**2. Temperate estuary "Delaware Inland Bays" characteristics and challenges**

Delaware's 'Inland Bays' (DIB), similar to many of the coastal lagoons in the Mid-Atlantic region of the United States (U.S.), have been experiencing the impacts of chronic eutrophication and sediment erosion resulting from several decades of poor land use practices including housing development, agriculture and sustained nutrient input from within the surrounding watershed [1]. The cumulative impacts of these effluents from anthropogenic activities has degraded water quality and reduced the diversity and abundance of various species of aquatic life including fishes, invertebrates and submerged aquatic vegetation [2]. As a keystone species in estuarine bays, oysters provide important ecological services in these systems by filtering suspended particulates from the water column, increasing water clarity, and removing nutrients from eutrophic waters [3, 4]. Oyster reefs also serve as a valuable component of estuarine ecosystems, offering unique habitats for many ecologically, economically, and recreationally important species [2]. The bay degradation has led to the dramatic decline of the local oyster *Crassostrea virginica* populations since the late 1800s [4–7].

**1. Introduction**

34 Aquaculture - Plants and Invertebrates

**challenges**

is one of the many activities people conduct.

Coastal areas are home to a wealth of economic and natural resources and are the most developed areas in the nation with continuous increase in human population. Over 50% of the nation's population resides in 17% of the U.S. coastal areas. In light of these numbers, it is critical that consideration be given to the impact humans have on these coastal ecosystems and to the methods which are currently being utilized to enhance and restore these coastal habitats. There are various ways people use coastal areas for their needs. Shellfish aquaculture

In this chapter, we compare and contrast the health and status of the Eastern oyster, *Crassostrea virginica*, in two east coast estuaries: the Delaware Inland Bays, Delaware and Apalachicola Bay, Florida. Many ecological services which are provided by oysters, such as their filtration, benthic and pelagic coupling, and habitat forming characteristics, have been extensively studied and discussed. Oysters increase water clarity and quality by filtering sediments and algae, and removing nutrients such as nitrogen and phosphorous. The Eastern oyster was once a fixture of the local economies on the east coast however, combined effects from over harvesting, habitat destruction, and diseases such as Dermo and MSX have caused oyster populations to decline dramatically. Along with this decline in oyster populations, coastal lagoons in east coasts of the United States have been experiencing rapid development within the coastal watershed increasing eutrophication events. The once abundant oysters filtered algae and sediments, removed phosphorus and nitrogen, and played a vital role in the ecosystem that could help to counteract the increasing pressure on the watersheds. Many regional economies in the United States of which the harvest

of Eastern oysters was a major component, struggled with the collapsed fishery.

facing the increased presence of aquaculture in these estuary systems.

**2. Temperate estuary "Delaware Inland Bays" characteristics and** 

Delaware's 'Inland Bays' (DIB), similar to many of the coastal lagoons in the Mid-Atlantic region of the United States (U.S.), have been experiencing the impacts of chronic eutrophication

In response to these issues, oyster aquaculture has grown and is now a major part of the working waterfront where traditional wild oyster populations used to thrive. In recent years, farm-raised oysters have become a more sustainable operation than commercial fishing. Oyster aquaculture has benefits beyond supporting human economies and diets. Oyster aquaculture can provide many of the same ecological services as oyster reefs, which are a valuable component of estuaries worldwide, serving as a unique habitat for many ecologically and economically important species. Research focusing on the ecological effects of oysters raised with commercial aquaculture equipment is becoming more prolific as the industry moves away from a wild harvest fishery to a cultivated product. However, there is a critical need to better understand the dynamics of local waters to enhance potential fisheries for both estuaries. The oyster fishery may be recouped if the demand for oysters is supplied with oysters from aquaculture operations. Our primary goal in this chapter is to increase awareness about the potential benefits and some of the challenges In response to the plummeting populations, 'oyster gardening' programs have taken root throughout the estuarine ecosystems of the Mid-Atlantic, including Delaware Inland Bays (*see* **Figure 1a**), in an effort to restore the native oysters for their ecological and commercial contribution to the health and viability of coastal estuaries. Many community-based estuary programs have involved volunteers to help rear larval oysters into healthy adults for reef restoration and it is no different in Delaware Inland Bays [5, 9, 10]. Volunteers living in the local communities surrounding the watershed in the Delaware Inland Bays place floating baskets of oysters at the ends of their docks to allow the filter-feeders a safe haven to grow from small, young spat into thriving adult oysters (*see* pictures in **Figure 1b**). Community members throughout southern Delaware are being given the unique opportunity to observe first hand many of the important ecological services provided by oysters and learn about the local watersheds.

