abundance, while restored reefs were intermediate. These data suggest restored reefs are more productive than their dead counterparts, with restoration showing a positive trajectory to impact numerous infaunal species and their associated food webs.
Show less - Date Issued
- 2018
- Identifier
- CFH2000366, ucf:45851
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000366
- Title
- QUANTIFYING THE SUCCESS OF EASTERN OYSTER PILOT REEFS IN BREVARD COUNTY, FLORIDA.
- Creator
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Anderson, Lacie, Walters, Linda J., University of Central Florida
- Abstract / Description
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Crassostrea virginica, the eastern oyster, is a native keystone species that inhabits many coastal and estuarine ecosystems along the Atlantic seaboard. Introduction of the eastern oyster into estuarine areas with limited current populations is gaining popularity as a pro-active approach to improve estuarine water quality. In November 2014 and April 2015, a total of five pilot oyster reef treatments were deployed in Brevard County: bagged adult oysters (grown by community members under their...
Show moreCrassostrea virginica, the eastern oyster, is a native keystone species that inhabits many coastal and estuarine ecosystems along the Atlantic seaboard. Introduction of the eastern oyster into estuarine areas with limited current populations is gaining popularity as a pro-active approach to improve estuarine water quality. In November 2014 and April 2015, a total of five pilot oyster reef treatments were deployed in Brevard County: bagged adult oysters (grown by community members under their docks through oyster gardening) collected in fall 2014 and spring 2015, bagged clean shell, oyster restoration mats, and empty plots (control). Locations of deployment included a Merritt Island impoundment (Marsh Harbor), Nicol Park (Port St. John), and Scout Island (Melbourne Beach). Prior to deployment, we collected morphometric data (shell length, weight) on all gardened oysters. Abiotic factors including salinity, air and water temperature, and wind speed were collected monthly. During quarterly sampling at each site, morphometric data were collected for all live oysters, surviving and newly recruited. Results show survival of gardened oysters and natural recruitment differed by and depended greatly on the within-site location of each reef. In areas with no recruitment and limited gardened oyster survival, regular deployment of gardened oysters is needed for long term success. In areas with natural recruitment, bagged, clean shell or oyster restoration mats are most successful. Future restoration sites should be tested prior to any large-scale oyster deployments.
Show less - Date Issued
- 2016
- Identifier
- CFH2000059, ucf:45557
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000059
- Title
- DETERMINING FACTORS THAT INFLUENCE SMOOTH CORDGRASS (SPARTINA ALTERNIFLORA LOISEL) TRANSPLANT SUCCESS IN COMMUNITY-BASED LIVING SHORELINE PROJECTS.
- Creator
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Carrion, Steven A, Walters, Linda J., University of Central Florida
- Abstract / Description
-
Efforts to mitigate shoreline erosion through living shoreline methods along the USA Atlantic seaboard have often incorporated the cultivation and transplantation of smooth cordgrass, Spartina alterniflora. Assessments of these transplants at several sites in the Indian River Lagoon have shown that survival is variable after a year (survival: 10-93%). Lower survival has been attributed to environmental variables such as dislodgement by wave energy, and transplant shock due to salinity changes...
Show moreEfforts to mitigate shoreline erosion through living shoreline methods along the USA Atlantic seaboard have often incorporated the cultivation and transplantation of smooth cordgrass, Spartina alterniflora. Assessments of these transplants at several sites in the Indian River Lagoon have shown that survival is variable after a year (survival: 10-93%). Lower survival has been attributed to environmental variables such as dislodgement by wave energy, and transplant shock due to salinity changes from cultivation to estuarine conditions. To improve living shoreline projects, we examined the effects of cultivation salinity (0 ppt, 15ppt) on transplantation success, and the success of anchoring plants to biodegradable mats (Jute mesh, 5 individuals per 50 cm2) and utilizing oyster bags as breakwaters in facilitating reestablishment of new transplants. Spartina alterniflora individuals were grown under salinity treatments for 20 weeks; plants grown in 15 ppt produced new shoots with significantly greater heights than those grown in freshwater. The plants were then transplanted to two sites in the IRL, and monitored after four weeks. After four weeks there was a greater net increase in stem density and larger decrease in plant height for plants grown in 15 ppt. Jute-mesh mats and oyster bags did not impact growth or survival of transplants. Low-saline (15 ppt) conditions increased shoot growth of the project by 50% in four weeks at a cost of 30 cents per additional shoot produced by an individual. Longer-term monitoring will determine if benefits persist or decrease over time, and if the cost is justified by the benefits.
