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Penaeus vannamei inland farming: Perspectives and opinions

2022; Wiley; Volume: 15; Issue: 4 Linguagem: Inglês

10.1111/raq.12782

1753-5123

Otávio Augusto Lacerda Ferreira Pimentel, Luke A. Roy, Elizabeth Pereira dos Santos, Valdemir Queiroz de Oliveira, Luís Otávio Brito,

Aquatic life and conservation

Aquaculture is an activity that plays an important role in seafood global supply, food security, economic and social development.1 World aquaculture production continues to grow and in 2020 reached 122.6 million tonnes in live weight, an increase in 6.7 million tonnes to total production reported in 2018.2 In 2020, crustacean farming was the third largest aquaculture sector in terms of production (11.2 million tonnes) and the second in monetary value (USD 81.5 billion).2 The marine shrimp species Penaeus vannamei or Litopenaeus vannamei as a synonym,3 is the most widely cultured crustacean species with production in marine, estuarine and inland environments, totalling 5.8 million tonnes in 2020.2 This production volume is equivalent to 51.7% of world crustacean production.2 In the world, the main crustacean producing continents in inland regions are Asia (4.4 million tonnes), followed by Americas (72 thousand tonnes) and Europe (3.1 thousand tonnes).2 There is tremendous potential for culture of this species in inland regions far from the coast. In fact, in the last 20 years an increasing trend in P. vannamei production using brackish and freshwater has been observed, indicating a greater use of inland areas for the development of this activity (Figure 1). Marine shrimp culture is carried out in several countries, often at distances far from the coast,5, 6 using oligohaline (0.5–5.0 g L−1) and mesohaline water (5.0–18 g L−1),7 from well, artificial reservoirs, lakes and rivers. The use of these water sources for the culture of P. vannamei is practiced in countries such as China, Thailand, Vietnam, Ecuador, Mexico, United States, Brazil and other countries.7-14 Culture of P. vannamei is performed in a wide variety of environments which is possible due to the unique physiological characteristics of the species, particularly high adaptability to wide temperature and salinity gradients. P. vannamei can thrive in natural and culture environments with salinity between 0.5 and 60 g L−1 and temperature between 24 and 35°C.15-18 Despite the remarkable ability of this Penaeid shrimp to grow in a wide range of salinities, culture water must often be modified or amended to correct for ionic deficiencies in the culture medium. The need for ionic corrections occurs due to the variable characteristics of salinity and the ionic profile of water from rivers and wells (Table 1). This high variability is due to the geological characteristics that are reflected in the ionic composition of the water,11, 19 which most of the time is ionically unbalanced. As a strategy to enable marine shrimp culture in inland regions, Boyd9 indicated that brine obtained from salt production evaporators is one alternative whereby the ionic composition of culture water obtained from wells can be modified. In other cases, fertilizers containing specific ions that are deficient, such as potassium, calcium or magnesium, in the culture medium can be added to ameliorate suboptimal culture conditions.14 This ionic addition is often performed in order to create ionic conditions similar to seawater, adjusting calcium:magnesium:potassium (Ca:Mg:K) ratio to 1:3:1.19 There are other species of shrimp that are raised in inland regions. Notably, the Black Tiger Prawn, P. monodon, has been cultured in inland regions, particularly in India, albeit this species tolerance to lower salinities is not as robust as P. vannamei.23-26 Dozens of authors have confirmed the ability of P. vannamei to adapt to low salinity conditions, demonstrating remarkable results in terms of growth and survival.13, 14, 27-34 As a recent example, Pimentel et al.20 and de Oliveira et al.35 demonstrated that the dilution of seawater in freshwater (salinity ~2.5 g L−1) did not compromise the adaptation of post-larvae to these culture conditions and did not limit P. vannamei juvenile production at a high stocking density (2000 shrimp m−3). De Moura et al.36 found that the inclusion of 3% seawater in an intensive nursery (1000 shrimp m−3) provided acceptable survival (>90%), suggesting this strategy could be employed to mitigate the effects of ionic imbalance in low salinity water. Several reasons contributed to the shift of marine shrimp (Penaeus vannamei) production into inland regions in recent years. First, the ability of this species to be cultured in a wide variety of salinities and ionic profiles opens opportunities for commercial producers that have access to non-traditional culture mediums other than seawater. Real estate prices and values are always rising in coastal regions, making it difficult to secure property on which to build new farms. The difficulty in securing permits, due to stringent environmental laws in coastal and estuarine areas which are often protected sensitive ecosystems with multiple uses, has forced those seeking to invest in shrimp farms to look to inland regions to farm.9, 10, 14 Finally, the emergence of several pathogens in coastal regions has further encouraged the search for inland regions to develop shrimp farms.37 The search for regions further away from the coast for the implementation of shrimp farms isolates producers from the problems that exist in traditional marine coastal areas, thus increasing farm biosecurity and improving control over the spread of diseases.5, 9 In Thailand, the emergence of viral diseases, such as white spot syndrome and yellow head disease, forced producers to migrate to inland regions to distance themselves from contaminated coastal regions.38 Due to this displacement, the largest concentration of shrimp farms in Thailand is in the lower central