With a shoreline of approximately 418 km, no part of Delaware more than 13 km from tidal waters, with Delaware Inland Bay consisting of three shallow coastal Bays: Rehoboth, Indian River, and Little Assawoman Bays. The combined surface water area of the three bays covers 83 square km with an average depth of 1.2 m. The Delaware Inland Bays (DIB) supports a small commercial hard clam and blue crab fishery along with weakfish, spot, bluefish, and Atlantic menhaden representing the majority of the commercial finfish catch in the Delaware Inland Bays and a variety of other commercially and environmentally important aquatic species [64].

Associated problems in those bays are similar to other Mid-Atlantic estuaries including eutrophication, high turbidity, sedimentation, periodic hypoxic/anoxic conditions, annual fish kills, low species diversity, and physical disturbances due to anthropogenic activities especially in the man-made canal systems. According to Delaware Inland Bays Estuary Program Report [11] and Chaillou et al. [1], approximately 80% of freshwater flow is from groundwater and the sandy, permeable soils of the watershed have led to widespread contamination of groundwater by nitrates in Delaware Inland Bays. Flushing rates may vary widely among the three bay areas, being as low as 1–7 days for Little Assawoman while those for Rehoboth and Indian River Bays may be as high as 80 and 100 days, respectively.

Delaware Center for the Inland Bays Report [12] stated agriculture as the largest use of land (32%) followed by developed/developing lands (22%), forested lands (17%) and wetlands and waters (16% and 12%) with significant loss of forest lands recorded in the watershed between

have been described as "unflushable." Martin et al. [15] reported that many of these canals are anoxic/hypoxic and subsequently lack higher trophic levels. **Table 1** describes the relative contribution of total nitrogen and phosphorus sources in the Inland Bays watershed and this outcome has not changed since the first time it was assessed in 1993 with nitrogen levels exceeding the targeted goal for all three bays in the Inland Bays. Agriculture is also listed as the leading contributor for the overall nitrogen and phosphorus sources in the Delaware Inland Bays [11]. **Figure 3a** shows the high nitrogen imputes, 6 times the healthy limit in Indian River due to fertilizer applications for agriculture and lawns in residential areas, animal waste and manure, and human wastewater [14, 16]. Eutrophication and degraded water quality impacts species present in this ecosystem [14]. **Figure 3a** displays the early nitrogen loadings in the Delaware Inland Bays from non-point source pollution [14]. This eventually causes regime shift from rich benthic flora and fauna to increase planktonic and microbial organisms [17]. **Figure 3b** shows the phosphorus loadings with no clear trends, according to Walch et al. [14], this may be credited to improved nutrient management on farms and the conversion of cropland to

Are Aquaculture Practices Sustaining Our Goal to Restore Oysters (*Crassostrea virginica*)?

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37

Previous research suggested that [8, 18–24], Delaware's Inland Bays are in urgent need of the ecological services offered by oysters. Because these bays are very shallow (1 to 2.4 meter depth) and are poorly flushed by tidal movement, they are especially sensitive to environmental changes. Increases in pollutants, changes in salinity due to increase frequency of precipitation or drought events, climate change related fluctuation in water temperature, episodic hypoxic and anoxic conditions, as well as harmful algal blooms can all have detrimental effects on native oyster population. Proper site selection for oyster and reef restoration is essential and inclusive of other environmental limitation and issues. Over 50% of the available land in Delaware is used for agriculture with a long history of agricultural production of

**Figure 2.** a. Changes in land use of the Inland Bays watershed from 1992 to 2007 [13]. b. Changes in land use of the Inland

development with storm water controls.

