Ben Baena
0603925
GEOG*1220*01, Dr. Richard
Kuhn
The Effect of Aquaculture on Mangroves in
the Philippines
Introduction
Philippine
mangrove forests play a highly specialized and intricate role in tropical
coastal ecosystems. Mangroves are characterized by a species of tree that have
adapted to grow in tidal flats, bordering the ocean. Mangroves thrive in the
salty coastal water, where other plant species would die. Aquaculture practices
in the Philippines have had
negative impacts on mangrove tracts, resulting in more than 337 000
hectares lost since 1925 (Samson and Rollon, 2008). The removal of mangroves
for aquaculture creates exponential environmental backlash, as the role of
mangroves is replaced with polluting aquaculture. The purpose of this paper is
to compare the benefits of aquaculture to the negative effects on mangrove
ecosystems. When considering the negative aspects of aquaculture it is also
important to provide solutions to help mitigate mangrove damage and
destruction. This paper has been organized to first provide a background on
mangroves and Philippine aquaculture, specifically brackish water ponds. The
second portion of this paper is to provide information on the damages caused by
aquaculture unto mangrove ecosystems and the environment. The third portion
provides solutions to the problems facing mangrove ecosystems because of
aquaculture. This paper looks to inspire and educate on the relationship
between aquaculture and mangrove ecosystems in the Philippines.
The Benefits of Mangroves
Mangroves
provide countless benefits to coastal and inland ecosystems.
Acting as a boundary between ocean
and land, mangroves help to buffer and dissipate wave energy. As sea levels
rise, coastal erosion is degrading the shores and depositing sediment into the
ocean. Mangroves work against erosion by providing a layer of protection
against ocean waters. The physical nature of mangrove trunks buffers the force
of waves, preventing the full strength of the wave from reaching the coast.
Also, the roots of mangrove trees help stabilize shoreline sediments, holding
soil and preventing erosion. Loss of mangrove vegetation leads to loss of
coastal shore and total land area, as land is washed into the ocean.
The biodiversity
of mangroves provides one of the most unique and specialized ecosystems in the
world. The unique characteristic of rhizophora, mangrove trees, is that they
thrive in salty water, creating a spawning and maturing area for countless fish
species. Besides offering a physical enclave for fish habitat, the fallen
leaves and dead plant material of mangroves provide rich sustenance for fish
populations. Without the protection of mangroves infant fish would be easy prey
and therefore be unable to reproduce.
The intense
biodiversity of mangroves also helps to process wastes and pollution form the
surrounding environment, especially aquaculture. Mangrove filters have been
recommended as a solution for processing excess nitrogen waste from shrimp
farms (Primavera, 2000; Baliao and Tookwinas, 2002).
The Benefits of Aquaculture
In 1994, the
Philippines accounted for 2% of global aquaculture production (FAO, 1996), and
in 2004 Philippine aquaculture contributed 1.8 percent of the GDP. Along with
providing capitol to the Philippine economy, aquaculture employs over 1 million
Philippinos (Rafael D. Guerrero III, 2008). Based on the growing contributions
of aquaculture, the Philippine government has given it high priority in the
Medium-Term Philippine Development Plan (2004-2010), as it is expected to
produce 842 674 metric tons annually by 2010. Aquaculture is invaluable to the
Philippine economy, as 40% of the country lives in abject poverty (Mark Doyle,
2008).
A starving
population that experiences food shortages and rising prices on a regular basis
compounds Low GDP. Aquaculture helps remedy the problems of a food crisis, by
providing access to an inexpensive and nutritious source of food. In 2003
aquaculture products provided 56% of the animal protein consumed by Philippinos
(Rafael D. Guerrero III, 2008). In a third world country, aquaculture has a
positive influence providing economic and nutritional benefits.
The Negative Effects of Brackish Water Ponds on Mangroves
Despite the
beneficial economic aspects of aquaculture, there are many externalities
associated with its operation. Aquaculture takes a heavy toll on mangrove
ecosystems, as large swathes are deforested in order to create aquaculture
environments. The proximity to the ocean is desirable for fish and shrimp
farming, because of a large water supply. Effluent from aquaculture is also
diluted in the ocean, during heavy rains. Mangrove areas provide perfect inlets
for the construction of brackish and fresh water ponds, and marine pens.
Figure 1. shows brackish water ponds
as the predominant source of aquaculture fish (Philippine Bureau of Fisheries and Aquatic Resources, 2005) It is
estimated brackish water ponds are responsible for 50% or 141 000 hectares of
mangrove loss in the Philippines (Primavera and Agbayani, 1996). The
environmental problems associated with brackish water ponds have ramifications
on inland and coastal ecosystems. To maximize profit and economic viability,
brackish water ponds can be stocked with
Figure
1: Fish Production from Aquaculture by Culture System in the Philippines (Philippine Bureau of Fisheries and
Aquatic Resources, 2005)
upwards of 1 400 fish per hectare (Rafael
D. Guerrero III, 2008). The high density of marine life poses many health and
environmental problems, as it is a breeding ground for disease and pathogens.
