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Unsustainable urbanization in the Indo-Pacific continues to threaten terrestrial and aquatic ecosystems due to habitat disturbances driven by human pressures. The Marikina Watershed, one of the most critical watersheds in the Philippines, has been exposed to economic and population growth resulting in landscape modification and water quality degradation. This led to establishment of the Upper Marikina River Basin Protected Landscape (UMRBPL) to rehabilitate the watershed ecosystem. To strengthen this conservation initiative, we aimed to assess whether the establishment of UMRBPL has been effective in conservation of benthic macroinvertebrate diversity in streams of the Marikina Watershed. Sixteen streams, eight from UMRBPL and eight from adjoining unprotected areas, were monitored for benthic macroinvertebrate assemblages and their habitat environments, such as pH, water temperature, dissolved oxygen, total dissolved solids, conductivity, salinity, and canopy openness. Principal component analysis and non-metric multidimensional scaling based on the environmental variables and biological metrics, respectively, revealed that habitat quality and benthic macroinvertebrate assemblages significantly differed between the protected and unprotected streams, with the former having better environment and higher biodiversity. More precisely, protected streams have significantly higher dissolved oxygen and lower canopy openness and material loadings as compared to unprotected streams. Consequently, taxon richness was four-fold higher in protected streams while stream quality indices based on abundance of key invertebrate groups (EPTand EPTC) were ten-fold higher in protected streams, as compared to unprotected streams. This study demonstrates that freshwater protected areas play crucial roles in the conservation of stream ecosystems and biodiversity under rapid urbanization in developing countries, like the Philippines. Keywords: Philippines, biomonitoring, freshwater protected area, watershed governance, tropical streams, Aichi Target 11, Urbanization in the Indo-Pacific imposes significant demands on aquatic environments in terms of water resource uses (Cocklin and Keen 2000). As a result, urban systems continue to threaten stream biodiversity [...]

Lake Taal is one of the most significant lake ecosystems in tropical East Asia. In 2011, a review paper consolidated all known biodiversity and limno-ecological studies conducted in Lake Taal from the beginning of the 20th century all the way to the late 2000s. It highlighted that insufficient funding, inadequate long-term monitoring data, and the publication culture of that time impeded having a comprehensive understanding of the lake. Since then, much research work has been done in Lake Taal, especially during the past decade. This review paper provides an analysis and summary of the research work conducted in Lake Taal over the past 10 years. The recent decade has seen a steady increase in scientific interest in Lake Taal made evident by more scientists and institutions working on topics involving the lake. Research grants, collaborations, and publications have also significantly increased during the past 10 years. This has led to an improved understanding of the lake's biodiversity, ecology, and impacts of intensive aquaculture and the introduction of non-native species. Taken together, this paper presents a better understanding of Lake Taal, which can be utilized for the design and improvement of conservation, preservation, and management programs for this multi-use freshwater system. [ABSTRACT FROM AUTHOR]

One hundred eighty-three individuals of Glossogobius aureus, native to Lake Taal, Philippines, were collected in 2021–2022. Of these, 4 endohelminths were found and identified: Andracantha gravida (Acanthocephala: Polymorphidae), Schyzocotyle acheilognathi (Platyhelminthes: Bothriocephalidae), Azygia sp. (Platyhelminthes: Azygiidae), and Opegaster minima (Platyhelminthes: Opecoelidae). These helminths represent new host records for G. aureus and provide novel contributions to the recent Philippine parasite biodiversity listing. Among these 4 helminths, Azygia sp. was the most prevalent, had the highest percent dominance and mean intensity, and had a broader range followed by S. acheilognathi, A. gravida, and O. minima, respectively. These findings highlight the need to further explore Lake Taal's parasitofauna, especially with regard to the invasion of S. acheilognathi, and the transmission specificity of O. minima, which can be utilized as a keystone parasite biomarker and in return aid in the management and conservation efforts in Lake Taal. [ABSTRACT FROM AUTHOR]