Bays watershed from 2007 to 2012 [14].

poultry, corn, soybeans, and other crops (*see* **Table 2**).

**Figure 1.** a. Delaware's Inland Bays showing oyster gardening locations, rip-rap planting locations, and known wild oyster locations [8]. *Map by Frank Marenghi.* b. Various oyster gears and oysters in rip-rap pictures indicating some natural recruitment is happening in Delaware Inland Bays. *Pictures by Frank Marenghi and Brian Reckenbeil.*

1992 and 2007 (*see* **Figure 2a**). **Figure 2b** shows the changes in the land use from 2007 to 2012, we can see improvement in the land use pattern for wetland lost. According to Delaware Inland Bays Estuary Program Report [11], the 200 hectares of dead-end canals within this system have been described as "unflushable." Martin et al. [15] reported that many of these canals are anoxic/hypoxic and subsequently lack higher trophic levels. **Table 1** describes the relative contribution of total nitrogen and phosphorus sources in the Inland Bays watershed and this outcome has not changed since the first time it was assessed in 1993 with nitrogen levels exceeding the targeted goal for all three bays in the Inland Bays. Agriculture is also listed as the leading contributor for the overall nitrogen and phosphorus sources in the Delaware Inland Bays [11].

**Figure 3a** shows the high nitrogen imputes, 6 times the healthy limit in Indian River due to fertilizer applications for agriculture and lawns in residential areas, animal waste and manure, and human wastewater [14, 16]. Eutrophication and degraded water quality impacts species present in this ecosystem [14]. **Figure 3a** displays the early nitrogen loadings in the Delaware Inland Bays from non-point source pollution [14]. This eventually causes regime shift from rich benthic flora and fauna to increase planktonic and microbial organisms [17]. **Figure 3b** shows the phosphorus loadings with no clear trends, according to Walch et al. [14], this may be credited to improved nutrient management on farms and the conversion of cropland to development with storm water controls.

Previous research suggested that [8, 18–24], Delaware's Inland Bays are in urgent need of the ecological services offered by oysters. Because these bays are very shallow (1 to 2.4 meter depth) and are poorly flushed by tidal movement, they are especially sensitive to environmental changes. Increases in pollutants, changes in salinity due to increase frequency of precipitation or drought events, climate change related fluctuation in water temperature, episodic hypoxic and anoxic conditions, as well as harmful algal blooms can all have detrimental effects on native oyster population. Proper site selection for oyster and reef restoration is essential and inclusive of other environmental limitation and issues. Over 50% of the available land in Delaware is used for agriculture with a long history of agricultural production of poultry, corn, soybeans, and other crops (*see* **Table 2**).

**Figure 2.** a. Changes in land use of the Inland Bays watershed from 1992 to 2007 [13]. b. Changes in land use of the Inland Bays watershed from 2007 to 2012 [14].

1992 and 2007 (*see* **Figure 2a**). **Figure 2b** shows the changes in the land use from 2007 to 2012, we can see improvement in the land use pattern for wetland lost. According to Delaware Inland Bays Estuary Program Report [11], the 200 hectares of dead-end canals within this system

**Figure 1.** a. Delaware's Inland Bays showing oyster gardening locations, rip-rap planting locations, and known wild oyster locations [8]. *Map by Frank Marenghi.* b. Various oyster gears and oysters in rip-rap pictures indicating some

natural recruitment is happening in Delaware Inland Bays. *Pictures by Frank Marenghi and Brian Reckenbeil.*

