World Aquaculture - December 2023

60 DECEMBER 2023 • WORLD AQUACULTURE • WWW.WAS.ORG techniques, the ability to reproduce after six months of age and a typical life span of up to two years (Lovatelli and Sarkis 2011). In addition, this species primarily inhabits sandy substrates at depths from 10 meters to 120 meters. Favorable conditions for these mollusks include water temperatures that are less than 28o C. Although Nodipecten nodosus is native to the Caribbean region, particularly within the USVI, warmer temperatures and lack of scallop fishing activity (which typically uses dredges), could possibly explain the lack of wild scallops in the Caribbean islands. The integration of scallop aquaculture into the island’s economy would be beneficial, because utilizing the available environmental resources can boost employment, income, and exports. Other positive impacts of mariculture involve ecosystem filtration, habitat abundance, and prevention of coastal erosion. In addition, mariculture has potential to reduce the demand for land-based resources. Among the challenges for culturing this species include its sensitivity to high temperatures (>28o C), biofouling, and predation (Freites and Núñez 2001, Rupp and Parsons 2004, Velasco and Barros 2019). A first step in evaluating the potential of scallop aquaculture was conducted by performing a quantitative data analysis of seawater surface temperatures in the USVI using data provided by VI Department of Planning and Natural Resources (DPNR) from various studies conducted from 2010 to 2021. Monthly average water temperatures for each island (St. Croix, St. Thomas, and St. John) from 2010 through 2021 were subsequently calculated (Figure 1). Beginning in May, average monthly surface water temperatures for all islands began to exceed the baseline temperature of 28o C for the lion’s paw scallop, and remained above 28o C through November. Average temperatures from May through November ranged from 28o C to 30o C, before slowly declining in December. Rupp and Parsons (2004) indicated that the median lethal temperature (LT50) for N. nodosus at a salinity of 33 ppt, after 96 hours of exposure was 28.0o C for adults, 29.4o C for juveniles, and 30.3o C for spat. Hence, Molluscan aquaculture in the Caribbean has been the subject of extensive research efforts since the late 1960’s, with evaluation of some native species including mangrove oysters (Crassostrea rizhophorae), American oysters (C. virginica), Atlantic pearl oyster (Pinctada imbricata), South American rock mussel (Perna perna), nucleus scallop (Argopecten nucleus), lion’s paw scallop (Nodipecten nodosus), zigzag scallop (Euvola ziczac), calico scallop (Argopecten gibbus), and queen conch (Strombus gigas), among others (Jory and Iversen 1985, Sarkis et al. 2001, Lovatelli and Sarkis 2010, Rupp and Parsons 2016, Velasco and Barros 2019, DonesOrtiz et al. 2022). Regarding molluscan mariculture, the shelf regions of many islands within the Caribbean are too tiny to sustain extra fishing effort, and while certain areas may be able to support more exploitation, increasing seafood output must come from resources that have not yet been exploited. On a positive note, mollusk culture has the potential to improve seafood output and close the gap between supply and demand in several islands. Economically, it stimulates financial flow, which would help to reduce significant trade imbalances while also providing much-needed jobs. However, no commercial-scale scallop cultivation projects currently exist within the Caribbean. Unfortunately, as Creswell et al. (2001) pointed out, the lack of infrastructure, technical knowledge, financial expenditures, and other valuable resources are acknowledged as factors in the minimal growth of the aquaculture sector in the Caribbean region. An evaluation of the potential implementation of scallop aquaculture within the United States Virgin Islands (USVI), to enhance food security and the economy of the Islands, was conducted recently. One of the target species is the lion’s paw scallop (Nodipecten nodosus). Its range extends from North Carolina in the U.S. to Brazil. Desirable characteristics of this species include fast growth rate, reaching up to 18 centimeters in length. N. nodosus also has a high market value, well known culture Potential of scallop aquaculture in the U. S. Virgin Islands (USVI) Destinee Turnbull, Gerson Martinez and Herbert Quintero FIGURE 1. Monthly average seawater temperature values in the U.S. Virgin Islands, St. Croix (STX), St. Thomas (STT), and St. John (STJ). Establishing a regional shellfish hatchery that may support the culture of native/ endemic species has been signaled as a priority for more than a decade, and could be a strategy to integrate mariculture into the Caribbean islands’ economy. This could in turn help generate employment, revenue, and exports by utilizing the resources provided by the environment, as well as improve communities’ resiliency.