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ECONOMIC ANALYSIS OF SILVOFISHERY PONDS AS AN EFFORT
TO UTILIZE SUSTAINABLE MANGROVE ECOSYSTEMS
Introduction:
Mangrove forests have complex functions. Experts argue that mangrove forests have
physical functions, biological functions, and potential economic functions. Bann (1998) and
Kusmana et al. (2005) suggested the physical function of mangrove forests, namely for
breakwaters, coastal protection from abrasion, preventing seawater intrusion into the
mainland, processing organic waste, retaining mud, and trapping pollutants. Biological
functions as a spawning ground and post larval growth (nursery ground) of fishery
commodities, food providers for organisms living around mangrove ecosystems, protectors of
biodiversity, and as carbon sinks and oxygen producers. According to Saenger et al. (1981)
and Arief (2003) as an economic function of mangrove forests is a source of income for the
community, industry, and the state. Mangrove forests can be used as land for ponds, salt
making, recreation, and can produce wood. Given the complex function of mangrove forests,
the existence of mangrove forests must be managed optimally and preserved both in quantity
and quality.
The enormous potential of mangrove resources requires the concept of sustainable
utilization, but in reality in the implementation of such management the sustainability factor
of natural resources (SDA) is often ignored. This can be seen in the alarming degradation of
natural resources in various regions and management policies that often reinforce the
tendency to overexploit resources.
The potential of mangrove ecosystems to improve people's livelihoods has led to high
levels of exploitation of mangrove forests (Olfie et al. 2011). Mangrove forest areas are under
serious pressure on their ecological functions due to coastal development, mining, conversion
of land into salt ponds and agriculture, and conversion of forests into aquaculture ponds or
ponds. Continuous utilization without regard to sustainability will exceed the production
capacity of mangrove forests so that ecosystems and habitats associated with these
ecosystems are damaged.
Indonesia's mangrove area is the largest in Asia, accounting for 49% of the total
mangrove area and containing 43 different mangrove species. The condition of mangrove
forests experienced the greatest decline in the 1980s (FAO 2007). In 1980 Indonesia's
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mangrove forests covered an area of 4.2 million hectares and in 2009 the mangrove area
dropped to
less than 1.9 million hectares. The conversion of mangrove forests into ponds is the main
cause of the decline in mangrove area (Balitbang
Forestry 2013). After the decline in mangrove area, people began to feel the importance of
mangrove forests and began to realize the benefits of the mangrove ecosystem. The Ministry
of Forestry (2013) recorded rehabilitation efforts from 2008 to 2013 with a total addition of
79 thousand hectares of mangrove forests.
Belawan Sicanang is one of the villages in Medan Belawan Sub-district, North Sumatra
Province which has a mangrove forest area of 125 hectares and has been damaged by 94
hectares (75.20%). Mangrove forest damage is classified as a severe condition 72 Ha
(76.60%) of the 94 Ha mangrove forest damage area (Fadhlan 2011). Over the past four
years, Belawan Sicanang Village has always been affected by tidal flooding. One of the
factors causing tidal flooding in Belawan is the rampant opening of ponds that encroach on
mangrove forest areas. Tidal flooding hampers economic growth in Belawan and requires a
very large amount of countermeasure funds (Medan Bisnis June 8, 2013).
The Law of the Republic of Indonesia No. 4 of 2009 concerning Basic Provisions for
Environmental Management states that every natural resource must be managed with an
environmental perspective, so in the application of the mangrove forest management system
it is necessary to pay attention to several principles, namely the principle of sustainability of
mangrove forest functions, maintenance of mangrove forest ecosystem life nets, maintenance
of biodiversity, control of negative impacts and increase in positive impacts of development
mangrove forests, and awareness from various parties of the position of mangrove forests as
common property.
To overcome the diversion of mangrove forests into fish ponds, the Ministry of
Forestry introduced mangrove utilization called "Silvofishery" in the form of intercropping.
Silvofishery is an integrated form of mangrove cultivation with brackish water ponds
(Balitbang Kehutanan 2013). The relationship is expected to form a balance so that ponds
that ecologically have a lack of producer elements that must be supplied through feeding will
be supplied by the presence of subsidized producers (marine biota) from mangrove forests
(Fitzgerald and Sutika 1997). In addition to ecological benefits, the community also gets
additional economic benefits from mangrove wood produced.
Under the supervision and guidance of Perhutani, the community is encouraged to replant
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mangroves around their ponds to maintain the mangrove forest ecosystem. These efforts are
made to rehabilitate mangrove forests and also support the economy of the people who live
around them. This is what makes this research important to do, namely to assess whether
silvofishery utilization patterns are more profitable than non-silvofishery utilization patterns
and ensure the sustainability of utilization by surrounding communities who depend on
mangrove forests.
