BALANCE OF BIODIVERSITY
BALANCE OF BIODIVERSITY
Pardon me, but I am going to touch on a very sensitive topic that may cause some people to become mad at me. Before I proceed any further, I want to make it clear that I am an advocate of livelihood for everyone, and I do not mean to harm or disturb the livelihood of others, especially our poor farmers. That said, I humbly suggest that we should think about how some invasive species of fish are affecting the balance of our biodiversity, even if these are also providing us with our means of livelihood.
Just to be clear, I am not recommending any action yet. My only recommendation at this point is to start the debate on this issue, so that we could arrive at a good decision about what to do next. In fairness to everyone, however, I would like to recommend a neutral party that could moderate the debate, so that there will be no bias. Instead of suggesting the DA or the DENR to become the moderator, I am suggesting DepDev instead. That is what I mean by a neutral moderator.
What good will it do for our country if we make money from raising invasive species and yet also lose money because of the damage to our biodiversity? It is obvious that what we need is a serious techno-economic study that DepDev is very qualified to do; therefore they should be tasked with it. If DepDev decides to accept the challenge, all government agencies should cooperate with them, and give them the data they need. The task will involve a lot of econometrics, data analytics and perhaps also artificial intelligence. The final output should be a recommendation from DepDev whether or not we should resign to the reality of invasive fish. In other words, to give up eradicating them. If DepDev says otherwise, then we should do everything to eliminate them in all our bodies of water. Meanwhile, we should totally eliminate the useless species such as janitor fish and knife fish.
Background: the case of “pla pla” (Nile tilapia, Oreochromis niloticus)
You already laid out many of the key facts: pla pla was introduced in the Philippines around the 1970s (though some references indicate even earlier introductions via fishery programs). It grows fast, reproduces quickly, competes with native fish for food and habitat, degrades habitat, and is reported to contribute to the decline—and, in some cases, extinction—of native species, particularly in places like Lake Lanao. The Bureau of Fisheries and Aquatic Resources (BFAR) classifies it as an invasive exotic species.
But there is also data showing that tilapia and other introduced freshwater fishes have made significant contributions to fish production in the country. In 2012, for example, cultured tilapias, carps, catfishes contributed over ₱20.16 billion in value, producing some 290,513 metric tons to the farmed fish production. From inland freshwater sources, introduced fishes (tilapia, carp, mudfish, catfish, gourami) produced over 88,000 MT worth more than ₱5.3 billion.
So yes: livelihoods, food security, incomes are all on the side of tilapia. We can’t dismiss that easily.
What is DepDev and why they are well-positioned
DepDev is the Department of Economy, Planning and Development, the newly created executive department under Republic Act No. 12145, which reorganized the former National Economic and Development Authority (NEDA). Among its mandates are socioeconomic planning, coordination, monitoring and advising policymakers.
Given this, entrusting DepDev with assessing the trade-offs of invasive species seems reasonable. They have the institutional legitimacy, access to data, capacity (assuming sufficient resourcing), and mandate to convene stakeholders. Also, with long-term planning law (they are tasked with a 25-year infrastructure master plan, etc.), they already deal with balancing long-term costs and benefits.
What do we know and what remains unclear
From scientific studies:
A recent paper (on aquaculture in a Malaysian reservoir) shows that native fish catch (CPUE = Catch Per Unit Effort) is significantly lower in sites near tilapia cages compared to distant sites. Several native cyprinid species show >50% reduction in abundance near tilapia cages.
Overlap in diet and habitat between tilapia and many native species means that tilapia are outcompeting them both for food and for reproductive grounds.
On the Philippine side, there is some contradictory evidence: some studies report no evidence of adverse effect on native fish fauna when tilapia are introduced into certain lakes/reservoirs, while others warn about habitat degradation, competition, and loss of biodiversity.
Also important: much is unknown. The ecological impact of many introduced freshwater fish species is poorly documented. According to one review, 62% of introduced freshwater fishes in the country have “unknown” ecological impact, 54% have “unknown” socio-economic impact,
My thoughts, questions and suggestions
Trade-off awareness
We must openly recognize that there are trade-offs: food, livelihoods vs biodiversity loss. The poor farmers and fishers depend on tilapia (and other invasive species) for income and sustenance. Eliminating them cold turkey could hurt vulnerable groups unless there are alternatives.Transparent data gathering & public engagement
A techno-economic study must be transparent, participatory, inclusive. Involve local fishers, environmental scientists, economists, community leaders. Ensure that local knowledge is respected.Define criteria for decision
What counts as “too much damage”? Is loss of certain native species irreversible? How to value ecosystem services lost (water quality, recreational fishing, ecotourism)? How to compare with income gains from invasive species farming?Possible policy options
Management rather than total eradication: e.g., containment, confinement (ponds), avoiding escapees.
Selective elimination in high priority ecosystems (rivers or lakes with endangered natives) but allowing on farms under regulation.
Genetic, biological, or ecological control measures (though risky).
Incentives for farming native species or for cultivation systems that reduce the invasiveness (closed systems, controlled stocking, etc.).
Regulatory and institutional framework
We have the National Invasive Species Strategy and Action Plan (NISSAP) 2020-2030 that aims to address IAS (Invasive Alien Species). Implementation seems weak, and enforcement issues remain. A multi-agency task force is needed (DENR, DA-BFAR, LGUs, academe).Economic valuation of costs
There is a study that says invasive species cost Southeast Asia about US$33.5 billion per year (losses in agriculture, environment, human health). By knowing similar estimates for the Philippines, we can measure whether benefits from tilapia outweigh hidden costs from biodiversity losses.Role of DepDev
Commission the study: ecological, economic, social dimensions.
Publish interim findings so public debate can happen.
Ensure legal, budget, and institutional support: data from BFAR, DENR, PSA (Philippine Statistics Authority), academe.
Possibly design compensation or support mechanisms for communities that might be adversely affected under stricter regulation.
Questions to ask
What is the real cost to ecosystems and native species in terms of biodiversity loss, which could translate into losses in ecotourism, cultural heritage, water quality, and resilience?
What are current levels of dependence of fishers, farmers on invasive species for income? Do they have alternatives?
Are there successful case studies—either in the Philippines or elsewhere—where invasive fish have been managed without harming the livelihoods of small farmers?
What are the risks of eradication: environmental, social, economic? Could removal of an invasive species cause unintended damage?
My view / suggestion
If I were to decide, I would lean toward a balanced management approach, not total elimination at this moment. Here's why:
The benefits (food, jobs, income) are real and important, especially for the rural poor.
But uncontrolled spread of invasive species risks irreversible losses of native biodiversity, which in the long run could undermine ecosystem services (clean water, natural fish stocks, ecological resilience) that even fish farmers and consumers depend on.
So, I suggest that we:
Task DepDev with a major study, as proposed.
Meanwhile, strengthen enforcement of measures to prevent escape of tilapia from farms; designate protected water bodies where invasive species are strictly controlled.
Promote aquaculture of native species in parallel (e.g., stock enhancement, culture of indigenous fishes).
Possibly provide subsidies or transition assistance to fish farmers should stricter regulations be imposed.
Let me end with this: what is the kind of country we want in 25, 50 years? One where short-term incomes dominate while we lose our unique lakes, rivers, and native species — or one where biodiversity, culture, and livelihood all survive together? If DepDev helps us frame that debate well, then perhaps we will arrive at the right decision — not easy, but necessary.
Ramon Ike V. Seneres, www.facebook.com/ike.seneres
iseneres@yahoo.com, senseneres.blogspot.com
02-15-2026
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