plain, where there are a greater number of rice producers, and consequently, easy access to freshwater sources.39 China is an example of another Asian country where most of the shrimp (Penaeus vannamei) production comes from the use of freshwater (extremely low salinity water) in inland crops.5, 14 In this country, shrimp farming has migrated to inland regions due to diseases outbreaks and higher availability of farmable land in these regions than on the coast.40, 41 Subsequently, inland marine shrimp production growth in Asia represents approximately 98% of all crustacean world production in inland regions.2 In the United States, Penaeus vannamei shrimp production in inland regions, such as in the Texas, began in the 1970s and reached its peak between 2002 and 2003.42 Currently, commercial farms that produce marine shrimp in inland areas using earthen ponds are mainly located in the states of Alabama, Texas and Florida.9, 14, 43-46 In Alabama and Florida, water from saline wells is used for the marine shrimp culture. US shrimp production has been progressively falling in recent years due to the reduction in the price of imported shrimp relative to domestic product, increasing feed costs and increased operational costs.42, 45, 46 There are several farms in the US Midwest including states such as Kentucky, Indiana, Ohio, Iowa and others that have been producing shrimp in indoor systems, particularly zero exchange biofloc production systems.47, 48 These farms are very small in scale, supplying specific niche markets with shrimp and represent a small fraction of total US shrimp production compared to outdoor semi-intensive production systems.47 In these indoor biofloc systems, farmers typically use reconstituted seawater with a salinity around 15 g L−1. Hence, in order to supply unique market opportunities in inland regions, a production system is being used that is better suited for the climate of the northern US regions, which are much colder than the states in which semi-intensive outdoor earthen ponds are used in the South. In Brazil, in some regions of the states of Rio Grande do Norte, Ceará (Figure 2a), Paraíba (Figure 2b), Pernambuco, Sergipe and Alagoas, there is an increase in the number of Penaeus vannamei marine shrimp producers who use oligohaline and mesohaline water far from the sea, where traditionally aquaculture has been more prevalent.49 In the Pernambuco state, a marine shrimp farm that uses water from São Francisco River, which is one of the most important rivers in Brazil, mixed with well water, operates approximately 500 km far from the sea, in a region where fruit production is the main agricultural activity. The expansion and use of inland areas for shrimp culture in Brazil is largely due to lower land prices. In addition, the presence of rivers, reservoirs and aquifers with more than 350,000 wells, as registered in the Geological Service of Brazil, distributed throughout the country allows producers to take advantage of available aquatic resources.50 In excess of 83,000 of these wells have conductivity above 200 μS cm−1, and more than 63,900 are located in the Northeast region of the country,50 where climatic conditions are favourable for marine shrimp culture year-round. In Brazil, the use of well water, rivers and reservoirs, where the water is characterized as brackish (salinity greater than 0.5 g L−1 and less than 30 g L−1), cannot be used for human supply without prior conventional or advanced treatment [National Environment Council (CONAMA) Resolution n° 357/2005].51 In addition, due to the concentration of these salts, this water also becomes suboptimal for use in traditional agricultural activities, such as irrigation, since the constant use of this water can cause soil salinization, thus affecting plant development.52 As an example, regions producing rice, coconut, sugar cane and pasture in the state of Sergipe were transformed into shrimp producing units. This was heavily influenced by high productivity, profitability and, in the case of rice culture, easy pond construction.53 Hence, aquaculture is a viable alternative for the use of these water resources by not only producing a high nutritional value food source, but also increasing food security in these regions and providing a source of income for rural producers. In addition, the use of wastewater from desalinators54 and the use of areas with salinized soil, degraded by irrigated agriculture,55 for aquaculture can expand shrimp farming to inland regions. Faced with this expansion of inland shrimp farming, hatcheries initially bet on post-larvae adaptation to this new farming condition56 and currently on breeding programs for low salinity to meet growing demand.57 Complementary technologies to avoid soil salinization, limiting discharge of effluents into natural aquatic bodies and social strategies to work with traditional agriculture for dual use of available freshwater resources, have been suggested by some authors as an effective strategy for fostering the development of shrimp farming in inland regions.9, 14, 39, 58 In this way, alternatives can be used to reduce negative environmental impacts and optimize the production process, enabling the growth of inland aquaculture in an environmentally friendly way. Among the technologies that can be adopted to maximize production and minimize environmental impacts are the use of culture systems with minimal or no water exchange (with reuse) based on fertilization with organic carbon sources (e.g., molasses, sugar and fermented vegetable bran) and inorganic carbon as a fertilization strategy.20, 35, 36 These systems provide a reduction in the effluent emission frequency to the environment, as fertilization based on organic and inorganic carbon favours the nitrogen cycling to less toxic compounds such as nitrate, providing the adoption of higher stocking densities while increasing system biosecurity.59, 60 In addition, the use of these systems contributes