1.1 Problem Formulation
Canang Kering Village is a village located in Belawan Sicanang Sub-district, Medan
Belawan District, Medan City, North Sumatra Province. Canang Kering Village is a coastal
area where the existing mangroves have been damaged because many are converted into
ponds and result in frequent tidal floods (tidal floods) that hamper activities and harm the
community's economy (Medan Bisnis June 8, 2013).
Amid the increasingly severe damage to mangrove forests in Belawan Sicanang Urban
Village due to human activities, since 2010 pond farmers realized the decline in
environmental quality and applied to the Forestry Department for training in silvofishery
pond systems. Farmers who have converted mangrove ecosystems to open ponds are
encouraged to replant mangroves in the application of silvofishery pond system. Silvofishery
ponds are a form of rational approach in its utilization by involving communities around the
area that utilize mangrove forests directly (Balitbang Kehutanan 2013).
In reality, not all farmers want to implement silvofishery pond system, so it is necessary
to identify the factors that influence farmers in making decisions to choose the pond system.
The results of the comparison of the income of farmers and the benefits of the presence of
mangroves on the productivity and sustainability of ponds is expected to increase community
participation in implementing silvofishery pond system. Problems that arise in this study are:
1) What is the condition of aquaculture and mangrove potential in Belawan Sicanang Village?
2) How much income is generated from silvofishery and non-silvofishery farming systems?
3) What are the advantages and disadvantages of silvofishery farming systems?
financially and economically?
4) What factors influence farmers' choice of silvofishery system?
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2.1 Mangroves
2.1.1 Mangrove Ecosystem
Mangrove ecosystems include coastal ecosystems or shallow marine communities that
are interesting, mangroves live in extreme environments because they require salty water
(water salinity), muddy, and always flooded (Irwan 1992). Mangrove vegetation grows and
develops well on beaches that have large and sheltered rivers such as deltas and estuaries, and
can also grow in muddy coastal environments (Noor et al. 1999).
Irwan (1992) explains that some mangrove trees have special root systems. Rizophora
species have long anchor roots to prevent the growth of seedlings nearby. There are also
those that have roots that appear upright at ground level, namely from Sonneratia and
Avicennia species, as well as the existence of knee-shaped breath roots from Bruquiera
species to provide opportunities for oxygen to enter the root system. The main function of the
roots of mangrove trees, which are generally disk-shaped, is to reduce tidal currents, settle
mud, and provide a place for shrimp and fish to feed and shelter from predators.
Mangrove forests are highly productive ecosystems with a wide range of important
economic, social, and environmental functions. The depletion and decline in the capacity of
an ecosystem to meet human needs and development ultimately encourage countries to
implement a new paradigm, namely sustainable development (Kusumastanto and Meilani
1998). The uncontrolled utilization of coastal areas in the form of changing the function of
mangrove forests results in a situation that is not in accordance with the sustainable
development scenario (Indrajaya 1992).
2.1.2 Forest Benefits and Functions Mangroves
Mangrove forests are potential that can be developed in meeting social, economic and
environmental needs. Ecologically the function of mangrove forests according to Kusmana et
al. (2005), as:
1) Biological function; as a food provider for organisms living around mangroves, and a nursery
ground for shrimp, fish, and other marine life.
2) Physical functions; namely as a breakwater, protecting the coast from abrasion, preventing
seawater intrusion, retaining mud, and processing organic waste.
3) Economic function; namely as a location for making ponds, agricultural land, salt ponds,
locations for ecotourism activities, and mangrove flora and fauna that can be utilized directly.
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2.1.3 Physical Condition of Ecosystem Damage Mangroves
Mangrove forest ecosystem damage is a change in the physical condition of biotic and
abiotic in the mangrove forest ecosystem to be no longer intact (damaged) caused by natural
factors and human factors (Tirtakusumah 1994 in Rahmawaty 2006). In general, damage to
mangrove forest ecosystems is caused by human activities in the utilization of natural
resources of coastal areas that do not pay attention to sustainability, such as logging for the
purposes of excessive firewood, ponds, settlements, industry and mining.
2.2 Cultivation System Ponds
Coastal fisheries area is a place where various activities oriented to fisheries businesses,
both brackish water aquaculture, mariculture, and capture fisheries (Ditya 2007). Pond
business is an aquaculture business system that utilizes land on the coast with brackish water
conditions. Aquaculture technology can be divided into traditional, semi-intensive and
intensive aquaculture. The division of aquaculture systems is based on the following criteria,
namely: feed, water management, stocking density, pond plot size, and production as shown
in Table 3.
Intensive aquaculture can produce maximum production but short operating time,
whereas traditional aquaculture has small production but long operating time (Boer 2010). In
general, the main issues in planning the development of aquaculture are appropriate
technology, minimize the environmental impact of aquaculture, consider the carrying
capacity of the environment, minimize disease, maximize production value, and reduce
poverty (Nautilus Consultants 2000).
