Water Quality and Plankton Dynamics in Litopenaeus vannamei Pond Culture Systems

Shrimp aquaculture has become one of the fastest-growing food production sectors worldwide, with Litopenaeus vannamei dominating global cultivation due to its high adaptability and economic value (Tacon et al., 2020). Intensive pond systems are widely applied to meet production demands, yet these systems are inherently unstable because water quality is strongly influenced by biological activity, organic loading, and microbial proliferation (Emerenciano et al., 2017; Paez-Osuna, 2001). Fluctuations in physicochemical parameters, particularly pH and dissolved oxygen, are common in shrimp ponds and often linked to the metabolic activity of plankton communities and decomposition of organic matter (Liu et al., 2018; Wasielesky et al., 2013).

Pond ecosystems supporting shrimp culture function as semi-closed environments where nutrient accumulation and microbial processes continuously reshape water conditions (Avnimelech, 1999; Burford et al., 2003). These ecological shifts may influence not only water stability but also the abundance of opportunistic pathogens such as Vibrio spp., which are widely recognized as major threats to shrimp health and survival (De Schryver and Vadstein, 2014; Xiong, 2018). Therefore, understanding the temporal dynamics of water quality and biological indicators is essential for sustainable shrimp farming.

Despite extensive research on shrimp production, many studies primarily focus on growth performance and feeding efficiency rather than the ecological processes occurring within ponds (Samocha et al., 2004; Ray et al., 2010). Investigations addressing plankton succession and microbial dynamics often rely on experimental or short-term datasets, which may not fully represent real farming conditions (Hu et al., 2015; Zhang et al., 2016). Moreover, routine farm monitoring data, although abundant, are rarely utilized as scientific evidence to describe ecological patterns in operational shrimp ponds (Krummenauer et al., 2014; Anh et al., 2010).

This gap limits the understanding of how water quality and biological communities fluctuate naturally during shrimp culture cycles under commercial management. Continuous pond monitoring provides valuable insight into ecosystem behavior, including plankton dominance shifts, diel pH variation, oxygen depletion, and microbial proliferation (Lin and Chen, 2001; Lancelot and Mathot, 1987). Such information is crucial to anticipate environmental instability and disease risk in intensive shrimp culture systems.

This study was conducted to provide a descriptive ecological assessment of pond water quality, plankton dynamics, and microbial indicators in Litopenaeus vannamei culture systems using field-based monitoring data collected during shrimp production cycle phases. The research aims to highlight how physicochemical fluctuations are linked to biological processes within shrimp ponds and to provide practical insights for improving environmental management in pond-based aquaculture.

Despite the widespread application of water quality monitoring in shrimp aquaculture, many studies rely on snapshot measurements that do not adequately capture temporal ecological dynamics throughout the production cycle. In intensive Litopenaeus vannamei pond systems, limited attention has been given to the combined temporal behavior of physicochemical parameters, microbial indicators, and plankton community structure as an integrated ecological unit. As a result, the understanding of how pond ecosystems evolve during culture progression remains incomplete. This study addresses this gap by systematically monitoring temporal changes in water quality, bacterial and Vibrio abundance, and plankton composition across consecutive culture phases. The objective is to provide an ecological perspective that supports adaptive management and environmental stability in intensive shrimp pond systems.

This study employed a longitudinal monitoring approach to capture temporal ecological dynamics in intensive Litopenaeus vannamei pond culture systems. Observations were conducted across consecutive production phases in multiple pond units to ensure representativeness of routine farming conditions. Monitoring focused on key physicochemical parameters, microbial indicators, and plankton communities that are widely recognized as indicators of pond ecological status. This approach allows for the identification of temporal patterns and interactions among water quality, microbial load, and plankton dynamics during the culture period.