In developing countries such as the Philippines, the inadequacy of even the most basic limnological datasets available has hindered planning and implementation of science-based management policies for inland waters. This situation is aggravated by overutilization of natural resources for ecosystem services such as water usage, aquaculture, fishing, and tourism. We reviewed published researches related to the Seven Maar Lakes (SMLs) in Luzon Is., Philippines to summarize information invaluable for the protection and sustainable use of these resources. Popular scientific search engines were utilized to gather peer-reviewed research articles and reports from both private institutions and government agencies. Literature and timeline from the 1930s to 2019 was classified into topics – namely socioeconomics, fisheries, biodiversity, and environment. Based on the literature survey, a variety of challenges, knowledge gaps, and promising research directions were identified, which are essential to the sustainable ecosystem management of the SMLs. Aquaculture practices impacting the lakes and its underestimated biodiversity were described. Measured vertical profiles of dissolved oxygen (DO), temperature, conductivity, pH, and salinity was supplemented by our preliminary limnological survey in the SMLs. Past and present monitoring data of selected physicochemical parameters were assessed from which the changing limnological status of the lakes was determined. We recommended measures motivated by strategic environmental assessments while still considering maintained economic yields. A sustained collaborative effort from different sectors is strongly suggested not only to manage the SMLs but also to address trade-offs among critical ecosystem services. Aside from the need for well-designed, long-term water quality monitoring, we also stress the synergistic interpretation of all available knowledge, which can contribute to the resolution of environmental issues at both local and global scales. [ABSTRACT FROM AUTHOR]

In this paper, we aimed to contribute to the conservation research of a heavily impacted tropical lake ecosystem by characterizing its previously undescribed fish diversity and also elucidating the trophic structure of its fish community. Our study area is Lake Sampaloc, a small crater lake in the southern region of Luzon Island, Philippines. This lake has been heavily used for economic resource functions, such as aquaculture, for decades. Hindrances to the effective implementation of regulatory provisions have produced detrimental ecological effects on the lake, which has recently been declared as "Threatened Lake of the Year 2014". We employed several sporadic fish surveys during a span of two years (2012 to 2014) to identify fishes in the lake. We also used stable isotope analysis to elucidate the trophic level and production reliance of important aquatic consumers. We discovered that the lake fish populations are heavily reliant on periphyton production and are mostly composed of non-native and potentially established invasive fish species. In addition, trophic niche overlaps are observed among non-native fish and native species. For the past three decades, Lake Sampaloc has been classified as eutrophic with high phytoplankton standing biomass. A possible direction for lake rehabilitation research is to investigate ways to change the present turbid state into a clear water system that is predominantly composed of submerged native vegetation. Such a macrophyte-based environment may help sustain the development and recruitment of native juvenile fish and also provide a more diverse functional habitat for fish assemblages that have overlapping trophic niches. [ABSTRACT FROM AUTHOR]

Macrophytes play an important role in the aquatic ecosystem since they are good bioindicators and serve as habitat for littoral fishes. This research involves the use of the hydroacoustic method aided by visual observation and quantification in determining the distribution and abundance of submerged macrophytes in the littoral zones of Lake Taal. The results were used to generate spatial distribution and percent cover maps of macrophytes in the lake. Based on the surveys, five macrophyte species were present in Lake Taal. Denser macrophyte beds were concentrated in the south basin of the lake. High nutrient levels in the south basin contributed to heavy macrophyte growth in this area, which usually come from run-offs from the residential, commercial and agricultural watersheds. The lesser biomass of macrophytes in the north basin was attributed to clearing activities due to the construction of fish cages for aquaculture. Furthermore, we were able to observe that there were different dominant species in the north and south basins of the lake; Najas indica was more prominent in the north basin, while Vallisneria nanawas more common in the south. This study shows that anthropogenic sources of excess nutrients and other activities such as aquaculture play a role in altering the distribution of macrophytes in Lake Taal and how these can have potential detrimental impacts to the littoral zones of the lake. [ABSTRACT FROM AUTHOR]

