Globally, declines in freshwater biodiversity have been recognized to be far greater than those in marine or terrestrial realms. And like the rest of tropical Asia, the Philippine freshwater ecosystems and their biodiversity have been neglected. Our goals in this review are to provide indications where further research is needed, what systems are underrepresented and which organisms have been neglected. In this study, we determined the current knowledge on freshwater ecosystems in the country through critical evaluation of available peer-reviewed literature. A structured search on studies on Philippine freshwater systems published from January 1988 to December 2012 was performed using the Thomson Reuter’s Web of Science and Zoological Records. A total of 281 papers that have directly assessed Philippine freshwater systems and/or have actually collected and examined aquatic organisms from these systems were included in the review. More than 70% of the papers were produced solely by local researchers or with international collaborators. There was a significant steady increase in Philippine freshwater studies, with systematics (105 papers) and freshwater fish (78 papers) being the most frequently studied research area and organism, respectively. Rivers (116 studies) and lakes (112 studies) are still the most frequently studied freshwater systems. Among the papers reviewed, Luzon freshwater systems were the focus of most studies with Laguna de Bay being the most researched. Freshwater systems in the Visayas and Mindanao received little research attention. Finally, we presented a four-point research agenda, the results of which could form the basis for policy or management decisions to aid future conservation and sustainable management of freshwater ecosystems and their biodiversity in the Philippines.

Keywords: freshwater biodiversity, biomonitoring, biotic index, climate change, protected areas

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The study of freshwater ecosystems in the country has long had the reputation of being fragmentary and inconsistent, especially when compared to its marine counterparts. Other scientists have in fact noted that many studies that have been conducted on Philippine freshwaters have not gone beyond the “age of exploration”, which resulted to it being poorly represented in the scientific literature. This scenario has been consistent for both lotic and lentic habitats, even for those considered as major river and lake ecosystems, including those found in key biodiversity or known protected areas. This has gone on for decades in spite of the obvious need for invigorated and scientifically-driven approaches to study and manage freshwater ecosystems throughout the country, especially since freshwater ecosystems, including its flora and fauna, are under increasing threat from both natural and man-made environmental stressors, including intensive aquaculture, leading to eutrophication, the introduction of non-native species, as well as climate change. This is further aggravated by the low number of experts in various fields of basic and applied freshwater biology including taxonomists, limnologists, restoration ecologists etc. to deal with various problems and challenges in the Philippine setting. This paper presents the background, history and origins of freshwater biology research in the Philippines and the contributions of the University of Santo Tomas from 2002 to present.

Keywords: Wallacea Expedition, Tropical Lakes, History of Science, Freshwater Zooplankton, Invasive Species, Limnology

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Cerberus is a genus of semi-aquatic snakes that inhabit a wide range of aquatic habitats including estuarine environments. There are two species belonging to this genus known to occur in the Philippines. However, its distributional record is still not well established since only limited areas are surveyed despite of its wide distributional range in the coastal habitats of the country. This study primarily aims to document the occurrence of Cerberus in Iyam River, Lucena City. The scalation patterns and metric characters were also described to determine the range of individual variability among the species. Samples were collected from different habitat types in the sampling area by systematic transect walking. By close examination, it was revealed that the samples exhibit the established morphological description of Cerberus schneiderii. Moreover, population exhibit high variability in scalation pattern such as anal plate, anterior chin shield, lower labials at the first chin shield, type of scale, prefrontal plate, upper labials at loreal, and ocular ring; and metric characters such as total length, tail length, snout-vent length (SVL) and Tail:SVL ratio (H’ = 0.67-1.0). Statistical analysis further showed a strong significant correlation (P = <0.01) between total length and SVL, total length and weight, SVL and weight, and total length and tail length. The occurrence of different morphotypes is very important in understanding the extent of intra-specific variation within Cerberus schneiderii and the possible role of local adaptations and habitat use.

Keywords: morphotype, scalation, dog-faced water snake, individual variability

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The importance of fish parasite research is now only gaining traction not only from biodiversity scientists, but also to ecologists and local policy makers as well. Fish parasites are ecologically important for they are good indicators of ecosystem integrity. In this study, fish endo-parasites of various littoral fish species in Lake Taal were identified and the status of endo-parasitism of the lake was evaluated by providing factors on host-parasite interaction such as feeding habits and host body size, which affect the prevalence of parasites, and their mean intensity. With the unique ecosystem of Lake Taal, it calls for further research especially about biodiversity assessments. Fish specimens were collected and subjected to parasitological examination by extracting their gut, immersing them to 0.9% saline solution, and examining them for the presence of endo-parasites. The samples were taken using beach seine trawling near coastal areas with the aid of the local fishermen. A total of 711 fish specimens were collected from the months of July, August, and September 2015. From these, parasites were seen from 11 fish specimens belonging to 5 different species (Channa striata, Glossogobius giuris, Parachromis managuensis, Toxotes jaculatrix, and Zenarchopterus sp.). Three parasite genera were identified, namely Opegaster sp. (Platyhelminthes: Opecoelidae), Camallanus sp. (Nematoda: Camallanidae), and Andracantha sp. (Acanthocephala: Polymorphidae). From these three parasites spanning three different phyla, Andracantha sp. is the first report of its genera from Philippine fish, providing a contribution to the present Philippine parasite biodiversity listing. The quantitative measurements of parasite burden correlated with the factors aforementioned showed the low endo-parasitism within the lake.