36 Aquaculture - Plants and Invertebrates


According to U.S. Environmental Protection Agency [16], two areas of concerns have been identified as critical issues for DIB: eutrophication and habitat loss primarily due to urbanization, agricultural activities, and low flushing rates. Specifically, primary sources of nutrients include, a point and non-point sources in watershed, septic systems, animal wastes and fertilizers from agricultural lands. Excess nutrients, nitrogen and phosphorus deteriorated the bay aquatic life were managed using Total Maximum Daily Loads (TMDLs) for nitrogen and phosphorus for the Indian River and its Bay and Rehoboth Bay in 1998 and the Little Assawoman Bay in 2004. According to Delaware Center for the Inland Bays Report [27] "to meet the load reductions required by the TMDLs, water quality goals include the elimination of all point sources if nutrient loading to the water bodies, along with a 40% reduction in

Are Aquaculture Practices Sustaining Our Goal to Restore Oysters (*Crassostrea virginica*)?

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39

**Table 2.** Delaware farms, their acreages, and types of farming practices [25].

**Table 1.** Relative contributions of nitrogen and phosphorus sources in the Inland Bays (Courtesy of [11]).

These adverse environmental impacts have detrimental effects on overall habitat quality and put tremendous pressure on local aquatic habitats. As Delaware's coastal landscape continues to develop in a low-density and sprawling manner, the health of valuable natural resources, many of which sustain local economies, is increasingly at risk. Managing the demands for protecting critical habitat areas and managing water resources are complex and continuous challenges in Delaware [26].

**Figure 3.** a. Yearly nitrogen loadings in the Delaware Inland Bays from non-point source pollution [14]. b. Yearly phosphorus loadings in the Delaware Inland Bays from non-point source pollution [14].

According to U.S. Environmental Protection Agency [16], two areas of concerns have been identified as critical issues for DIB: eutrophication and habitat loss primarily due to urbanization, agricultural activities, and low flushing rates. Specifically, primary sources of nutrients include, a point and non-point sources in watershed, septic systems, animal wastes and fertilizers from agricultural lands. Excess nutrients, nitrogen and phosphorus deteriorated the bay aquatic life were managed using Total Maximum Daily Loads (TMDLs) for nitrogen and phosphorus for the Indian River and its Bay and Rehoboth Bay in 1998 and the Little Assawoman Bay in 2004. According to Delaware Center for the Inland Bays Report [27] "to meet the load reductions required by the TMDLs, water quality goals include the elimination of all point sources if nutrient loading to the water bodies, along with a 40% reduction in


**Table 2.** Delaware farms, their acreages, and types of farming practices [25].

**Figure 3.** a. Yearly nitrogen loadings in the Delaware Inland Bays from non-point source pollution [14]. b. Yearly

These adverse environmental impacts have detrimental effects on overall habitat quality and put tremendous pressure on local aquatic habitats. As Delaware's coastal landscape continues to develop in a low-density and sprawling manner, the health of valuable natural resources, many of which sustain local economies, is increasingly at risk. Managing the demands for protecting critical habitat areas and managing water resources are complex and continuous

**Indian River Bay Rehoboth Bay Little Assawoman Bay**

Agriculture 44.6% 39.4% 33.0% 17.0% 54.7% 52.6% Boating < 0.1% < 0.1% < 0.1% < 0.1% < 0.1% < 0.1% Forest 11.0% 19.2% 7.4% 9.4% 6.7% 19.5% Point sources 12.5% 15.0% 27.3% 56.9% 0.0% 0.0% Rainfall 6.2% 8.6% 8.8% 6.9% 12.8% 11.5% Septic tanks 16.0% 9.3% 11.2% 3.8% 14.6% 5.6% Urban 9.8% 8.6% 11.7% 5.9% 11.2% 10.8%

**Table 1.** Relative contributions of nitrogen and phosphorus sources in the Inland Bays (Courtesy of [11]).

Nitrogen Phosphorus Nitrogen Phosphorus Nitrogen Phosphorus

phosphorus loadings in the Delaware Inland Bays from non-point source pollution [14].

challenges in Delaware [26].

