This set of guidelines has been developed to help national regulators and stakeholders on managing the diverse use of chemicals in aquaculture. It recognising the existing variation in capacity among AMS but has been designed so that it could be adopted and implemented within the specific policy and legal framework of each country. This document aims to provide guidance for Competent Authorities (CAs) in standards setting / regulating the use of Chemicals in Aquaculture and Measures to Eliminate the Use of Harmful Chemical among AMS. AMS are encouraged to assess and review gaps at their national level with regard to chemicals used in aquaculture, as listed in this document. Furthermore, it would also help to develop measures to eliminate the use of harmful chemicals in aquaculture; and it is further envisaged that a harmonised regional set of guidelines for the use of chemicals in aquaculture for ASEAN could be produced. The purpose of this set of guidelines is to list the major chemicals and other substances commonly used in AMS. This set of guidelines will also list the banned chemicals that should not be used or practiced by farmers or aquaculturist in all AMS. The list was compiled and agreed from previous workshops to assess and review gaps exist among AMS with regards to chemical use in aquaculture.

Food safety is one of the major concerns of products derived from aquaculture. Farm inputs, e.g. drugs and agrochemicals, introduced whether intentionally or unintentionally during culture, may contaminate and remain in the product and become a hazard to the consumers. Chemical hazards in aquaculture products, among them drugs used for the chemotherapy of bacterial infection in fish and other cultured aquatic animals present a negative impact in aquaculture. Fish farmers often result to this treatment in order to save their cultured stock when threatened with infection, although a general conception nowadays is the discouragement of its use, being considered only as the “last recourse.” Drugs, specifically antibiotics, have a long history of successful use in aquaculture (Alderman, 1980).

Lake Buhi (Fig. 1) is found in Buhi, Camarines Sur. It is situated at the north-eastern part of Iriga City. The lake has an area of 18 km2 and has an average depth of 8 m. The lake lies in the valley formed by two ancient volcanoes, Mt. Asog and Mt. Malinao. It was formed in 1641 when an earthquake caused a side of Mt. Asog to collapse. The resulting landslide created a natural dam that blocked the flow of nearby streams. Another theory suggests that it was formed by the eruption of Mt. Asog, which is now dormant. The lake is the home of the world s smallest fish, sinarapan (Mistichthys luzonensis). Aside from sinarapan, it also home for other native freshwater fishes such as 'irin-irin' (Redigobius dispar), 'dalag' (Channa striata), 'puyo' (Anabas studines), 'kotnag' (Hemiramphus sp.), 'burirawan' (Strophidon sathete), and native catfish (Clarias sp.). Today, the lake is one of the major aquaculture areas in the Bicol Region where commercial production of Nile tilapia (Oreochromis niloticus) and Mozambique tilapia (Oreochromis mossambicus) is done. The lake supplies the fish demand in the province. But the cyclical occurrence of fish kills threaten the aquaculture industry in the lake. On October 31, 2010, a massive fish kill was again experienced that resulted to almost 75% loss of the lake s fish stocks. The incident calls for inter-agency planning and consultations to address the cause of fish kill and save Lake Buhi from further deterioration. One of the major solutions that arised was the implementation of the ten percent area utilization for aquaculture activity as prescribed in R.A 8550, also known as the Philippine Fisheries Code of 1998. Thus, on March 24, 2011, navigational lanes, buffer zones, fish sanctuaries and reserves, and fishcage belts in Buhi Lake were delineatedupon the request of Mayor Rey P. Lacoste of Buhi.