The success of aquaculture is largely determined by the presence of various
components of aquaculture engineering factors. Poernomo (1992) outlines the requirements
of environmental engineering factors in aquaculture in Table 4.
According to Dahuri et al. (1996) in terms of aquaculture (ponds) factors that cause low
productivity, uncertainty of production results (including crop failure) are as follows:
1) Aquaculture technology skills (including broodstock selection, spawning, hatching
fertilization, larval rearing, brooding, enlargement, water quality management, feeding
management, genetics (breeding), fish health management and ponding techniques) of most
fish farmers are still low.
2) Competition for the use of space (aquatic land) between aquaculture and other development
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activities (settlement, industry, mining, etc.) generally always outweighs aquaculture.
3) Deteriorating water quality of resources for aquaculture, especially in densely populated or
high development intensity areas.
2.3 Silvofishery Pond System
Silvofishery ponds are a form of social forestry approach policy, which is an
environmentally friendly pond development model that combines forests/trees (sylvo) with
aquaculture (fishery). According to Balitbang Kehutanan (2013), the silvofishery pond system
is a mangrove forest rehabilitation technique in which the area is also cultivated for fisheries.
The silvofishery pattern is an integrated business concept between mangrove forests and
aquaculture, i.e. aquaculture in ponds is a prospective business alternative and in line with
blue economy principles. An integrated approach to the conservation and utilization of
mangrove forest resources provides an opportunity to maintain the condition of the forest
area remains good and in addition brackish water aquaculture can generate economic
benefits. The silvofishery concept offers an alternative technology that is applicable based on
the principle of sustainability (KKP 2013).
Mangrove forest management through a social forestry approach with a silvofishery
pond system has several benefits, namely increasing the percentage of mangrove plant
success above 80% with the types of fish cultivated are milkfish, shrimp, and crabs; the
development of farmers who cultivate ponds in the Forest Farmers Group (KTH) which
involves the Fisheries Service, the Agriculture Service, the local District Office and Perum
Perhutani itself; improving the standard of living of the community, especially those who are
members of the KTH; disturbances to the security and preservation of mangroves decreased;
and international recognition of the success of the brackish social forestry program (Perhutani
1993).
2.4 Sustainable Development Concept
Limited natural resources are a factor that limits humans to meet their increasingly
complex needs. The increase in the world's population certainly requires an efficient natural
resource utilization strategy so as not to sacrifice environmental factors so that the
sustainability of natural resources for future generations.
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can be sustained (Suryono 2006). According to Palunsu and Messmer (1997), sustainable
development is development that can meet current needs without compromising the ability of
future generations to meet their needs and does not exceed the carrying capacity of the
ecosystem (environment).
The goal of sustainable development according to Seragaldin (1996) is to always
improve the quality of human life on various aspects of life. Thus, the concept of sustainable
development is an effort to integrate three aspects of life (economic, social, and ecological) in
a synergistic relationship. The relationship is described as "A Triangle Framework" and
defined as economic, social, and environmental sustainability.
Based on this figure, it can be seen that the dimensions of sustainable development
include economic aspects that include sustainable growth and efficiency; social aspects
include justice, integration of social life, community participation and empowerment; while
ecological aspects include ecosystem integrity, natural resources, environmental carrying
capacity, and biodiversity. Sustainable development will be achieved if socio-cultural
development and environmental development have the same weight as economic
development.
2.5 Analysis Revenue
According to Nicholson (2002) farming is an economic activity aimed at producing
output (revenue) with physical inputs, labor, and capital in the production process. Farmers
will always look for ways to allocate inputs as efficiently as possible to obtain maximum
production because farmers are principled on how to get maximum profit (profit
maximization). On the other hand, when farmers are faced with limited costs in carrying out
their farming business, efforts to maximize profits can also be made by reducing production
costs to a minimum.
Total farm receipts are production results multiplied by the price per unit of production,
while total farm expenses are all values incurred in carrying out the production process. The
difference between revenue and expenditure is called income (Nicholson 2002).
2.6 Cost Analysis Benefits
Benefit-Cost Analysis (BCA) is an analysis used to determine the amount of profit or
loss, as well as the feasibility of a business activity. The main objective of BCA is to
determine projects or policies that are effective and efficient in the use of resources. This
analysis is based on additional costs and net benefits that form an additional flow of money,
then this measure will produce a Net Present Value (NPV), which is the ratio between the
sum of the benefits that have been discounted per the amount of costs that have been
discounted, so that t h e project will describe the efficient use of resources. Other criteria are
Benefit-Cost Ratio (BCR), Internal Rate of Return (IRR), and Payback Period (PP) (Gray
2008). Project evaluation is an assessment of an ongoing project, whether the project can be
continued (go project) or stopped (no go project), based on various aspects of the study
(Husnan and Suwarsono 1994). In evaluating an effective project must consider aspects that
are interrelated and jointly determines how profitable a particular investment is and considers
all these aspects (Gittinger 2008).