Nutrient sources

38 Aquaculture - Plants and Invertebrates

nonpoint phosphorus loading in the Indian River Bay, Rehoboth Bay and Little Assawoman Bay, 65% reduction in the upper Indian River Watershed, a 40% reduction of nonpoint nitrogen loading in the Indian River Bay, Rehoboth Bay and Little Assawoman Bay, and an 85% reduction in the upper Indian River Watershed."

**Figure 4** provides promising results in regards to reductions in point source pollution with five-fold decrease in total nitrogen and phosphorus concentrations from 1990 to 2009 was recorded in Rehoboth and Inland River Bays. However, relative concentrations of nitrogen and phosphorus from agriculture increased up to 57% from its previous levels of 45% and 39% for nitrogen and phosphorus, respectively [13].

Anthropogenic activities not only degrade water quality but they also contribute to the reduction in biodiversity and abundance of coastal bay species [2]. Eutrophication, high turbidity, sedimentation, periodic hypoxic/anoxic conditions, annual fish kills, low species diversity, and physical disturbances due to anthropogenic activities all contribute to reduction in biodiversity and abundance [2, 27, 28]. **Figure 5** provides a description of land use in the Delaware Inland Bays Watershed from 1992 to 2007. Significant increases are apparent in developed areas and areas marked for development. In opposition, declines were observed in areas that were upland forests or small agricultural areas [13].

revitalization. According to Kellogg et al. [29], oyster reefs reduce eutrophication by enhanc-

Are Aquaculture Practices Sustaining Our Goal to Restore Oysters (*Crassostrea virginica*)?

http://dx.doi.org/10.5772/intechopen.78989

41

Shellfish aquaculture has become a new hope for the coastal community in Delaware, with the approval of new regulations allowing commercial shellfish aquaculture practices. The past 10 years leading up to these regulations, Delaware Inland Bays have been home to a small community-based oyster mitigation program, which biennially distributes oyster spat on shell to volunteer citizen growers. The use of cost-effective culture techniques to culture oysters for restoration has developed into an integral part of the ecological

Oyster gardening program was established to educate the public on the long-term stewardship and enhancement of the Inland Bays watershed as a collaborative effort with the leadership of the Center for the Inland Bays. The community oyster gardeners throughout the Inland Bays watershed support the program by caring for oysters held in floating cages 'Taylor floats' tied to their docks. Taylor floats are rectangular vinyl-coated 16 gauge, 25 mm wire mesh cages with a ring of PVC piping attached to the top to serve as the floatation gear (*see* **Figure 1b**). Each floating cage contains two square wire mesh baskets (46 x 46 x 23 cm) in

Spat on shell were provided during the initial 3 years of oyster gardening program and later a remote setting process was implemented to supply the oyster gardening volunteers spats on shells. Remote-setting of oyster (*Crassostrea virginica*) larvae from the Northeast-Haskins resistant strain (NEH) line is performed biennially in Delaware to supply small-scale oyster enhancement efforts. Oyster larvae are raised in the flow through tank from the pediveliger stage through metamorphosis and settled on cleaned disarticulated oyster shells (cultch). Shell bags containing 5–10 mm spat have been distributed to oyster gardeners throughout the Inland Bays. In the floating cages, gardeners are able to keep the spat clean and protected,

ing denitrification rates and assimilating nutrients into macrofauna.

**Figure 5.** Changes in land use in the Inland Bays watershed [13].

restoration efforts.

which the oysters are placed [24].

