World Aquacluture Magazine - September 2020

WWW.WA S.ORG • WORLD AQUACULTURE • SEP TEMBER 2020 35 be advantageous and disadvantageous. Tilapias are efficient feeders because of physiological adaptations that allow them to capture and digest a wide range of natural food items and can grow very fast for 4-5 mo. Some tilapias can grow up to 61 cm long but the marketable size is usually about 220 g. Among others, these features make it an ideal species for aquaculture (Loiselle 1994, Anonymous 2016). Opportunities inTilapiaAquaculture The benefit of introducing tilapia in aquaculture include provision of livelihoods, economic development and fisheries enhancement. Inland freshwater aquaculture of tilapia is more accessible to financially disadvantaged communities because it requires only low capital investment. An operation can be started with a mere cage. Because of this, average tilapia production in 2010-2014 added 43 percent to the world’s total tilapia production, with the Philippines as the top contributor among ASEANMember States, having almost 223,167 t or almost 80 percent in volume at about US$ 390 million or more than 81 percent of value (Cuvin-Aralar 2016). Global tilapia production has steadily increased at around 3-4 percent since 2018 to around 5.74 million t, despite the slowing of overall growth. The Philippines was expected to have a total of about 1.21 million t in 2018 (FAO 2019). Nile tilapia has received the most attention among tilapia species due to its fast growth rate (Canonico et al. 2005, Guerrero 2019) and millions of dollars have been invested in research to improve the performance of this fish (Ponzoni et al. 2011). At present, a new “Molobicus” hybrid tilapia has been developed that is the result of repeated crossing and backcrossing of Nile tilapia andMozambique tilapia. This hybrid is more salt tolerant and has a fast growth rate (Guerrero 2019). The new set of characteristics of this hybrid is crucial because they may now inhabit the abundant brackishwater environments of the Philippines. P hilippine aquatic ecosystems are home to many tropical aquatic organisms. Such biodiversity, however, does not translate to a level of aquatic food production sufficient for poverty alleviation and economic improvement. Fish production through wild capture has steadily declined due in part to destruction of coral reefs. Total fishing effort has increased by more than 3.4 times and destructive fishing practices, despite being banned, have had adverse effects on coral reefs (BusinessWorld 2018, Selgrath et al. 2018, UBC 2018). Fish production in the Philippines has declined somewhat (Table 1) but has basically been static between 2011-2018 (BFAR 2013, BFAR 2018). Freshwater fish, specifically milkfish and tilapia, are the top fish commodities consumed by Filipinos. Because of higher demand but limited supply, fish retail prices have increased more than those of other basic farm commodities (Table 2, UBC 2018, BusinessWorld 2018), placing a lot of Filipinos, especially the poor, at a great disadvantage. To address this issue, local government agencies such as the Department of Agriculture (DA) and the Bureau of Fisheries and Aquatic Resources (BFAR) launched the “Balik Sigla sa Ilog at Lawa” (Revitalize Rivers and Lakes) or BASIL program in 2017. The project aims to remedy food scarcity and provide economic stability (Gonza- les 2017, BFAR 2018) by stocking local bodies of water with fish that can potentially boost the aquaculture industry. The BASIL program is being frowned upon by those concerned with ecosystem biodiversity where alien invasive species (AIS) were introduced. Opposition to the program is based on the invasiveness of these “acceptable fishes” (An- derson 2016) and the low capability level of local government units to monitor the program (Agasen 2005, Cuvin-Aralar 2016). Tilapia Tilapia is a popular fish cultivated in different parts of the globe, mainly for food but also for control of aquatic weeds, mosquitoes, or even other tilapia species. It has been introduced into ecosystems through human intervention, although not always necessarily intentionally. The impact of tilapia on the environment as an AIS can Alien Fish Species Introductions to Philippine Waters Janice A. Ragaza, Edgar J. Morata, II and Adjale G. Wyson ( C O N T I N U E D O N P A G E 3 6 ) Tilapia production requires low capital investment. Tilapia grow fast, reaching marketable size of 220 g in 4-5 months (Photo: E.J. Morata). TABLE 1. Eight-year fish production trend in the Philippines from 2011–2018 (BFAR 2013, BFAR 2018). Year Quantity (in ‘000 t) Change (%) 2011 4,974 -3.60 2012 4,865 -2.20 2013 4,705 -3.30 2014 4,689 -0.35 2015 4,649 -0.85 2016 4,356 -6.31 2017 4,312 -1.00 2018 4,357 +1.04