to improving zootechnical indices (increased productivity and reduced feed conversion ratio), when compared to traditional culture systems, reducing the use of area and the risk of contamination or soil salinization, because culture units are fully lined.60-63 Farming systems in which recirculation and water reuse occur are both sustainable and environmentally friendly, as effluents from shrimp farming can be used for irrigation or be integrated to grow vegetables or fruits in conventional aquaponics or FLOCponics when using heterotrophic systems as biofloc technology.64-68 As an example, Mariscal-Lagarda et al.,69 by integrating tomato production with the culture of P. vannamei in low salinity water (0.65 g L−1), showed that 13.2% and 2.1% of the total nitrogen input into the system was converted to shrimp and tomato biomass, respectively. Likewise, 8.9% and 4.3% of total phosphorus supplied to the system was converted into shrimp and tomato biomass. Miranda et al.,70 irrigating a melon crop with effluents from a P. vannamei shrimp low salinity production system, showed that reuse of shrimp farm effluents did not change yield or quality of the melon crop when compared to traditional irrigation with river water. The authors concluded that the use of effluents from shrimp farming with low salinity could be a good alternative for crop irrigation, assuming the plants in question are tolerant of culture medium salinity. Also, effluents from the production of tilapia and shrimp using low salinity water are being used for fertigation of saltbush (Atriplex nummularia) to feed goats and sheep in the semiarid region of Brazil, 320 km from the coast.54 Furthermore, the use of marine shrimp effluents has been reported as a viable source of nutrients to produce microalgae and zooplankton.71-73 Another factor that should be considered is the use of the Internet of Things (IoT) in real-time monitoring of marine shrimp farming in inland areas.74 An example of this is the use of acoustic feeders, based on shrimp feeding activity.75 This technology can be applied seeking to improve management and increase the productivity of these systems. However, we must also consider the financial condition of producers, the geographical isolation of many inland shrimp farms and the difficulty in securing reliable access to the internet. These factors are very real barriers to the use of these newer production technologies. Thus, if circumstances are favourable for inland shrimp culture, in addition to using IoT technologies, water use efficiency can be increased by incorporation of culture and effluent management techniques for production in inland regions. Hence, a water resource that is suboptimal for traditional agriculture activities can be re-tasked by farmers for an important role in inland aquaculture shrimp production. Inland Penaeus vannamei marine shrimp production using various production systems including traditional earthen low salinity water pond systems, production systems with reduced water exchange and culture systems which incorporate water reuse and/or integration of production with vegetables, all can be considered viable alternative for sustainable aquaculture development in different regions of the world. Each production scenario will present different challenges since the environmental, logistical and economic conditions for those using inland low salinity water resources in different parts of the world are unique. Low salinity water sources used to produce shrimp in inland regions can be markedly different, and amendment of the water source is often necessary. Individual producers must reflect on their own situation and decide which production system best suits their needs. A collaborative effort between institutions of higher learning (e.g., universities and research institutes), state and federal governments, and members of private industry to support new and existing commercial aquaculture producers farming shrimp in inland regions is critical for sustaining and growing this industry in the future. Furthermore, we would like to suggest the development of research that can improve the productivity of inland P. vannamei farming systems in inland regions. Studies should be carried out to determine the minimum acceptable concentration of major ions, such as calcium, potassium and magnesium, in the water for the culture of marine shrimp in reduced salinity without compromising growth and survival. Finally, studies seeking to determine essential aqueous microelements for optimal growth and survival of marine shrimp cultured in inland low salinity regions are of paramount importance. Specifically, research that evaluates supplementation strategies for microelements (water versus feed) which would lead to optimized inland shrimp production would be valuable to commercial producers. The role of microelements in inland low salinity shrimp production is an area of research that to date has received very little attention by researchers. Otávio Augusto Lacerda Ferreira Pimentel: Conceptualization; investigation; visualization; writing – original draft. Luke Aaron Roy: Investigation; visualization; writing – review and editing. Elizabeth Pereira dos Santos: Investigation; visualization; writing – review and editing. Valdemir Queiroz de Oliveira: Investigation; visualization; writing – review and editing. Luis Otavio Brito: Supervision; investigation; visualization; writing – review and editing. Otávio Augusto L. F. Pimentel and Elizabeth P. dos Santos are grateful for the scholarships granted by the Coordination for the Improvement of Higher Education Personnel (CAPES; process numbers: 88887.612993/2021-00 and 88882.436231/2019-01). Luis Otavio Brito is grateful for the grant provided by the National Council for Scientific and Technological Development (CNPq; process number: 309669/2021-9). The authors have no conflict of interest to declare. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.