2.6.1 Financial Feasibility Analysis
Financial analysis is an analysis that is seen from the person who has a direct interest in
the benefits and costs of the business, namely the individual or entrepreneur (Gray et al.
2007). In Gray et al. (2007) the basis for the calculation of financial analysis is the price
using market prices for both the sources used for production and for the products of
production of the business, taxes are part of the benefits paid to government agencies, the
receipt of subsidies means a reduction in costs to be borne by business owners, investment
costs financed by own capital, and interest on domestic and foreign loans are project costs.
2.6.2 Economic Feasibility Analysis
Economic analysis is an analysis carried out to identify the benefits of all the resources
used in the project for the community or the whole economy regardless of who provides these
resources and who in the community receives the results of the project (Kadariah 2001). In
economic analysis, prices use shadow prices, which are prices that are adjusted in such a way
as to illustrate the true social value of these goods and services. The determination of the
shadow price according to Gray et al. (2007) is the social opportunity cost of each unit of
capital, which is equal to the social interest rate. Social opportunity cost is the benefit
obtained if the capital is invested in the project.
In addition to the shadow price, there are other basic criteria for calculating economic
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analysis such as taxes, which are transfers of project benefits that are handed over to the
government and used for the benefit of society as a whole. Subsidies are considered as
resources diverted from society for use in the project. Investment costs are considered as
project costs at the time of issuance. Interest on domestic loans is considered a social benefit
as it is not included as a cost, while interest on foreign loans that are tied and available only
for one specific project is accounted for as a project cost in the year of repayment (Gray et al.
2007). Logistic Regression Model
The analytical tool used to identify factors that influence decision making is the logistic
regression model. To identify the factors that allegedly influence decision making according
to Reijntjes et al. (1992) the method taken by a farming household depends on the
characteristics of the household concerned, such as the number of family members, age,
health conditions, abilities, wants, needs, farming experience, knowledge, and skills as well
as relationships between members household. According to Pattanayak et al. (2003) there are
five factors that influence the adoption of agricultural and forestry technologies, namely:
1) Farmers' preferences, explicitly the effects of farmers' preferences are difficult to
measure so an approach based on socio-demographic factors such as age, gender,
education and social status is used.
2) Resources endowment, used to measure the availability of r e s o u r c e s for
technology adoption to be implemented. Generally, resource endowment has a positive
correlation with technology adoption.
3) Market incentives are factors related to the low cost or high acceptance of technology
adoption. This factor is expected to increase acceptance so that it will have a positive
influence on technology adoption.
4) Biophysical factors are expected to influence production processes related to
agriculture and forestry. Generally, if biophysical conditions are low (such as the high
intensity of tidal flooding), it will be positively correlated with the willingness to accept
technology.
5) Risk and uncertainty, this factor shows the ignorance of the market and government
towards the policies made.
These factors were then adapted in the study as considerations to determine what variables
influence the decision of pond farmers in implementing silvofishery pond systems. The
factors used are farmer preferences, market incentives, and biophysical factors.
Logistic regression is one of the statistical models that can be used to analyze the
relationship pattern between a set of independent variables with a dependent variable of
categorical or qualitative type. The category of the dependent variable can consist of two
possible values (dichotomous), such as yes or no, success or failure, etc., or more than two
values (polychotomous), such as strongly disagree, disagree, agree, and strongly agree
(Rosadi 2011). In logistic regression analysis, modeling the probability of a particular event
from a category of response variables is done through a transformation from linear to logit
regression (Firdaus and Afendi 2008).
2.7 Previous Research
Many studies on mangrove ecosystems and silvofishery ponds have been conducted in
different places and at different times. Some of the results of these studies are used as
references in this study. Research on the role and benefits of mangrove ecosystem biological
resources have been conducted by Gunawan and Noorhidayah (2007). The results of research
by Gunawan et al. (2007) identified the role of silvofishery programs in contributing to the
income of surrounding communities and conserving mangrove forests. Halidah et al. (2007)
conducted research on the productivity of ponds in various mangrove closures, while a
comparative analysis of the results of fishery ponds inside and outside the mangrove area has
been done by Wisyanda (2013).
Research on financial and economic feasibility analysis has been conducted by
Margaretta (2013) on the economic analysis of white oyster mushroom farming and by
Renita (2013) analyzing the financial and economic development of natural tourism parks
according to the carrying capacity of the area. Mantau (2008) conducted research on the
investment feasibility of carp and tilapia fish farming in double floating net cages. The results
of previous research on mangrove ecosystems and silvofishery ponds and feasibility analysis
can be seen in Table 6 and Table 7.
T
Economic Feasibility Analysis
Economic analysis was conducted to determine whether the implementation of
silvofishery pond system is economically feasible by including social benefits and costs.