Body size and environmental prey availability are both key factors determining feeding habits of gape-limited fish predators. However, our understanding of their interactive or relative effects is still limited. In this study, we performed quantitative dietary analysis of different body sizes of goby (Gymnogobius isaza) specimens collected from Lake Biwa between 1962 and 2004. First, we report that the diet was composed mainly of zooplankton (cladocerans and copepods) before the 1980s, and thereafter, shifted to zoobenthos (gammarids). This foraging shift coincided with, and thus can be linked to, known historical events in the lake at that time: decrease in zooplankton abundance with the alleviation of eutrophication, increase in fish body size resulting from fish population collapse, and increase in gammarid abundance due to reduced fish predation pressure. Supporting this view, our data analyses revealed how the long-term changes in the diet composition would be co-mediated by changes in fish body size and environmental prey availability. Specifically, while zoobenthos abundance strongly affected the fish diet composition, larger (smaller) fish preferred zoobenthos (zooplankton). Furthermore, the body size effects were stronger than those of prey availability. These results provide the best long-term evidence that fish feeding habits vary over decades with its body size and prey community due to anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Lotic ecosystems in urban areas are severely impacted by anthropogenic environmental stressors, such as deforestation and nutrient pollution, due to socioeconomic activities in the catchment. To work out measures for identification and mitigation of concurrent multiple stressors to a stream system, it is necessary to assess the relative importance of impacts by the individual stressors. Here we aimed to discriminate the covarying effects of nutrient pollution and deforestation on benthic macroinvertebrate communities in an urbanised tropical stream system. In the Silang-Santa Rosa Subwatershed (SSRS) of Laguna de Bay, benthic macroinvertebrates and physicochemical environments were investigated at 13 sites varying in human population density, riparian canopy, and land-use pattern as indicated by geographic information systems in the catchment. Regression and multivariate analyses were performed to identify the drivers of the biodiversity loss and understand its underlying mechanisms. In the SSRS, where rapid economic growth took place without updating poorly installed wastewater treatment plants (WWTPs), domestic activity indicated by human population density in the catchment was the primary factor in generating heavy phosphorous loadings (mean total phosphorus = 0.91; range = 0–1.50 mg/l) that caused hypoxia (mean dissolved oxygen = 2.98; range = 0.13–6.27 mg/l) in stream waters and subsequently reduced macroinvertebrate diversity (mean H' = 0.91; SD ± 0.61). Nutrient and organic pollution and riparian deforestation explained 53.5% and 9.7% of the variation of benthic macroinvertebrate communities in SSRS, respectively. Given such scenario, additional WWTPs servicing urban developments and improved riparian canopy cover in the SSRS can be both strategic and cost-effective in the initial steps of environmental mitigation in urbanised streams, especially in rapidly developing countries. [ABSTRACT FROM AUTHOR]

• Trichinella IgG antibody was detected in swine with very low positive cases in Bulacan, Philippines. • Important risks were outdoor housing management, pigs with unknown origin and fed with waste, and pig farms presence with rodents. • Results call a wider screening and isolation of Trichinella spp. in pigs from other Philippine provinces. Trichinella spp. is considered as one of the most widespread food-borne zoonotic parasites globally. The disease it causes impacts human public health, pig production, and food safety. Unfortunately in the Philippines, there is still insufficient research on the presence of Trichinella among livestock. This study aims to update its status and records in the country, by verifying the presence of Trichinella spp. IgG antibodies from the selected province, Bulacan, and link its potential presence to known animal husbandry and farm practices. This study was conducted in purposively selected slaughterhouses. Pigs were randomly selected for each slaughterhouse. Blood samples were collected and serum samples were harvested from each pig samples (n = 555). Sera were tested using ELISA for the detection of Trichinella spp. IgG antibodies. For serologically positive pigs, farm-based exposure assessment was conducted to evaluate potential routes of infection. For this study, a total of 555 blood sera, wherein three blood sera were detected to be serologically positive (low prevalence of 0.54 %, 95 % CI = 0.11–1.57). Potential infection routes point towards outdoor housing management, pigs with unknown origin, pig farms presence with rodents, and pigs fed with waste as important risks. In summary, the present paper confirms that Trichinella spp. antibodies were detected in very low prevalence in Bulacan, Philippines and demonstrated the potential utilization of antibody detection as an efficient and complementary early screening tool in Trichinella detection among pigs without immediately sacrificing livestock for the sake of testing. These results merit calls for a wider screening, testing, and isolation of Trichinella spp. in pigs from other Philippine provinces. [ABSTRACT FROM AUTHOR]