To enhance habitat quality, for the past 15 years oyster gardening program initiated and public engagement has been the major part of the program effort to have the coastal citizens to be stewards of those bays and contribute to restoration efforts in the Delaware Inland Bays. Those oysters are further stored in the bays as adults with the hope that they will thrive in the natural setting. The resulting larger, healthier oysters are used for restoration work in the area such as artificial reef creation and rip-rap planting, and contribute spat to enhance wild populations. Although there is a general consensus among scholars that the current rates of resource depletions and environmental degradation cannot be sustained over a long period of time, these floating gardens are important in their abilities to offer essential habitat

**Figure 4.** Nutrient loads reduction of point sources discharges in Rehoboth and Indian River Bay from 1990 to 2009 ([13]; www.inlandbays.org).

Are Aquaculture Practices Sustaining Our Goal to Restore Oysters (*Crassostrea virginica*)? http://dx.doi.org/10.5772/intechopen.78989 41

**Figure 5.** Changes in land use in the Inland Bays watershed [13].

**Figure 4.** Nutrient loads reduction of point sources discharges in Rehoboth and Indian River Bay from 1990 to 2009 ([13];

nonpoint phosphorus loading in the Indian River Bay, Rehoboth Bay and Little Assawoman Bay, 65% reduction in the upper Indian River Watershed, a 40% reduction of nonpoint nitrogen loading in the Indian River Bay, Rehoboth Bay and Little Assawoman Bay, and an 85%

**Figure 4** provides promising results in regards to reductions in point source pollution with five-fold decrease in total nitrogen and phosphorus concentrations from 1990 to 2009 was recorded in Rehoboth and Inland River Bays. However, relative concentrations of nitrogen and phosphorus from agriculture increased up to 57% from its previous levels of 45% and

Anthropogenic activities not only degrade water quality but they also contribute to the reduction in biodiversity and abundance of coastal bay species [2]. Eutrophication, high turbidity, sedimentation, periodic hypoxic/anoxic conditions, annual fish kills, low species diversity, and physical disturbances due to anthropogenic activities all contribute to reduction in biodiversity and abundance [2, 27, 28]. **Figure 5** provides a description of land use in the Delaware Inland Bays Watershed from 1992 to 2007. Significant increases are apparent in developed areas and areas marked for development. In opposition, declines were observed in areas that

To enhance habitat quality, for the past 15 years oyster gardening program initiated and public engagement has been the major part of the program effort to have the coastal citizens to be stewards of those bays and contribute to restoration efforts in the Delaware Inland Bays. Those oysters are further stored in the bays as adults with the hope that they will thrive in the natural setting. The resulting larger, healthier oysters are used for restoration work in the area such as artificial reef creation and rip-rap planting, and contribute spat to enhance wild populations. Although there is a general consensus among scholars that the current rates of resource depletions and environmental degradation cannot be sustained over a long period of time, these floating gardens are important in their abilities to offer essential habitat

reduction in the upper Indian River Watershed."

40 Aquaculture - Plants and Invertebrates

39% for nitrogen and phosphorus, respectively [13].

were upland forests or small agricultural areas [13].

www.inlandbays.org).

revitalization. According to Kellogg et al. [29], oyster reefs reduce eutrophication by enhancing denitrification rates and assimilating nutrients into macrofauna.

Shellfish aquaculture has become a new hope for the coastal community in Delaware, with the approval of new regulations allowing commercial shellfish aquaculture practices. The past 10 years leading up to these regulations, Delaware Inland Bays have been home to a small community-based oyster mitigation program, which biennially distributes oyster spat on shell to volunteer citizen growers. The use of cost-effective culture techniques to culture oysters for restoration has developed into an integral part of the ecological restoration efforts.

Oyster gardening program was established to educate the public on the long-term stewardship and enhancement of the Inland Bays watershed as a collaborative effort with the leadership of the Center for the Inland Bays. The community oyster gardeners throughout the Inland Bays watershed support the program by caring for oysters held in floating cages 'Taylor floats' tied to their docks. Taylor floats are rectangular vinyl-coated 16 gauge, 25 mm wire mesh cages with a ring of PVC piping attached to the top to serve as the floatation gear (*see* **Figure 1b**). Each floating cage contains two square wire mesh baskets (46 x 46 x 23 cm) in which the oysters are placed [24].

