22 MARCH 2026 • WORLD AQUACULTURE • WWW.WAS.ORG opportunistically across trophic levels, and serve as essential links in coastal food webs (Quinitio and Parado-Estepa, 2003). However, these crustacean populations are increasingly imperiled by a convergence of anthropogenic pressures. Climate variability and pollution, particularly from illegal aquaculture expansion, sewage discharge, and agricultural runoff, are pushing these species to the brink. Shrimp and crabs are especially sensitive to temperature and salinity fluctuations. While elevated temperatures can boost their metabolism and immune responses, sudden salinity changes, often caused by tidal blockage or flooding, can compromise osmoregulation and exacerbate stress (Robinson, 2010; Millard et al., 2021). Such instability weakens their physiological defenses, leaving them susceptible to a host of diseases. Pollution in the SPCW adds another lethal dimension. Heavy metals such as cadmium, lead, and mercury leach into estuarine waters from agricultural and industrial activities, accumulating in the tissues of shrimp and crabs. Research has shown that Scylla paramamosain exposed to cadmium suffer oxidative stress, hepatopancreatic tissue damage, and gut microbiota imbalances, significantly reducing survival and growth rates (Cheng et al., 2023). In parallel, Penaeus species exposed to microplastics and persistent organic pollutants (POPs) exhibit impaired digestion, immune suppression, and altered enzyme function which often results in reduced market value and reproductive failure (Mahari et al., 2024; Camacho-Jiménez et al., 2023). These findings mirror broader trends in Southeast Asia (SEAFDEC, 2000; Pati et al., 2023). More alarming, however, has been the surge in disease outbreaks directly linked to degraded water quality and poor pond management. White Spot Disease (WSD), caused by White Spot Syndrome Virus (WSSV), remains a devastating threat to shrimp farms, rapidly decimating stocks during periods of high organic load and fluctuating salinities (Cheng et al., 2020). Acute Hepatopancreatic Necrosis Disease (AHPND), driven by Vibrio parahaemolyticus, thrives in nutrient-rich, poorly managed environments, leading to massive tissue necrosis and early mortality in shrimp (De Silva et al., 2021; Anson, 2023). For mud crabs, Rust Spot Disease (RSD) and Shell Disease Syndrome, both linked to sediment contamination, have become increasingly common, causing lesions and weakening the exoskeleton, often beyond recovery (Carella, 2022; Arulmoorthy et al., 2020). Even more insidious are conditions like Black Gill Disease, a chronic affliction that hampers respiratory function in both shrimp and crabs. This disease often arises in aquaculture environments burdened with suspended solids and decaying organic matter (Khuong, 2016; Ranjan, 2017). Likewise, the highly contagious Taura Syndrome Virus (TSV), which causes red tails and soft shells in Penaeus vannamei, spreads rapidly in overcrowded, polluted ponds, leading to widespread losses (De Silva et al., 2021; Ranjan, 2017). The stress of chemical exposure is not merely acute, as it extends to long-term reproductive consequences. In Macrophthalmus japonicus, a burrowing mud crab species, toxicant exposure disrupts gene expression tied to molting and gamete development, sharply reducing reproductive output (Park et al., 2019). The silent assault of endocrine-disrupting chemicals on crustaceans in polluted estuarine zones cannot be overlooked. Studies dating back to the late 1990s revealed that such chemicals inhibit molting and limb regeneration, critical processes for growth and escape from predators in crabs (Fingerman et al., 1998). In modern contexts, these findings remain starkly relevant. Today, pesticides and industrial compounds continue to wash into the SPCW’s interconnected estuarine corridors, further weakening the region’s crustacean base (Figure 12). In severe cases, pond crashes during pathogen outbreaks, often triggered by poor water quality or habitat degradation, can result in the total loss of stock, dramatically reducing production and profit margins (Mahari et al., 2024). As such, the resilience and profitability of aquaculture in the SPCW are closely tied to the ecological health of mangrove habitats and estuarine water quality. Restoring Mangrove Integrity to Safeguard Crustacean Populations Crustaceans such as Scylla serrata (mud crab), Portunus pelagicus (blue swimming crab), and various Penaeus species thrive in the nutrient-rich estuarine corridors of the SPCW, where mangrove forests form the backbone of their life cycles. Yet, years of unregulated fishing, mangrove degradation, and habitat conversion have severely weakened these natural sanctuaries. Conservation efforts must start where life begins for these species: in the mangroves. FIGURE 11. A fisherman’s child proudly holding a freshly caught Scylla spp. mud crab. Photo credit: H.N. Gasmen. FIGURE 12. Coastal households discharge untreated waste directly into the waters of the Sasmuan Pampanga Coastal Wetlands. Photo credit: H.N. Gasmen.
RkJQdWJsaXNoZXIy MjExNDY=