The Laguna Lake Development Authority (LLDA) pioneered the implementation of Clean Development Mechanism (CDM) activities through the Laguna de Bay Community Carbon Finance Project or Carbonshed Project. This mechanism is embodied in Article 12 of the Kyoto Protocol wherein developing and developed countries can work together in reducing the emission of greenhouse gases (GHG) in the atmosphere. In the process, Carbon Credits (Fig. 1) are produced which the developed countries can use to offset their GHG emission. Likewise, the reduction of GHG emission in the lake s watershed improves environmental quality in the Laguna de Bay basin. The Carbonshed Project was implemented from 2004 to 2008 through a grant of USD 358,450 from the Japan Climate Change Initiative that the World Bank administers. The Project s main activity was the development of a set of small-scale projects that reduce GHG emissions in the watershed. Sub-projects were identified and selected through the Laguna de Bay Environmental Action Planning (LEAP) process, a participative and multi-stakeholder planning process that include the LGUs, River Councils and communities in a particular municipality or sub-watershed. The LEAP process was developed under another World Bank and Dutch Governmentfunded project, the Laguna de Bay Institutional Strengthening and Community Participation Project or LISCOP that was implemented almost as the same time as the Carbonshed Project. The small-scale CDM sub-projects (Fig. 2) are being implemented by local government units (LGUs) with technical support from the LLDA and funding support under the LISCOP project. The first bundle under the Methane Avoidance Category consists of seven LGU sub-projects on Materials Recovery Facility with Composting. A significant milestone, both for the LLDA and for the participating LGUs was reached on March 16, 2008 with the registration of the Laguna de Bay Community Waste Management Project: Avoidance of Methane Production from Biomass Decay through Composting-1 to the United Nations Framework Convention on Climate Change- Clean Development Mechanism Executive Board (UNFCCC-CDMEB). The estimated Carbon Emission Reduction was 6,058 tons CO2-e. The buyers of Carbon Emission Reduction (CER), which translates into Carbon Credits is the Community Development Carbon Fund (CDCF). An Emission Reduction Purchase Agreement (ERPA) was signed on June 30, 2006 between the LLDA, representing the CDM-project participants and the World Bank, representing the CDCF. A sub-ERPA was then signed between the LLDA and the project participants as a commitment to meet the obligations under the ERPA. The Carbonshed Project has also established a mechanism to ensure that the money from the carbon credits will be used for operational costs of the existing composting facilities or for new environmental and social investments in the localities implementing these projects.

Lake Mainit in Northeastern Mindanao is an important shared resource of the Provinces of Agusan del Norte and Surigao del Norte. It is distinguished as the deepest (219.35 m) and the fourth largest (17,060 ha) lake in the Philippines with 28 river tributaries and only one outlet river that flows into Butuan Bay. The most recent assessment in 2007-2008 showed that at least 15 species of aquatic plants, 41 species of fish, five crustaceans, and 10 mollusks occur in Lake Mainit and its outlet Kalinawan River. Lake Mainit has a very diverse fish community classified into three different groups, namely, true freshwater fishes (lake and riverine), amphidromous fishes, and catadromous fishes. This highly productive and diverse wetland ecosystem supports a thriving freshwater fishery and the livelihood of more than 3,000 fishers using a highly diverse fishing gear technology. The municipality of Kitcharao, Agusan del Norte has the largest contribution to fisheries production (Fig. 1). Environmental and human factors have threatened the biodiversity and productivity of the Lake in recent decades. Certain species of fish are feared to have been extinct; at least 13 of 37 species reported by Pauly et al. (1990) were no longer encountered in the present study. More than 65% of the fish are migratory between the lake and Butuan Bay through the Kalinawan River. The population of the once abundant giant mottled eel (Anguilla marmorata) has drastically declined, resulting from massive fishing on adult eels during their seasonal spawning along Kalinawan River. The native white goby (Glossogobius giuris), locally known as pijanga, remains the most important fishery resource in Lake Mainit (Fig. 2), but the current fish catch is about 63% of the 1997-98 production as reported by Galicia and Lopez (2000). Many species are caught in progressively smaller sizes, resulting in lower economic value and hence, marginal fisher incomes. Pollution, unsustainable fishing practices, high fishing pressure, and lack of enforcement of fisheries policies have drastically reduced the annual fish catch from 15,108 t in 1980-81 to only about 831.50 t in 2007-08, which is only about 5.5% of the production level 26 years ago. Lake Mainit experiences the typical syndrome of a threatened fisheries resources: biodiversity loss, high fishing pressure, use of unsustainable fishing gears and methods, declining fish catch and catch-per-unit-effort, decreasing size of fish caught, and marginal or meager fisher incomes barely enough to provide for the basic daily needs like food, health, and children s education. The Lake Mainit Development Alliance (LMDA), an inter-LGU alliance among the eight municipalities around the lake, provides a ray of hope for this threatened resource. A fisheries management program is being integrated into the Lake Mainit Development Agenda to help restore Lake Mainit fisheries resources to sustainable levels.