Spat on shell were provided during the initial 3 years of oyster gardening program and later a remote setting process was implemented to supply the oyster gardening volunteers spats on shells. Remote-setting of oyster (*Crassostrea virginica*) larvae from the Northeast-Haskins resistant strain (NEH) line is performed biennially in Delaware to supply small-scale oyster enhancement efforts. Oyster larvae are raised in the flow through tank from the pediveliger stage through metamorphosis and settled on cleaned disarticulated oyster shells (cultch). Shell bags containing 5–10 mm spat have been distributed to oyster gardeners throughout the Inland Bays. In the floating cages, gardeners are able to keep the spat clean and protected, greatly minimizing the negative impacts of predators. Since 2009, simple alterations in choices of shell containment gear were made to try to increase settling efficiency rate and spat set. Shell containment gears included common diamond plastic mesh bags, wire baskets, and plastic aquaculture trays. Setting efficiency was estimated and for small-scale growers, the stacked aquaculture trays had the highest set efficiency and proved advantageous for several reasons, including: reduced handling time, uniform shell distribution within tanks, and easyto-clean detritus between shell layers [84]. With improved growth and survivorship due to increased water flow, greater access to particulate foods, and much reduced risk of burial by sediments [9, 10], the resulting larger, healthier oysters have the potential to contribute spat for the enhancement of wild populations and are 'planted' in areas of the bays for local restoration work. Determining the remote set process success is often neglected, yet gathering this critical information will inform managers of the approximate number of spat distributed in smallscale programs and commercial scale aquaculture operation alike.

The creation of artificial reefs in designated areas is often used for oyster restoration, but the Delaware program started using riprap planting. Riprap is an irregular, large loose stones used to hinder the eroding effects of wave action. When oysters are planted in riprap, they are nestled in stable crevices between the rocks, mimicking the relatively secure, three-dimensional structure of naturally occurring oyster reefs that are integral to the oysters' survival [24]. Considering how limited oyster population in the Delaware Inland Bays, any effort to restore this keystone species in rip-rap crevices far closer than not making any effort and aquaculture is a step closer to a solution.

Although oyster aquaculture may be impacted by excess nutrients, it can also be a solution to mitigate this problem. According to Rose et al. [30], nitrogen removal by farmed shellfish was a more favorable solution per acre than BMPs for agricultural and storm-water runoff. Although new regulation allows oyster aquaculture in strategically identified areas in Delaware Inland Bays, Delaware is currently the only state on the Northeast Atlantic seaboard without commercial shellfish aquaculture. Legislation is developing policy and protocols for implementation, as the push for legalized aquaculture grows. Neighboring states have shown the economic and cultural benefits of functioning industry. Three Inland Bays in Southern Delaware, due to protection from open waters and ease of access for workers, offer promising future locations for bottom leases. Oysters are functionally extinct within the Bays and with the rapid development of the local watershed, the ecological services oysters contribute are more important than ever. Oyster aquaculture can help restore depleted wild populations of oysters while filtering the water, providing structural habitat, and creating a new sources of jobs. There is a unique opportunity to study directly how aquaculture facilitates restoration considering the impacts and benefits community driven oyster gardening program has provided since 2003. Delaware Department of Natural Resources and Environmental Control (DNREC), Delaware Division of Fish and Wildlife provides proposed shellfish regulations, proposed shellfish aquaculture development areas, legal notices and updates on regulations related information in their website at http://www.dnrec.delaware.gov/fw/fisheries/pages/ shellfishaquaculture.aspx.

**3. Subtropical estuary "Apalachicola Bay" characteristics and** 

Apalachicola Bay is a subtropical, barrier island estuary located along the northeast Gulf of Mexico in northwest Florida. The bay, a National Estuarine Research Reserve (ANERR), is a river-dominated system [33, 34] with a highly variable salinity regime. Its main source of freshwater, the Apalachicola River, the largest river in Florida with the highest riverine discharge rate [35, 36] is formed at the confluence of the Chattahoochee and Flint rivers, both with

**Figure 6.** Delaware Inland Bays. Shellfish growing waters ([31]; http://www.dnrec.delaware.gov/swc/wa/Pages/Shellfish-

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43

**challenges**

Growing-Waters.aspx).