Feasibility indicators in economic analysis are the same as those used in financial analysis,
namely NPV, Net B/C, IRR and PP (Gray et al. 2007). Differences in economic and financial
analysis can be seen in Table 9.
The shadow price uses border prices for feed and fertilizer inputs because they are
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tradeable goods that can be traded internationally. The price used is the Cost Insurance and
Freight (CIF) price. The shadow price uses opportunity cost on labor input. Taxes are not
calculated in economic analysis Interest on loans is ignored in the cost calculation. Private
benefits and social benefits. The social benefits calculated are the benefits of mangroves as an
abrasion barrier and feeding ground. The value of abrasion resistance benefits is calculated
using the economic loss method and the value of feeding ground benefits is calculated using
the production cost approach.
The economic value of mangroves is assessed through identifying the benefits and
quantifying the value of benefits associated with mangrove forests. Economic value can be
divided into two, namely use value and non-use value. Use value includes direct use value,
indirect use value, and preferred use value. Non-use value consists of inheritance value and
existence value. In this study, the estimation of the value of mangrove benefits is limited to
direct use value in the form of fishery products and timber products, and indirect use value as
an abrasion barrier and feeding ground.
1. Direct Use Value
Direct use value is generated from the direct utilization of a resource, in this case the
mangrove forest. The direct use value is calculated from the types of utilization commonly
carried out by the community in Belawan Sicanang Village. This direct benefit value is
identified from the catch of fish, shrimp, crabs, and the potential value of mangrove wood.
The direct benefit value of mangrove forests from the productivity of fish, shrimp and
crabs can be obtained using the Productivity Method. The value is obtained by multiplying
the volume and selling price of fishery products. The potential value of mangrove timber is
obtained by using Analysis of Standing Volume on mangrove trees. Indirect Use Value
Indirect use values can be identified from the physical and biological benefits of
magrove forests. The physical benefits of mangrove forests are as a barrier to sea water
abrasion. The biological benefits are food supply areas for fish. Assessment of mangrove
forest silvofishery ponds as abrasion barrier obtained based on the approach of economic loss.
Identification of the amount of damage costs in this study focused on the type of direct-
tangible loss, where the loss value is calculated based on changes in flood losses due to
abrasion felt by the community before and after the implementation of silvofishery ponds
which are then deducted by the cost of planting and maintaining mangroves. Identifying
Factors Influencing Farmers to Select a Farming System
The analytical tool used to identify the factors that influence farmers in making
decisions on the selection of the type of pond is the logistic regression model approach.
Variables that are expected to influence the decision of farmers to choose the type of pond is
the level of formal education, the area of the pond, age, number of family dependents,
income, and length of business.
The equation function is formulated as follows (Juanda 2007):
..............(16)
where:
Y = Farmer's chance of making a decision (1 = implementing silvofishery farming system, 0 = not
implementing silvofishery farming system).
β0 = Intercept
β1 ...β5 = Parameter variable
PDDK = Formal education (years) LAT = Farm area (ha)
SK = Ownership status (owned/leased) LMB = Length of time farming (years)
PLTH = Participation in training
The hypotheses of the factors that are expected to influence farmers' decisions in
choosing the type of pond are as follows:
1) Formal Education (PDDK)
Formal education of farmers is expected to be positive. The higher the level of formal
education, the easier it will be to understand the prospects of pond type patterns compared to
low-educated farmers. Therefore, the higher the level of education, the easier it is to make the
selection of silvofishery ponds.
2) Farm Area (LAT)
The area of ponds owned is expected to be negative. The larger the area of ponds cultivated,
the smaller the possibility of mangrove cover so that it tends to prefer non-silvofishery ponds.
3) Ownership Status (SK)
Ownership status is expected to be positive. Privately owned farms will be more likely to
implement silvofishery farming systems than leased farms.
4) Length of Farming (LMB)
Length of farming experience is expected to be positive. The longer the experience in
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farming, the more it will encourage farmers to implement silvofishery farming systems.
5) Participation in Training (PLTH)
Participation in training is expected to be positive. The more often farmers attend training, the
more they can gain skills or expertise in implementing the technical aspects of silvofishery
farming systems.
5.1 Overview of Medan Sub-district Belawan
Astronomically, Medan Belawan Sub-district is located at the coordinate position of
03°.44'24"-03°.48'00" North latitude and 98°.37'48"-98°43'12" East Longitude with an
altitude of 2.5-37.3 meters above sea level with a land slope ranging from 0-4 percent. Medan
Belawan sub-district has a tropical climate with minimum temperatures ranging from 30.6ºC-
33.1°C and maximum temperatures ranging from 30.6°C-33.1°C. The air humidity in Medan
Belawan Sub-district averages 78-82 percent. Topographic conditions in Medan Belawan
Sub-district have a slope between 2.5-5.0 percent (Monograph of Medan Belawan Sub-
district 2013).