A study was done from June 2008 to June 2010 to compare the limnological features of two lakes in Laguna Province, namely, Sampaloc, a maar lake of San Pablo City, and Crocodile of Los Baños. Temporal variations were analyzed with emphasis on trophic state parameters monitored at three and two stations, respectively; and with three replicate areas/station. Statistical analysis used was the Kruskall-Wallis ANOVA and Pearson correlation analysis. Both lakes had significant to very highly significant seasonal differences in terms of water temperature (WT), total hardness (TH), nitrite-N, total inorganic nitrogen (TIN), soluble reactive phosphorus (SRP), total P (TP), and chemical oxygen demand (COD). Wet season (WS) lake warming in Lake Sampaloc possibly resulted from advective and convective heat transfers. In Lake Crocodile, solar heating is suspected because of cooling in January and warming in summer. In the dry season (DS), all ionic N forms and TIN spiked, implying improved N storage while oxidative N conversion improved and accompanied by enhanced algal growth. In Lake Crocodile, the WS saw increasing TH and NO2-N. In both lakes, elevated SRP and TP in DS was possibly caused by increased evaporation rates as P-augmenting human activities continued translating in increased pollution as evidenced by rising COD and Chl a. Chl a correlated with SDT, TA, EC, NO3-N, TIN, SRP and TP. The data is summarized in Table 1. Chl a ranges and overall means put Lake Sampaloc under eutrophic category, while Lake Crocodile is under mesotrophic to low-eutrophic. Species richness was higher in Lake Sampaloc with a cool month spike, the Cyanophyceae and Chlorophyceae exhibiting balanced representation. The Shanon-Wiener index of diversity, H range was 0.16-1.87. and the top three dominant species were Microcystis, Aulacoseira and Aphanocapsa. Lake Crocodile was mesotrophic to low-eutrophic with species richness spike in June and February, respectively. There were four to nine species found per station per sampling; the Shannon-Wiener H range is 0.07-0.96; and Microcystis, Coelastrum and Chroococcus disperses as dominants. Figure 1 shows the diversity indices for phytoplankton in the two lakes.

The seven lakes of San Pablo City are among the 20 small monogenetic volcanoes found at the Macolod Corridor of the Southwestern Luzon Volcanic Field. This study evaluated the relationship of sulfate distribution and provenance in sediments to the volcanic geology and origin of the lakes. Rock and sediment mineralogy indicated the absence of sulfursulfate bearing minerals. This is supported by the very low sulfate values in rocks from previous analyses. The elevated sulfate values (Fig. 1) previously noted in sediments, however, are not related to volcanism but are attributed to anthropogenic sources. Considered possible sources of sulfate are sewage, fertilizers, algicides, and fungicides.

