Laguna de Bay: Institutional development and change for lake basin management

Santos-Borja, Adelina C.; Nepomuceno, Dolora N.

doi:10.1111/j.1440-1770.2006.00310.x

Cited by 20 publications

(14 citation statements)

References 1 publication

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“…Organised attempts to mitigate detrimental environmental impacts of aquaculture on the lakes date to the establishment of the LLDA in the mid-1990s and were strengthened further through the implementation of the Clean Water Act (2004). The Clean Water Act has similar aims to the European Water Framework Directive in that it seeks to both protect and restore pristine and human-disturbed waterbodies (DENR-EMB, 2014;Santos-Borja, 1997;Santos-Borja & Nepomuceno, 2006;Zafaralla, Santos, Orozco, & Elegado, 2002). Seasonal patterns were determined from monthly values, averaged over the period 1901-2016 (Figure 2a,b).…”

Section: Study Areamentioning

confidence: 99%

Potential anthropogenic regime shifts in three freshwater lakes in Tropical East Asia

et al. 2019

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Regime shifts in ecology are characterised by major, often abrupt changes in ecosystem structure and functioning in response to one or more driving variables, or pressures. Changes in the provision of ecosystem services are a potential outcome. Despite the current combination of rapidly increasing pressures on what are often highly important socio‐ecological systems, the resilience of lakes in the warm tropics to human perturbation is far less well understood than those at higher latitudes. This paper focuses on evidence of aquatic ecosystem change from a cluster of three deep, freshwater, volcanic crater lakes (Yambo, Mohicap, and Sampaloc) at low altitude on the island of Luzon, Philippines. The lakes support different intensities of aquaculture, an important livelihood but also a driver of poor water quality throughout tropical Asia. Measured and monitored climate and water quality data, in addition to sedimentary evidence from sediment cores collected from the three study lakes, were used to determine the magnitude and trajectory of changes in lake water quality. Sediment cores were radiometrically dated and analysed for organic matter, spheroidal carbonaceous particles, and diatom remains. Diatom data were zoned numerically using cluster analysis. Diatom remains were also used to infer past variations in pH and possible relationships between potential driving climatic variables (temperature and rainfall). Diatom data sets were explored using detrended component analysis and principle component analysis. Despite differences in intensity of aquaculture, a common trajectory and timing of a potential regime shift, characterised by a replacement of benthic with planktonic diatoms and an increase in diatom accumulation rates from the early to mid‐1980s, is evident, and attests a low threshold for disturbance effects. A predominantly planktonic diatom flora has persisted even after recent improvements in environmental quality. The potential new regime may be less resilient and more susceptible to harmful algal blooms, abrupt expansions of anoxic conditions, and periodic mass fish kills when compared with its former state. The research further highlights the sensitivity of freshwater ecosystems in the warm tropics to disturbance pressures, and the risks to livelihoods, ecosystem services, and sustainable development.

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Section: Study Areamentioning

confidence: 99%

Potential anthropogenic regime shifts in three freshwater lakes in Tropical East Asia

et al. 2019

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“…The main causes of water pollution of Laguna Lake are surface sources such as domestic wastewater and inorganic materials from industrial activity [9]. The hydrological behavior of the lake and the groundwater and surface water in the water catchment area needs to be investigated and monitored continuously to deal with the various problems related to the above-mentioned human activities.…”

mentioning

confidence: 99%

Identification of Waters Incorporated in Laguna Lake, Republic of the Philippines, Based on Oxygen and Hydrogen Isotopic Ratios

Maruyama¹,

Kato

2017

Water

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Abstract:We examined the oxygen and hydrogen isotopic ratios of surface waters and groundwaters in the catchment of Laguna Lake, Republic of the Philippines, to identify the types of water that combine and control these ratios in the lake water. The oxygen and hydrogen isotopic ratios of water samples collected from rivers, lakes, springs, and irrigation canals were determined using cavity ring-down spectroscopy. The lake water data deviated from the meteoric line of the Philippines by between −13.5‰ and −10‰, and between −11.5‰ and −1.5‰ in the dry and wet seasons, respectively. The values for the groundwaters and surface waters were mainly between −8‰ and 3‰ throughout the year. In addition to rainwater, evaporative concentration, which may have an almost constant effect throughout the year, was the main control on the oxygen and hydrogen isotopic properties of Laguna Lake. The contributions of the surface waters and groundwaters to the oxygen and hydrogen isotopic ratios of the lake were relatively constant. Based on their isotopic properties, the waters within the water catchment area of Laguna Lake can be roughly divided into lake water with heavier isotopic ratios, and groundwater and surface water with lighter isotopic ratios.

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“…Overexploitation and unsustainable aquaculture practices have contributed to a marked decline in water quality, biodiversity, and productivity (Zafaralla et al . ; Santos‐Borja and Nepomuceno ). Laguna de Bay has also been categorised as a critically endangered lake, despite being part of a candidate key biodiversity area (CKBA).…”

Section: Aquaculture and Water Qualitymentioning

confidence: 99%

Establishing the impacts of freshwater aquaculture in tropical Asia: the potential role of palaeolimnology

Legaspi

Lau

Jordan

et al. 2015

Geography and Environment

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Freshwater aquaculture is an important source of protein worldwide. Over-exploitation of fisheries can, however, add severely to pressures on ecosystem functioning and services. In Southeast Asia, aquaculture in freshwater lakes contributes significantly to the economy and to reductions in poverty and nutritional insecurity. However, overstocking and excessive feeding of fish can lead to a degradation of affected water bodies, manifest as eutrophication, toxic algal blooms, losses of biodiversity and amenity, anoxia and, in extreme cases, collapse of fisheries. Projected increased warming and storminess associated with global climate change are likely to magnify existing problems. Matching levels of aquaculture production with ecological carrying capacity is therefore likely to become increasingly challenging, requiring levels of data and understanding that are rarely available, a problem that is impossible to rectify in the short term using standard limnological approaches. This paper reviews the development of freshwater aquaculture in the Philippines, associated environmental impacts, and relevant environmental regulations and regulatory bodies. The potential role of palaeolimnology, a science that is relatively under-utilised in the tropics generally and in tropical Asia in particular, in complementing extant datasets, including monitoring records, is highlighted through reference to a preliminary study at Lake Mohicap. Lake Mohicap currently supports aquaculture and is one of a cluster of seven volcanic crater lakes on Luzon, the largest of the archipelago of islands forming the Philippines.

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Laguna de Bay: Institutional development and change for lake basin management

Cited by 20 publications

References 1 publication

Potential anthropogenic regime shifts in three freshwater lakes in Tropical East Asia

Potential anthropogenic regime shifts in three freshwater lakes in Tropical East Asia

Identification of Waters Incorporated in Laguna Lake, Republic of the Philippines, Based on Oxygen and Hydrogen Isotopic Ratios

Establishing the impacts of freshwater aquaculture in tropical Asia: the potential role of palaeolimnology

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