The study was conducted in a commercial-scale pond aquaculture facility culturing Litopenaeus vannamei under semi-intensive management. Earthen ponds were operated using similar preparation and water management protocols throughout consecutive production cycle phases. Pond ecosystems in shrimp farming are recognized as dynamic aquatic agro-systems strongly influenced by organic loading, plankton productivity, and microbial processes (Boyd and Tucker, 2012; Edwards, 2015).

pH was measured twice daily (morning and afternoon) using a portable digital pH meter to capture diel fluctuations associated with photosynthesis and respiration in shrimp ponds (Boyd and Tucker, 2012; Zhang et al., 2019). Dissolved oxygen (DO) was measured in the early morning using a calibrated DO meter, as minimum oxygen levels typically occur before sunrise due to plankton and microbial respiration (Edwards, 2015). Water transparency was monitored using a Secchi disk to indicate plankton density and suspended solids (Boyd and Tucker, 2012).

Water samples were collected aseptically and analyzed for total Vibrio abundance using standard microbiological plating techniques on selective media. Vibrio populations are widely used as indicators of microbial imbalance and disease risk in shrimp ponds (Primavera et al., 2018; Nguyen et al., 2022). Elevated Vibrio loads are often associated with high organic matter and unstable environmental conditions (Zhang et al., 2019; Edwards, 2015).

Water samples were collected from each pond and examined microscopically to identify dominant phytoplankton groups. Plankton composition serves as a biological indicator of nutrient dynamics and ecological condition in shrimp ponds (Boyd and Tucker, 2012). Shifts between green algae and blue-green algae were recorded to evaluate trophic changes and bloom dynamics (Edwards, 2015).

Monitoring data were compiled descriptively to evaluate ecological trends across production cycle phases. Observational analysis was applied to interpret fluctuations in physicochemical, microbial, and plankton indicators without experimental manipulation, a method widely used in pond ecosystem studies (Primavera et al., 2018).

The results illustrate that water quality and biological components in shrimp ponds exhibit clear temporal variability rather than remaining stable throughout the culture period. Changes in physicochemical parameters were closely followed by shifts in microbial abundance and plankton composition, indicating strong ecological coupling within the pond system.

Water quality dynamics in pond-based culture systems of Litopenaeus vannamei exhibited clear temporal fluctuations across the observed production cycle phases, reflecting the highly dynamic nature of shrimp pond ecosystems. Variations in physicochemical

parameters such as pH and dissolved oxygen (DO), together with changes in microbial abundance and plankton composition, indicated ongoing ecological shifts throughout the culture period (Table 1). Such variability is typical in semi-intensive and intensive shrimp ponds, where nutrient loading and biological processes continuously alter water conditions (Boyd and Tucker, 2012; Edwards, 2015).

The pH values recorded during the culture period showed daily and cyclical variation between morning and afternoon measurements (Figure 1). This pattern is strongly associated with photosynthetic activity and respiration of phytoplankton communities in the ponds. Higher afternoon pH levels observed in several pond units suggest active phytoplankton photosynthesis, which consumes carbon dioxide and increases alkalinity during daylight hours. Similar pH

Table 1: Summary of physicochemical water quality parameters (pH and DO) in Litopenaeus vannamei ponds

oscillations have been widely reported in shrimp ponds and are considered key indicators of plankton productivity and metabolic balance (Boyd and Tucker, 2012; Zhang et al., 2019).

Dissolved oxygen levels also displayed notable fluctuations, particularly between early morning and daytime observations (Figure 2). Morning DO reductions in some sampling periods indicate oxygen depletion caused by nighttime respiratioen of plankton and microbial communities, a common phenomenon in ponds with high organic matter accumulation. Conversely, increased DO during daytime corresponds to phytoplankton photosynthesis, which enhances oxygen availability. These dynamics highlight the strong coupling between biological activity and oxygen balance in shrimp culture ponds (Araujo et al., 2025).

