World Aquacluture Magazine - September 2020

38 SEP TEMBER 2020 • WORLD AQUACULTURE • WWW.WA S.ORG However, the intent for greater fish production and socio-economic advancement by the introduction and dispersal of millions of alien species could pose a threat to freshwater biodiversity in the Philippines. In its five-year plan, the BASIL program covers 13 major lakes and river systems, including Buluan Lake, Laguna Lake, Lanao Lake, Lake Mainit, Naujan Lake, Lake Sebu, Taal Lake, Abra River System, Agusan River Basin, Bicol River Basin, Cagayan River Basin, Mindanao River Basin, and Pampanga River. The program has a target release of 126.82 million fingerlings by 2022 (Table 3). The Fisheries Quarterly Performance report data has recorded initial success of the program; an increase of 498,960 t, or 5.81 percent increase in the volume and value of fisheries production in the second quarter of 2018 (FSR 2018). Aside from the 13 major lakes and river systems, fingerlings will be released to other lakes and river systems in the country. These water bodies have 120 fish species that are endemic to the country (Froese and Pauly 2019). Introduction of exotic species has the potential to alter existing endemic fish populations through species interbreeding, predation, competitive exclusion by competition for food, space, and habitat, niche displacement, alteration of habitat, parasite infection of other species, and extinction of native species (Araullo 2001, MacKinnon 2002, Joshi 2006). Although the BASIL programwas started with good intentions, the public holds varying perspectives and opinions. Opposition to the program is based on the invasiveness of “acceptable fishes” such as tila- pia, milkfish, and carps among others. The lack of predators could cause AIS to multiply uncontrollably. Moreover, juveniles of AIS could prey upon native predators of the ecosystem, but as these fishes are character- ized by rapid growth, predation decreases as well (Anderson 2016). Opposition is also based on the lack of capability of the local government units to monitor the program. Projects involving AIS are not new and often the impacts of AIS have not been considered. Mismanagement has allowed AIS to become established in areas where introduced. More than 76 introductions of fish and other species have been reported since 1907. Among Asian countries, the Philippines ranks first as having the greatest number of introduced aquatic AIS (115 species) followed by Singapore (95 species) and Indonesia (52 species) (FAO 2019). Invasive species control measures have been implemented in Pasig andMarikina Rivers, Lake Paitan in Nueva Ecija, Laguna Bay, and AgusanMarch inMindanao, where the South American janitor fish (armored catfish) Pterygoplichthys gibbiceps has become invasive (Agasen 2005, Cuvin-Aralar 2016). Most endemic cyprinids in Lake Lanao were reduced in number because of the introduction of the white goby and eleotrid (Juliano et al. 1989). There was loss of biodiversity of the native bighead catfish in many freshwater ecosystems due to the introduction of the walking catfish. Alien species are usually introduced to boost economic performance, without careful consideration of local biodiversity (Joshi 2006). Approaches to Control andMitigate AIS It is important to develop control mechanisms for AIS to mitigate potential damage. Populations of AIS often grow very quickly, soon outnumbering native species. Often too, AIS lack natural predators to keep populations in check. As mentioned above, predation by native species on newly-spawned AIS is not always effective as a biological control method, so other options must be considered. In the USA, AIS have been consumed as pet food or fertilizer (Phelps 2016). Control measures include using bubble curtains technique to deter the movement of Asian carps (Zielinski and Sorensen 2016). Carbon dioxide can also be used as a deterrent to bighead carps, which avoid areas with high concentration of this gas (Donaldson et al. 2016). Pheromones can be used to capture and deter AIS populations (Little et al. 2014). Legal Frameworks for Sustainable Development and Good Aquaculture Practice The Philippines is endowed with bountiful natural resources, including water bodies that are very significant in facilitating the country’s economic development (Rubio 2008). The inland freshwater resources of the Philippines consist of 200,000 ha of lakes, 106,328 ha of swamplands, 31,000 ha of dams and reservoirs, 1,000 ha reservoirs, 421 principal river basins, 72 lakes, 18 major river basins, and extensive groundwater aquifers (Guerrero 1995, Tuddao and Gonzales 2016). These resources host some 346 species in the country, of which 14 percent are introduced, 35 percent are endemic, and 31 percent are threatened (Froese and Pauly 2019). Interventions fromBFAR and other government sectors have con- tributed to an increase in fisheries production. Among the three subsec- tors of fisheries, the aquaculture sector gives the highest total volume production (5.8 percent increase) as compared to municipal (2.5 percent decline) and commercial subsectors (2.3 percent increase from previous year). The decline in fisheries production was due to lowwater levels in lakes and unfavorable weather conditions such as typhoons (FSR 2018). Despite the promise of aquaculture, current government efforts in this area are not sufficient to substantially increase fish production. Given the many underutilized water bodies in the country, the BASIL programwould mean greater harvests by fish farmers. The TABLE 2. Average annual prices of selected fish species in the Philippines in US$ per kg (Businessworld 2018, The University of British Columbia 2018). Fishery product 2013 2014 2015 2016 2017 Milkfish Wholesale 2.37 2.29 2.30 2.20 2.13 Retail 2.92 2.78 2.74 2.66 2.64 Tilapia Wholesale 1.74 1.77 1.76 1.72 1.65 Retail 2.31 2.31 2.34 2.25 2.20