Medan Belawan area is divided into 6 urban villages, 161 RW and 432 RT with an area
of 21.82 km2 or 4.99 percent of the total area of Medan City. This research was conducted in
Belawan Sicanang Urban Village. The government area of Medan Belawan has a fairly large
area consisting of Belawan I to Bagan Deli villages. The largest area is Belawan Sicanang
Urban Village with an area of 15.10 km2 . Table 11 shows the details of the area of each
village in Medan Belawan Sub-district (Monography of Medan Belawan Sub-district 2013).
The map of the research location can be seen in Appendix 1.
The boundaries of Medan Belawan are as follows:
1. North : Malacca Strait
2. South : Medan Labuhan Sub-district
3. West : Hamparan Perak Sub-district
4. East Side : Percut Sei Tuan Subdistrict
5.1.1 Livelihood Population
There are 70 residents in Belawan Sicanang Village who work as pond farmers and are
categorized as small, medium and large entrepreneurs. Pond farmers have a proportion of
50% of the total entrepreneurs in Belawan Sicanang Village. Although fishpond farmers are
not the majority of livelihoods in Belawan Sicanang, the damage to the mangrove ecosystem
is large. The location where the research was conducted is Neighborhood 20 which has 40
pond farmers, which is 57.14% of the total number of pond farmers in Belawan Sicanang
Village.
5.2 Characteristics of Respondents
The research was conducted in Neighborhood 20 or more commonly referred to as
Canang Kering Village. Respondents in this study are pond farmers who apply silvofishery
system and do not apply silvofishery system. Some characteristics of respondents in this study
include gender, age, education level, land ownership status, farming experience, and land
area. Characteristics of respondents can be seen in Table 14.
Based on the table above, there were 39 male respondents (97.50%) and 1 female
respondent (2.50%). This considerable difference in the number of male and female
respondents shows that the number of jobs of pond farmers is mostly carried out by men in
Belawan Sicanang Village and is quite heavy to be carried out by women.
Respondents have varying age levels, from 20 to 60 years old. The majority of
respondents in the age range of 36-50 years were 20 respondents (50.00%), while the lowest
age range was 51-65 years as many as 9 respondents (22.50%). Respondents with an age
range of 20-35 were 11 respondents (27.50%). The data explain that in Belawan Sicanang
Village, the pond business is run by productive age.
The level of education of respondents will affect farmers' knowledge about the selection
of the type of pond system. Most of the respondents were as many as 14 respondents
(35.00%) whose education level was junior high school graduates. Respondents who did not
go to school were 3 respondents (7.50%), respondents with an education level of elementary
school graduates were 12 respondents (30.00%), the education level of high school graduates
was 10 respondents (25.00%) and those who graduated from college were 1 respondent
(2.50%). This low level of education is influenced by the mindset of respondents who still
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think that education is not the main thing and does not really affect the work that has been
done for generations.
Respondents interviewed generally had land with their own ownership status as many
as 30 people (75.00%), and leased ponds as many as 10 respondents (25.00%). Ownership of
ponds in Sicanang Village is mostly privately owned so that the ponds are cultivated by the
farmers themselves.
Farming experience is characterized by the length of time the respondents have been
farming. The number of respondents in the range of 5-15 years was 19 respondents (47.50%),
while farming experience in the range of 16- 15 years was the highest.
25 years as many as 15 respondents (37.50%), and in the range of 26-35 years as many as 6
respondents (15.00%). Farming is a cultivation business that has been carried out for
generations so that experience in cultivation has been gained since helping parents and
family.
The majority of respondents have a pond area with an area of 1000-5000 m2 as many as
39 respondents (97.50%). Based on respondents' data on the area of ponds in Sicanang
Village, the area of ponds owned by all respondents is almost the same because the economic
conditions of pond farmers in the research location are the same.
5.3 Potential Mangroves
Based on data obtained by the Department of Agriculture and Marine Affairs of Medan
City in the Documentation of Coastal Area Conditions of Medan City, it is known that the
area of mangroves in Medan Belawan Sub-district is 384.14 hectares. There are 12 species of
mangroves found in the Medan Belawan area, namely Rhizophora mucronata, Avicennia
marina, Sonneratia alba, Burguiera cylindrical, Excoearia, Rhizophora mucronata and
Avicennia marina. agalocha, Avicennia officinalis, Avicennia alba, Rizhophora stylosa,
Rizhophora apiculata, Lumnitetzera littorea, Bruguiera gymnorhiza, and Xylocarpus
granatum. Almost all true mangrove species are present in this location, ranging from fire
species (Avicennia spp.) which are generally the species in the front zonation in mangrove
forests, mangroves (Rhizophora spp.), and teruntum (Lumnitzera sp.) which are often found
in the back zonation.