The 1990’s saw unprecedented shrimp farm decimation due to self-pollution. The
island of Negros Occidental saw decline in shrimp production, due to viruses,
resulting in 20% of total shrimp ponds being operational (Rafael D. Guerrero
III, 2008). A single bacteria, Vibrio Harveyi, was responsible for the economic
decline of an entire island’s shrimp farm production. Yellow Head Baculovirus
and White Spot Disease are also responsible for the decline in brackish pond
productivity. As brackish water shrimp and fish farming intensify, the effluent
and waste buildup increases the breeding of bacteria and pathogens.
The
waste from brackish water shrimp ponds has ramifications for inland and coastal
ecosystems far away. Non-sustainable shrimp farming results in the
eutrophication of fecal matter and nutrients. Intensive brackish water shrimp
farming creates acid sulphate soils (NJ Stevenson). The high concentration of
acid sulphate renders the aquaculture farm useless, as it becomes unbearable
for any species. Mangroves cannot reclaim areas with high acid sulphate levels
because the soil is too poisonous. Rehabilitation is an extensive process
requiring the area to be flushed by the ocean. Flushing the unused ponds is a
labour intensive process, as upwards of 150 flushes maybe required in order to
remove the salts (NJ Stevenson). Flushing brackish ponds is a spatial
displacement of the waste, diluting it in the ocean.
Calatagan,
a small town south of Manila, has been devastated by its mangrove loss. A wealthy
lawyer and fish farm owner skirted the law against mangrove removal by damning
off water to the thriving mangrove ecosystems. The mangroves died and were
subsequently replaced by brackish water fishponds. As a result of the removal
of mangroves for aquaculture purposes, the community suffered; their ground
water became contaminated with salts, and their access to fishing areas was
denied. The socioeconomic externalities associated with mangrove removal are
often felt by the periphery of society, those without a voice. This case
exposes one of the main reasons for mangrove loss, despite laws against
mangrove removal, there is little enforcement. Government incentives for
aquaculture and lax enforcement of environmental laws promote aquaculture as a
means a survival for a country facing extreme poverty.
Solutions to Mitigate Damage
Despite the
severe loss of the total mangrove area in the Philippines, there are many
solutions to mitigate further damage. As awareness and understanding of
mangrove ecosystems increases, there has been greater effort for their
protection at every level. From grassroots initiatives to national policy
changes, progress is being made.
Local grassroots
initiatives are, collectively, making a national difference. The local
communities around mangroves are quickly realizing their benefits and are
making an effort to protect them. As seen in Figure 2: Initiatives of Mangrove Reforestation, the predominant
driving factor behind replanting is local government and community based
initiative. Local governments are funding the rehabilitation and planting of
rhizophora, with mixed success. Planting mangroves species in a non-native
area, or converting fishponds has limited success. Seedlings are exposed to
wind and wave stress, which results in high plant mortality. The root systems
of seedlings cannot negate wave erosion and the root systems are exposed. When
flooding occurs on mangrove plantations, the entire canopy of the mangrove
seedling is submerged, suffocating the plant. Although mangrove replanting can
be very successful, it often results in monoculture, lacking the original
biodiversity. Replanted mangrove stands are also less efficient at trapping
sediment and preventing erosion (Samson and Rollon, 2008).
The National government
has both positive and negative effects on the protection of mangrove
ecosystems. The Philippine Fisheries Code of 1998, calls for the protection and
conservation of aquatic resources, specifically it bans mangrove destruction
for aquaculture development. While mangrove removal is now illegal this law is
not regularly enforced. The Fisheries Administrative Order of 2001 called for a
Code of Practice for Aquaculture. It guidelines “aquaculture must be of
environmentally sound design and operation, for sustainable development”. While
the specific guidelines are vague, it is another step toward better
environmental practices.
Figure 2: Initiatives
of Mangrove Reforestation (Samson and Rollon, 2008)
The Philippine
government also controls brackish water ponds through 25-year
lease agreements. In the mid 80’s
to 1990’s it provided several lease agreements to boost economic potential that
cleared the way for mangrove deforestation. Owners of lease agreements are
unlikely to revert their aquaculture farms back to mangroves due to loss of
income (Samson and Rollon, 2008).
The
easiest and most effective solution to mitigate aquaculture damage on mangrove,
takes place before the aquaculture infrastructure is built. Selecting the most
appropriate type of aquaculture best suited for the environment, often results
in decreasing environmental damage. Off shore marine pens are a way to raise
and contain fish without mangrove destruction. Holding nets are placed off
shore, where fish are raised in captivity. There is less convenience compared
to fishponds, but no mangroves need to be deforested. Mangroves can also be
integrated into aquaculture design as to produce more yield and profit.
