38 DECEMBER • WORLD AQUACULTURE • WWW.WAS.ORG In response, projects such as FISHSTRAT began the first surveys in Taal, characterizing the lake’s fish biomass, zooplankton, and phytoplankton, and spearheading much of the post-boom research in the lake (Papa and Mamaril 2011). The research trend has largely been the same in the past 30 years, with aquaculture use being the main reason for the continued investigation and monitoring (De Leon et al. 2023), attempting to guide policymakers in making aquaculture in the region more sustainable. Fifty years after the first aquaculture farms were laid upon Taal’s waters, the vast undertaking of keeping the lake alive perseveres. In 2013, SEAFDEC aided in the collection of baseline data in the newly established 1000-hectare Fish Reserve Area in Taal (Mutia et al. 2013). The FFRDC that was acquired in 1986 remains active and has continued to help predict potential fish kill events (De Castro 2023). In addition, a FASCICLE (French Asian Study on Global Change Effects through Inter-Site Comparisons of Limnic Ecosystems) study on fish kills was recently published in conjunction with BFAR and UST (Mendoza et al. 2019). This study effectively tracked water quality parameters and weather trends that preceded fish kills in the lake. Aquaculture remains a large factor to this day, with fish cages contributing higher nutrient levels that raise microbial activity, ultimately lowering dissolved oxygen levels (Mendoza et al. 2019). The DENR threshold for DO is set at 6.0 ppm, which the study found was crossed five times from 2000-2011 (Mendoza et al. 2019). Half a century strong, the sustainability of Taal’s aquaculture industry relies on the foundation of continuous monitoring established in the 80’s. From Past to Present The Philippines, being an archipelago, is no stranger to water. In fact, numerous tourist destinations have revolved around such environments like the Puerto Princesa Underground River, the Hinatuan Enchanted River, Boracay, and even the numerous islands to visit in Pangasinan. In the city of Batangas, Taal Lake serves not only as a tourist attraction hosting Taal volcano, but also as a site of culture, recreation and livelihood for the locals. With the lake playing such a crucial role in their lives, how is it that there appears to be an endless supply of resources for locals to harvest? To answer that question, we took a glimpse at the reality of Laurel, Batangas and the community’s relationship with the lake (Figure 6). Through ongoing aquaculture development and regulations, locals have achieved a sustainable balance that benefits both people and the environment. This, however, was not always the case as the endemic species of sardines, Sardinella tawilis, was declared endangered by the International Union for Conservation of Nature (IUCN) in January 2019. S. tawilis is the world’s only freshwater sardine which adapted to the hydrobiological changes in Taal Lake (Mamaril 2001). Having established its population, the freshwater sardine has become one of the most commercially important fish from the area (Mutia et al. 2018). At its peak, 29,000 MT of tawilis was produced in 1984 (BFAR) with production subsequently dwindling and reaching a low of 290 MT in 2000 (Mutia et al. 2004). Interestingly, this freshwater sardine is the only other commercially fished endemic species in the Philippines alongside Mistichthys luzonensis, or more commonly known as “Sinarapan” (Pardo et al. 2023). In the year 2020, tawilis production rose to 527.95 MT ranking 12th in the Philippines in terms of inland municipal fish catch (BFAR). Having such economic impact, S. tawilis became a target for overexploitation which alongside the threat of pollution has led to their large decline, leading towards extinction. Being notified of the potential loss of the freshwater sardine, the Philippine government established a closed season for tawilis fishing to allow for the replenishment of new stocks. With strict regulations being set to control S. tawilis populations, one might wonder how the locals are able to deal with seasons when the commercially important species is not available for harvesting. However, another commercially important species for the nation is present - Tilapia. Tilapia belong to the Cichlidae, one of the most speciesrich families of fish with over 1600 valid species taxa (Dunz and Schliewen 2013). Their diversity has attained research interest especially with the East African cichlid radiation (EAR) endemic to Lakes Malawi, Tanganyika, and Victoria becoming evident (Kornfield and Smith 2000). In the Philippines, one species of Tilapia has become a staple in not only household meals, but as a commercial product. Since its first introduction to the country Oreochromis niloticus, Nile tilapia, has been a commercial success contributing to the country’s fish production. Furthermore, Dr. Rey Donne S. Papa, Dean of the University of Santo Tomas College of Science, has stated that proliferation of tilapia has reached a “point of no return,” and the most apt way of responding to this situation is simply utilizing the fish in any manner possible. FIGURE 6. Barangay Berinayan, Laurel, Batangas, home to aquaculture farms like Diamond Harvester. Photo credit: L. Deza. FIGURE 7. Mr. Rex Salvador, one of Diamond Harvester’s managers and founders. Photo credit: R. Begtang
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