Show less - Date Issued
- 2016
- Identifier
- CFH2000068, ucf:45538
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000068
- Title
- ASSESSING THE IMPACT OF OYSTER REEF AND LIVING SHORELINE RESTORATION ON MACROINVERTEBRATE COMMUNITY ASSEMBLAGES IN MOSQUITO LAGOON, FLORIDA.
- Creator
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Searles, Adam, Cook, Geoffrey, University of Central Florida
- Abstract / Description
-
As the world continues to experience substantial rates of habitat loss, habitat restoration has become of prime interest to ecologists worldwide. Restoration has shown to be successful in recovering targeted components of certain ecosystems but it is important to achieve a holistic understanding of the resulting ecological impacts it has on communities. To address this, four oyster reefs and three living shorelines were restored during the summer of 2017. These sites, along with four dead...
Show moreAs the world continues to experience substantial rates of habitat loss, habitat restoration has become of prime interest to ecologists worldwide. Restoration has shown to be successful in recovering targeted components of certain ecosystems but it is important to achieve a holistic understanding of the resulting ecological impacts it has on communities. To address this, four oyster reefs and three living shorelines were restored during the summer of 2017. These sites, along with four dead oyster reefs, four living oyster reefs, and three undisturbed (control) living shorelines, were sampled before restoration and regularly post-restoration for one year using lift nets. Macroinvertebrates were collected and enumerated in the lab. Diversity indices, community composition, and similarity percentages were then calculated and compared across treatments, time, and treatment-by-time. Live reefs displayed significantly higher species richness and Shannon diversity than restored and dead reefs. Simpson diversity did not differ between live and restored oyster reefs but both were significantly higher than dead reefs. Though not statistically detectable, species richness and Shannon diversity on restored reefs were relatively similar to dead reefs before restoration but became increasingly similar to live reefs over the course of the study. Additionally, analyses revealed significantly different community compositions between live reefs and restored reefs, as well as between live and dead reefs. Living shorelines showed no significant differences in diversity indices but did experience similar seasonal fluctuations in diversity across treatments. Just as with oyster reefs, restored and control living shorelines harbored significantly different communities across time. The findings of this study emphasize the need for dedication to thorough monitoring and multi-metric evaluation of success in restoration efforts. This study and future research will equip resource managers with ways to quantify the effects of restoration that will consider several important ecosystem components.
Show less - Date Issued
- 2019
- Identifier
- CFH2000545, ucf:45646
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000545
- Title
- PREDATION ON THE EASTERN OYSTER CRASSOSTREA VIRGINICA ON INTERTIDAL REEFS AFFECTED BY RECREATIONAL BOATING.
- Creator
-
Stiner, Jennifer, Walters, Linda, University of Central Florida
- Abstract / Description
-
Widely regarded as a keystone species and ecosystem engineer, the eastern oyster Crassostrea virginica plays a vital role in estuarine environments. Complex, three-dimensional oyster reefs act as havens for biodiversity and contribute to ecological processes. Recently, concern for this resource has arisen in Mosquito Lagoon, Florida, the southernmost limit along the Atlantic coast for undisturbed, intertidal reefs of C. virginica. Since the 1990s, intense recreational boating activity has...