The value of species diversity is realized through the Shannon-Wienner diversity index
which is a description of the vegetation structure in the form of assemblages of species in the
community. The diversity value is obtained based on data on the total number of individuals
of all species present at a location. According to Barbour et al. (1987), the value of the
Shannon Wienner diversity index (H) ranges from 0-7 with the criteria (a) a value of 0-2 is
low (b) a value of 2-3 is moderate and (c) a value of 3 or more is high. Diversity index value
data can be seen in Table 15.
The diversity index data obtained in the seedling, sapling and tree phases did not show
significant differences or small variations. When associated with the criteria compiled by
Barbour et al. (1987) that the diversity of mangrove vegetation is in the low group. The
smaller the diversity index value, the fewer the number of individuals of each type found.
In Medan Belawan for the tree phase, the highest number of species was in the buta-
buta wood species (Excoeceria agalocha) with 89 individuals and the lowest in the mangrove
species (Rhizophora apiculata) and teruntum (Lumnitzera littorea) with 1 individual. This
huge variation is thought to cause the low diversity index obtained (Department of
Agriculture and Marine Affairs of Medan City 2013).
The Shannon Wienner diversity index value data can also describe the actual condition
of the mangrove forest ecosystem and its need for rehabilitation programs. Magurran (1983)
in the Department of Agriculture and Marine Affairs of Medan City (2013) provides criteria
for the value of the Shannon Wienner diversity index as follows:
1. Diversity index value < 1.50; mangrove ecosystem condition is severely damaged and
absolutely must be rehabilitated immediately.
2. Diversity index value 1.50 < IK < 3.00; mangrove ecosystem condition is lightly damaged
and rehabilitation activities should be carried out.
3. Diversity index value > 3.00; ma n gr o v e forest ecosystem condition is good, mangrove
flora richness is maintained, mangrove species diversity is quite high and mangrove forest
rehabilitation activities are not required. Based on these criteria, it can be described that in
Medan
Belawan has a diversity index value of 1.70 which indicates that the mangrove forest
ecosystem in this location is in a mildly damaged condition and rehabilitation activities
should be carried out (Table 15). The physical condition of the mangrove forest can also be
assessed from the aspect of vegetation density. The greater the species density value, the
better the condition of a forest, and conversely the lower the species density value, the more
urgent the need for rehabilitation of the mangrove ecosystem.
The Ministry of Environment (MOE) of the Republic of Indonesia through Ministerial
Decree No. 201 of 2004 concerning standard criteria for mangrove damage and guidelines for
monitoring mangrove damage, has issued a criterion for the level of mangrove forest damage
17
based on the value of tree density per hectare, the standard criteria are divided into:
1. Very Good (Very Dense) if there are > 1500 trees per hectare.
2. Good (Medium) if there are 1000-1500 trees per hectare.
3. Damaged (Rare) if there are < 1000 trees per hectare.
The measurement results of tree, sapling, and seedling density values in Medan Belawan
Sub-district can be seen in Table 16 below.
Based on the value of tree density per hectare obtained from the criteria for the level of
mangrove forest damage from the Ministry of Environment, it appears that the condition of
mangrove forests in Medan Belawan Sub-district is included in the damaged group with a
sparse tree density (Table 16). The high and low values of mangrove density of seedling and
sapling classes are very important in determining the stability of the mangrove forest
ecosystem. In mangrove forests with low density values of seedling and sapling classes
indicate that the mangrove forest is experiencing very severe disturbances. The criteria in
Table 15 and Table 16 prove that the condition of mangroves in Medan Belawan has been
damaged and needs rehabilitation.
1.1 Condition of Aquaculture at the Site Research
Belawan Sicanang Sub-district is the largest pond area in Medan Belawan Sub-district
with 310 hectares of productive pond land (Department of Agriculture and Marine Affairs of
Medan City 2013). The majority of aquaculture in Belawan Sicanang is tiger shrimp, tilapia
and crab farming. There are two aquaculture systems applied in Canang Kering Village,
namely silvofishery ponds and non-silvofishery ponds. Both systems are traditional types of
ponds. The difference between silvofishery ponds and non-silvofishery ponds in the research
location can be seen in Figure 4.
When opening non-silvofishery ponds, farmers converted mangrove forests into fishery
commodity ponds, causing damage and loss of ecological functions of the mangrove
ecosystem. The Suka Karya 6 Farmer Group recognized the degradation of the environment
and applied to the Forestry Department for training in the establishment of silvofishery ponds
through demonstration ponds. In the silvofishery pond system, farmers who had previously
converted mangrove forests into ponds were trained to create silvofishery ponds.
Non-silvofishery farmers are encouraged to replant mangrove forests around their ponds.