Microbial monitoring revealed variability in total Vibrio abundance across ponds and production cycle phases (Table 2). Elevated Vibrio counts during certain periods are commonly associated with increased organic matter, feed residues, and unstable

Table 2: Distribution of Vibrio counts observed during shrimp culture cycles.

water quality, which create favorable conditions for opportunistic bacteria. The observed Vibrio dynamics align with previous studies indicating that microbial populations in shrimp ponds are closely linked to environmental parameters and nutrient enrichment (Primavera et al., 2018; Nguyen et al., 2022). These fluctuations emphasize the importance of continuous microbial surveillance in intensive Litopenaeus vannamei farming to prevent disease outbreaks.

Plankton composition varied markedly throughout the culture period, with shifts in dominant phytoplankton groups reflecting changing nutrient conditions and pond trophic status (Table 3). The occurrence of green algae and blue-green algae indicates nutrient-rich environments typical of shrimp ponds receiving regular feed inputs. While moderate phytoplankton presence supports natural food availability and oxygen production, excessive blooms may destabilize water quality and increase bacterial proliferation (Edwards, 2015). Therefore, plankton dynamics serve as both ecological indicators and management signals in pond-based shrimp culture.

Table 3: Distribution of dominant plankton groups observed during shrimp culture cycles.

Overall, the combined physicochemical, microbial, and plankton data demonstrate that shrimp ponds function as complex and fluctuating agro-aquatic ecosystems. Variability in water quality across production cycle phases is not merely incidental but reflects biological feedback processes inherent to L. vannamei pond farming. These findings reinforce that maintaining pond stability requires continuous monitoring and adaptive management to balance nutrient input, plankton growth, and microbial load (Hasan and New, 2013; Costa-Pierce et al., 2019).

The monitoring data demonstrated that pond ecosystems used for the culture of Litopenaeus vannamei experienced continuous and interconnected fluctuations in physicochemical and biological parameters throughout the production cycle phases. Variations in pH and dissolved oxygen reflected the metabolic activities of plankton communities and the accumulation of organic matter typical of shrimp ponds. Shifts in plankton composition and periodic increases in Vibrio abundance indicated that ecological instability can emerge even under routine pond management. These findings confirm that water quality dynamics are closely linked to biological processes within shrimp ponds and highlight the importance of integrated ecological monitoring to maintain a balanced culture environment. Based on these observations, it is recommended that shrimp pond management incorporate routine assessment of both physicochemical and microbial indicators to anticipate ecological shifts that may compromise pond stability. Early detection of plankton blooms and elevated Vibrio levels should be used as practical warning signals for implementing corrective measures such as aeration adjustment, water exchange, and organic load control. Furthermore, standardized documentation of water quality and biological monitoring across production cycle phases is essential to support adaptive management and improve sustainability in pond-based Litopenaeus vannamei aquaculture systems. These findings emphasize that routine and continuous ecological monitoring is a key requirement for adaptive management in intensive shrimp aquaculture, enabling early detection of unfavorable environmental trends and supporting sustainable production performance.

The authors gratefully acknowledge the support provided by the Postgraduate school University of Brawijaya, for facilitating this research.

This study provides a temporally integrated ecological assessment of intensive Litopenaeus vannamei pond systems by simultaneously tracking physicochemical dynamics, microbial indicators (including Vibrio abundance), and plankton community shifts across consecutive production phases. Unlike previous studies that often evaluate these components in isolation or at single time points, this research captures their synchronized temporal variability within operational ponds. The findings offer novel insights into how short-term ecological fluctuations reflect underlying nutrient dynamics and organic matter accumulation, strengthening the ecological basis for adaptive water quality management in intensive shrimp aquaculture systems.

Aryani Rahmawati: Performing the research, formal analysis of the data, wrote the original manuscript draft.

Asep Awaludin Prihanto: Led the conceptualization of the research, contributed to the methodology, reviewing and editing the manuscript,reviewed the final manuscript for publication.

Moh. Khusaini: Academic supervision, assisted in data handling and interpretation.

Anthon Efani: Contributed to the formal analysis of the data, and reviewed the final manuscript.

The authors declare that no generative AI and AI assisted technology was used in the creation of this manuscript.

The authors have declared no conflict of interest.