Sardinella tawilis (Clupeiformes: Clupeidae) is the world s only freshwater sardine and is endemic to Taal Lake, Batangas, Philippines. Locally referred to as tawilis, it is the most dominant and commercially important fishery of the lake, but in recent years severe depletion has been apparent in catch records. A proposed management strategy favors the demarcation of a new fish sanctuary; however, it is unclear which area in the lake is appropriate for conservation. This study applied molecular genetics tools to describe the phylogeographic pattern of tawilis across Taal Lake to determine whether a single or multiple stocks exist; and which location supports the highest level of haplotype diversity to assist in the placement of the fish sanctuary. One hundred and forty-one specimens were collected from eight fishing locations around Taal Lake. Fish were indentified, the DNA extracted using a Chelex-resin method, amplified for the ribosomal 16S and mtDNA Cyt B gene regions, and sequenced. Sequences were cleaned using the genetics software Sequencher v4.8 (GeneCode Corp.), aligned and phylogenetic trees visualized in MEGA v5 (Tamura et al., 2007), and assessed for haplotype composition by location using DnaSP v5.1 (Librado and Rozas, 2009). Results for the haplotype frequency analysis showed two dominant haplotypes to be common at most or all fishing locations, with northern basin locations of the lake supporting a higher mean and absolute number of haplotypes than locations in the southern basin. Yet no fishing ground contained more than 45% of the total observed haplotype diversity and thus no ideal location for a new fish reserve could be identified. Rather, all specimens formed a single clade with no significant divergence between individuals from the eight fishing grounds for both genetic markers (Fig. 1). This suggests that all tawilis within Taal Lake are part of a single, panmictic stock. Given the mixing population, we suggest that a closed season be considered as an alternative strategy in managing the world s only freshwater sardine fishery.

Lakes Bito, Mahagnao, and Danao are renowned lakes in Leyte (Fig. 1). Lake Bito has an area of 126 ha and is within the jurisdiction of the town of MacArthur. It is the most exploited lake among the three study sites. About 40 percent of the lake is covered with fish pens and fish cages devoted to the culture of Nile tilapia. The deeper waters covering about 60% of the lake is devoted to open water fishery. Lakes Mahagnao and Danao are both located within declared natural parks. Lake Mahagnao, in Burauen, Leyte covers an area of 15.75 ha (Francisco, et al., 2001). The whole lake area is devoted to open water fishery, aside from being a source of the micro-hydroelectric power that provides electricity to Barangays Lugsungan, Cansiboy, and Mahagnao. Lake Danao in Ormoc City covers an area of 148 ha. The lake supplies water to the cities of Ormoc and Tacloban. The lake is also developed for tourism, with activities like boating, swimming, and hook and line fishing. There is very limited information about these lakes, with prior studies conducted by Montemayor (1985) and Francisco, et al. (2001). The data obtained was part of a preliminary study on the biodiversity of aquatic flora and fauna of these three lakes. The study was conducted in a period of one year to come up with baseline information about the three lakes. Sampling was conducted once a month in each of the three lakes. Depth, percent transparency, pH level, temperature, and dissolved oxygen (DO) were monitored through a longitudinal survey. Depth was measured using a depth gauge, transparency was monitored using a secchi disc; and pH level was determined using a pen-type pH meter (Milwaukee). Temperature and dissolved oxygen were determined using a DO meter (Cyberscan DO 110). Univariate Analysis of Variance and Tukey HSD were the statistical tools used to analyze the data obtained. Results showed that overall mean depth of water ranged between 1.48 m and 1.90 m; 2.61 m and 4.92; and 2.84 m and 4.11 m in Lakes Bito, Mahagnao, and Danao, respectively (Table 1). Overall mean percent transparency were between 52.59% and 68.06 %; 40.35% and 92.37%; and 63.19% and 97.41 % in Lakes Bito, Mahagnao, and Danao, respectively. Overall mean temperature ranged from 24.99°C to 29.74°C; 20.74°C to 27.32°C; and 19.90°C to 25.60°C in Lakes Bito, Mahagnao, and Danao, respectively. Overall mean DO were between 4.04 mg/l and 10.77 mg/l; 5.37 mg/l and 13.28 mg/l; and 4.93 mg/l and 12.84 mg/l in Lakes Bito, Mahagnao, and Danao, respectively. Overall mean pH were between 6.3 and 8.3; 6.2 and 8.4; and 6.0 and 8.8 in Lakes Bito, Mahagnao, and Danao, respectively (Table 1). There were significant differences (P<0.01) in depth, transparency, temperature, and DO among the three lakes during the study period. No significant differences in pH were observed among the three lakes, although monthly fluctuations within each lake was observed.