Show moreWidely regarded as a keystone species and ecosystem engineer, the eastern oyster Crassostrea virginica plays a vital role in estuarine environments. Complex, three-dimensional oyster reefs act as havens for biodiversity and contribute to ecological processes. Recently, concern for this resource has arisen in Mosquito Lagoon, Florida, the southernmost limit along the Atlantic coast for undisturbed, intertidal reefs of C. virginica. Since the 1990s, intense recreational boating activity has caused atypical dead margins (mounds of disarticulated shells) to emerge on the seaward edges of oyster reefs located along major navigational channels. Once dead margins are formed, little is known about their influence on biotic composition and interactions on oyster reefs. This study focused on the affect of dead margins on: (1) mobile species biodiversity and distribution, (2) reef architecture, and (3) the affect of structural variables on predation of juvenile oysters. To determine if dead margins influenced the biodiversity of mobile species on oyster reefs, lift nets (1 m2) were deployed within Mosquito Lagoon for one year (June 2004 - June 2005). These nets (5/site) were deployed on the back-reef areas of six reefs (3 reference reefs and 3 reefs containing dead margins). To simulate reef habitat, one and a half liters of live oysters were placed within each net. Lift nets were checked monthly and surveyed for all mobile species. The resulting data were assimilated into a species inventory containing 65 species of fishes, mollusks, crustaceans, worms, and echinoderms. The two most abundant species present on reefs in Mosquito Lagoon were the big-claw snapping shrimp Alpheus heterochaelis, a filter-feeder, and the flat-back mud crab Eurypanopeus herbstii, a predator of oyster spat. Contrary to expections, analyses of community metrics showed that dead margins did not significantly affect the biodiversity of back-reef areas on oyster reefs. Modified lift nets (0.25 m2) were placed on six different oyster reefs (3 reference reefs and 3 containing dead margins) to test if dead margins affected the distribution of mobile species inhabiting oyster reefs. Nine nets were arranged to cover three separate areas of each reef: the fore-reef (3 nets), mid-reef (3 nets), and back-reef (3 nets). Half a liter of oyster shells were placed inside each net. These nets were checked weekly, for five weeks and species richness, density, and biomass were recorded. Analyses revealed that all community metrics were significantly higher on reference reefs than reefs affected with dead margins. Further, a significant drop in all three metrics was seen on the mid-reef area of affected reefs. The absence of species on this area is hypothesized to be due to a lack of water, shade, and habitat complexity. To document architectural differences, two types of transects were run along five reference reefs and five reefs with dead margins. First, quadrat transects determined the percent of live oysters, the percent of shell clusters, topographic complexity (using chain links), and the angle of shells on each reef type. Transect lines were stretched parallel to the water line and covered all three reef areas (fore-reef, mid-reef, and back-reef). The results showed reference reefs to have approximately four-fold more live oysters, approximately twice as many shell clusters, and significantly greater topographic complexity. Numbers of live oysters and shell clusters were greater on the fore-reef and back-reef areas of both reef types. Second, laser transects were used to record reef profiles and the slope of fore-reef areas. Transect lines were stretched perpendicular to the water line and every 20 cm the distance between the lagoon bottom and reef top was measured. Vertical reef profiles and fore-reef slopes were significantly different between reference reefs and reefs with dead margins. Dead margins compressed reef widths, increased center peaks, and increased slopes on the fore-reef area by two-fold. Lastly, field experiments were conducted to determine the affect of dead margins on the vulnerability of oyster spat to predation. Structural variables (e.g. shell orientation, single versus shell clusters, reef slope) were manipulated and effects on oyster mortality were observed. Three predators were tested: the blue crab Callinectes sapidus, the common mud crab Panopeus herbstii, and the Atlantic oyster drill Urosalpinx cinerea. Structural variables did not have a significant influence on oyster mortality; however, a significant difference was established between predators. Panopeus herbstii consumed the most juvenile oysters, followed by U. cinerea and then C. sapidus. Together, these findings document ecological implications of dead margins on C. virginica reefs and reinforce the urgent need for enhanced regulations and restoration. If the intensity of recreational boating remains unregulated, dead margins will continue to increase. Thus, in order to maintain the diversity and productivity of Mosquito Lagoon, it is crucial to fully understand how dead margins alter the biogenic habitat and biotic communities of oyster reefs.
Show less - Date Issued
- 2006
- Identifier
- CFE0001059, ucf:46790
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001059