Mudcrabs have been successfully raised in mangrove pens. Stocked pens with 5-7
mudcrab / sq m. at a weight between 150-200g resulted in a higher yield. After
10-15 days the mudcrabs weighted between 200-250g at a net income of 80 cents
per kilo (Guerrero, 2000). This lucrative business utilizes mangroves for
protection of mudcrabs and as a fertile feeding ground.
Integrating
agriculture and aquaculture is another solution to the environmental damage of
brackish water ponds. In several cases rice paddies have been stocked with
ammonia producing fish such as tilapia. Rice greatly benefits from the ammonia
rich excrement of tilapia, which results in less pesticide and fertilizer use.
The raising of tilapia and rice is a common practice in China and Vietnam that
is now taking hold in the Philippines. Inland rice and tilapia operations
require no destruction of mangrove ecosystems, as they are fresh water.
Consumer
awareness can play huge role in the export of aquaculture products, as
consumers become more environmentally engaged. Labeling fish products with
their environmental sustainability can force producers to re-examine their
aquaculture practices. As demand for more ecologically conscious food rises,
aquaculture would take on more sustainable development.
Conclusion
Mangrove
destruction in the Philippines due to aquaculture is a serious problem.
Aquaculture plays a large role in the destruction of mangrove ecosystems, as
thousands of hectares of mangroves are deforested to create space for ponds.
The removal of such a delicate and specialized ecosystem poses many
environmental problems. Mangroves help to anchor coasts against the powerful
forces of the ocean and provide a unique habitat for countless fish species.
Comparing the socioeconomic benefits of aquaculture with the removal of
mangroves is a difficult balancing act. One must consider the externalities and
environmental ramifications associated with losing a valuable ecosystem.
Improvements to
aquaculture design and infrastructure along with rehabilitation efforts have
helped reduce damage to Philippine mangrove ecosystems. The best solution to
prevent mangrove destruction is to create an appreciation for the important
role mangroves play. Figure 2 shows an increasing appreciation of local
communities towards mangroves, which has resulted in communities taking an
active role in mangrove rehabilitation. By re-analyzing aquaculture practices
to best suit the environment, sustainability can be achieved. Sustainability is
key, to ensure continually viable aquaculture production and everlasting
mangrove ecosystems.
Hopefully future
generations will be able to absorb the beauty and diversity contained within
mangroves.
Works Citied
Baliao, D.D., and S. Tookwinas. Best Management Practices
for a Mangrove-Friendly Shrimp Farming, Aquaculture Extension Manual No. 35.
Philippines. Aquaculture Department. Southeast Asian Fisheries Development
Centre. 50-50.
Doyle, Mark. "Philippines suffers poverty divide."
BBC News. 4 Sept. 2005. BBC. 30 Oct. 2008
<http://news.bbc.co.uk/1/hi/world/asia-pacific/4245422.stm>.
Guerrero III, Rafael D. "A Fisheries School Where
Students Learn to Earn." Agriculture IV (2000): 18-19.
Guerrero III, Rafael D. Eco-Friendly Fish Farm Management
and Production of Safe Aquaculture Foods in the Philippines. Philippines.
Philippine Council for Aquatic and Marine Research and Development. Laguna,
2008.
Primavera, J.H. "Integrated Mangrove-Aquaculture
Systems in Asia. Integrated Coastal Zone Management." 121-30.
Primavera, J.H., and Agbayani, R. F (1996) Comparative
strategies in community based mangrove rehabilitation programs in the
Philippines. Page 34 In Proceedings of the ECOTONE V Regional Seminar:
Community Participation In Conservation, Sustainable Use and Rehabilitation of
Mangroves In Southeast Asia, Ho Chi Minh City, Vietnam, 8-12 January,1996.
Mangrove Ecosystem Research Centre (MERC), Vietnam National University, Vietnam
Samson, Maricar S., and Rene N. Rollon. "Growth
Performance of Planted Mangroves in the Philippines: Revisiting Forest
Management Strategies." Ambio 37 (2008): 234-40.
The State of World Fisheries and Aquaculture. PublicationNo.
Food and Agriculture Organization of the United Nations (FAO), United Nations.
Rome: FAO, 1996. 12-12.
Stevenson, N.J. "Disused Shrimp Ponds: Options for
Redevelopment of Mangrove." Coastal Management 25: 423-25.
TA: *** **********
Comments:
Hi ********,
Great proposal! You have an interesting topic and are on your way to preparing a strong
essay. Here are some comments and suggestions:
(1) Please respect the length limit for the essay. You were to use double spacing in your proposal (single is okay for the annotated bibliography).
(2) Your solutions and key issues are well developed and nicely organized!
(3) Proofread your proposal (particularly the annotated bibliography, where some info. was missing).
Please let me know if you have any questions re: the above comments.