Keywords: Endo-Parasites, Taal Lake, Littoral fishes

In the Philippines, the taxonomy of freshwater zooplankton fauna from ground waters remain poorly understood, yet knowledge on this group is important to know patterns in groundwater biodiversity to develop sound conservation policies. In this study, zooplankton were studied by collecting samples from selected groundwater-dependent ecosystems in Bulacan Province. Results indicate the presence of 13 species belonging to 10 families from Rotifera, Cladocera, and Copepoda. Large portion of the samples included the copepods Mesocyclops and Thermocyclops spp together with cladocerans Ceriodaphnia cornuta and Moinodaphnia macleayi. Observation of these taxa in groundwater-dependent ecosystems suggests high surface and sub-surface hydrological connectivity in the Province. Lastly, new locality record of Elaphoidella bidens in the Philippines was establishes.

Key words: Caves, Cladocera, Copepoda, groundwater pumps, springs, and wells

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The Taal Volcano Protected Landscape (TVPL) encompasses a prehistoric volcano caldera that caters to many documented endemic species. Although regarded as a unique area with the potential to house a diverse ecological community, biodiversity research in TVPL is still found wanting. The present paper aims to provide baseline information and increase research interests on the herpetofaunal diversity of TVPL, in light of its many undocumented terrestrial faunal species. Twelve study sites within the municipalities of Tanauan, Mataasnakahoy, and Balete were visited during survey trips from May to November 2015. A combination of transect and opportunistic sampling techniques were utilized, with morphometric data and sexual maturity recorded for each specimen collected. This preliminary survey provided 24 newly documented species of amphibians and reptiles occurring within TVPL. A total 10 frog species (from families Bufonidae, Ceratobatrachidae, Microhylidae, Dicroglossidae, Ranidae, and Rhacophoridae) and 14 reptile species (from families Agamidae, Gekkonidae, Scincidae, Varanidae, Acrochordidae, Colubridae, Elapidae, and Tryonychidae) were documented. Of the reptiles recorded, 3 are endemic species and widespread throughout the Philippines: Gekko mindorensis, Hydrosaurus pustulatus, and Draco spilopterus. Also recorded were the Philippine endemic frogs Kaloula picta and Limnonectes woodworthi along with the Luzon endemics Platymantis mimulus and Varanus marmoratus. The species-effort curve of amphibians showed a distinct plateau whereas the species-effort curve of reptiles has shown an increasing trend suggesting that additional sampling efforts should be done in the area to further increase knowledge of the TVPL herpetofaunal diversity.

With the exponential rise of human activities in the past decades, majority of studies conducted in Taal Volcano Protected Landscape (TVPL) are geared towards the conservation and preservation of Lake Taal’s remaining biodiversity. However, the current structure and assemblage of its terrestrial biotic communities remain relatively unstudied. In this study, we conducted biodiversity censuses in the four sites in TVPL to provide baseline information regarding the community structure of the selected study sites. Comparison of the plant diversity in Taal Volcano Crater Island and Romandan Falls within the forested areas of Mataas na Kahoy, Batangas reveal that both sites support remarkably different vegetation, with the former supporting a smaller floral diversity. The fairly small number of animal samples present difficulty in providing conclusive findings to the wildlife structure of the two study sites. However, the presence of 11 animal species exhibit valuable results in determining the ecological status of TVPL. It is deduced that several ecological barriers exist between the sites, which is attributed to their unique terrestrial biota.

Keywords: Philippines; Ecology; Biogeography

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The study of physico-chemical parameters in fish ponds in Candaba, Pampanga was conducted to determine the quality of water for fish pond from July to August, 2014. Water samples were tested in-situ using probe meter: Thermo Orion Model A920. The results showed variation in the observed parameters at the different sampling stations and two sampling dates. Temperature ranged from 29±16.74 to 35.23±1.01˚C. pH values were 8.70±5.02 to 9.57±1.11. Dissolved oxygen values were 5.20±3 to 7.57±0.77mg/l. Electrical conductivity ranged from 220±0.01 to 489±0.57µS/cm. The values for temperature and DO were higher than accepted values for fish culture while those of other parameters favored for good fish production. The observations in this study suggest that fish production in some fish ponds of Candaba, Pampanga could be practiced without adverse effects posed by the quality of water.

Keywords: Physico-chemical parameters, fish pond, freshwater, desirable limit

Benthic macroinvertebrates were sampled by a D-Frame Dip net (450 µm mesh size) from 3 sites of a stream contaminated with acid mine drainage from a gold mine in Loei Province, Thailand. Sialis larvae (Insecta: Megaloptera: Sialidae) were dominant taxa (49%) in the high Arsenic upstream site 1 followed by dipteran larvae (26%), gastropods (15%) and Coleoptera (10%). The less contaminated, downstream site 3 was dominated by Coleoptera (32%), Ephemeroptera nymphs (24%) and Caridina (F. Atyidae, O. Decapoda-20%). Seventeen percent of mouthpart deformity of chironomid larvae was also found in site 2. It is preliminary concluded that the extent of contamination with mining waste water has affected both, taxon composition and the proportion of chironomids with deformed mouth parts.

Keywords: gold mine, Arsenic, stream benthos, mouthpart deformity, chironomids

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