**Figure 6** shows the shellfish growing areas in Delaware Inland Bays while **Figure 7** shows proposed shellfish aquaculture development areas in the Inland Bays.

Are Aquaculture Practices Sustaining Our Goal to Restore Oysters (*Crassostrea virginica*)? http://dx.doi.org/10.5772/intechopen.78989 43

greatly minimizing the negative impacts of predators. Since 2009, simple alterations in choices of shell containment gear were made to try to increase settling efficiency rate and spat set. Shell containment gears included common diamond plastic mesh bags, wire baskets, and plastic aquaculture trays. Setting efficiency was estimated and for small-scale growers, the stacked aquaculture trays had the highest set efficiency and proved advantageous for several reasons, including: reduced handling time, uniform shell distribution within tanks, and easyto-clean detritus between shell layers [84]. With improved growth and survivorship due to increased water flow, greater access to particulate foods, and much reduced risk of burial by sediments [9, 10], the resulting larger, healthier oysters have the potential to contribute spat for the enhancement of wild populations and are 'planted' in areas of the bays for local restoration work. Determining the remote set process success is often neglected, yet gathering this critical information will inform managers of the approximate number of spat distributed in small-

The creation of artificial reefs in designated areas is often used for oyster restoration, but the Delaware program started using riprap planting. Riprap is an irregular, large loose stones used to hinder the eroding effects of wave action. When oysters are planted in riprap, they are nestled in stable crevices between the rocks, mimicking the relatively secure, three-dimensional structure of naturally occurring oyster reefs that are integral to the oysters' survival [24]. Considering how limited oyster population in the Delaware Inland Bays, any effort to restore this keystone species in rip-rap crevices far closer than not making any effort and

Although oyster aquaculture may be impacted by excess nutrients, it can also be a solution to mitigate this problem. According to Rose et al. [30], nitrogen removal by farmed shellfish was a more favorable solution per acre than BMPs for agricultural and storm-water runoff. Although new regulation allows oyster aquaculture in strategically identified areas in Delaware Inland Bays, Delaware is currently the only state on the Northeast Atlantic seaboard without commercial shellfish aquaculture. Legislation is developing policy and protocols for implementation, as the push for legalized aquaculture grows. Neighboring states have shown the economic and cultural benefits of functioning industry. Three Inland Bays in Southern Delaware, due to protection from open waters and ease of access for workers, offer promising future locations for bottom leases. Oysters are functionally extinct within the Bays and with the rapid development of the local watershed, the ecological services oysters contribute are more important than ever. Oyster aquaculture can help restore depleted wild populations of oysters while filtering the water, providing structural habitat, and creating a new sources of jobs. There is a unique opportunity to study directly how aquaculture facilitates restoration considering the impacts and benefits community driven oyster gardening program has provided since 2003. Delaware Department of Natural Resources and Environmental Control (DNREC), Delaware Division of Fish and Wildlife provides proposed shellfish regulations, proposed shellfish aquaculture development areas, legal notices and updates on regulations related information in their website at http://www.dnrec.delaware.gov/fw/fisheries/pages/

**Figure 6** shows the shellfish growing areas in Delaware Inland Bays while **Figure 7** shows

proposed shellfish aquaculture development areas in the Inland Bays.

scale programs and commercial scale aquaculture operation alike.

aquaculture is a step closer to a solution.

42 Aquaculture - Plants and Invertebrates

shellfishaquaculture.aspx.

**Figure 6.** Delaware Inland Bays. Shellfish growing waters ([31]; http://www.dnrec.delaware.gov/swc/wa/Pages/Shellfish-Growing-Waters.aspx).