Pond farmers were given counseling on the benefits of silvofishery systems that can be a form
of sustainable mangrove utilization, namely cultivating pond fisheries that depend on the
preservation of mangroves as a feeding ground and nursery ground, where if mangroves are
disturbed then pond fisheries are also disturbed. This system is expected to preserve
mangroves while increasing the productivity of aquaculture ponds.
The silvofishery pond system is technically similar to non-silvofishery ponds, but the
silvofishery pattern combines forestry and fishery activities in a pond area, which is divided
into effective land for raising shrimp or fish and land planted with mangrove trees.
Silvofishery developed in Indonesia has two patterns, namely empang ditit or better known as
intercropping ponds, and komplangan. In the research location, the pattern applied is trench
ponds.
The trench pond pattern is a commonly developed silvofishery model. It can be applied
to an area of former ponds that will be rehabilitated by utilizing the pond yard (center) for
mangrove planting, while the ditch is left as before for fish cultivation (Bengen 2000). In the
trench pond system, ponds used for aquaculture are made in the form of a trench surrounding
the mangrove forest, with a recommended area of 20 percent trench and 80 percent
mangrove. The pond area ranges from 0.3-3 hectares with a planting distance of 1×1 meter to
3×3 meters between individual mangroves (Perhutani 1993).
The practice of using the trench pond system pattern carried out in Canang Kering
Village is given leeway by the Forestry Service where the land is planted with mangroves
covering 30 percent of the pond area, this is because pond farmers consider the wider the
mangrove area will reduce the economic value of pond products. This condition is expected
to continue to increase until it reaches the ideal conditions set by Perhutani but the constraints
that occur is no further supervision of the relevant agencies so that the extent of mangrove
ecosystems in silvofishery ponds in the study area has not increased. The area of mangrove
ecosystems is not in accordance with the conditions ideal has implications for the ecological
benefits perceived by the pond to be less than optimal.
Another constraint to the implementation of silvofishery ponds in Canang Kering
Village is the loss of revenue during the first three years. The maintenance of newly planted
mangroves takes three years before they can be used as aquaculture ponds, if aquaculture
activities are carried out from the first year, it will hamper mangrove growth and can lead to
failure in the creation of silvofishery ponds. The absence of alternative sources of income is
the reason why not all farmers want to implement silvofishery pond system. Farmers who
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have implemented silvofishery farming systems have more than one pond so they still have
other sources of income when one of their ponds is converted into a silvofishery pond. The
transition from non-silvofishery ponds to silvofishery ponds is done in stages. The operational
differences between the two farming systems can be seen in Table 17.
Based on Table 17, it can be seen that the intensity of the harvest season in the
silvofishery pond system is three times a year, while in non-silvofishery ponds only twice a
year. In aquaculture business is not always the same from one season to the next. This is
influenced by various factors including land conditions, water, weather, and seeds and fishery
commodity seeds. Non-silvofishery ponds only experience two harvest seasons due to harvest
failure due to pond rupture during tidal floods. Tidal flooding occurs because mangrove
ecosystems in coastal areas are damaged. The use of inputs such as feed, fertilizer, and
medicine is lower in silvofishery ponds, this is due to the presence of silvofishery ponds.
ecological benefits from the presence of mangroves around the pond area. The use of lower
inputs is one of the advantages of silvofishery farming over non-silvofishery farming.
1.2 Comparative Analysis of Silvofishery and Pond Income
Non-silvofishery
Coastal communities have the majority of livelihoods as fishermen and pond farmers in
aquaculture. In line with regional autonomy, the accelerated development of aquaculture is
directed to create superior commodities through the development of aquaculture systems by
involving business actors in the region and continuous guidance by prioritizing the concept of
empowerment and participation of aquaculture communities. The potential of aquaculture
ponds in Medan City is presented in Table 18.
Income analysis was conducted on both pond systems in Canang Kering Village,
namely silvofishery ponds and non-silvofishery ponds. Income analysis is a comparison of the
average income of silvofishery pond farmers and non-silvofishery pond farmers per unit
hectare per year. Income on the farmer is a direct benefit of aquaculture. Farmers who apply
silvofishery pond system has a different level of income with non-silvofishery pond farmers.
Revenue is the sum of the sales revenue of shrimp, fish and crabs for a year. Based on Table
19, it can be seen that in silvofishery ponds more fishery products are obtained than in non-
silvofishery ponds. Output on silvofishery ponds is more because there are three harvest
seasons in a year, the difference in the percentage of output per year of the two pond systems
shows that the output of silvofishery ponds is 45% higher than non-silvofishery ponds
(Appendix 2). In terms of revenue per harvest, the output of silvofishery farms is also higher
than non-silvofishery farms. Receipts on silvofishery farms are much greater due to increased
productivity of aquaculture supported by the presence of mangroves, this is because
mangroves act as organic detritus which is a natural food source for all biota (Bengen 2002).
Silvofishery farmers who do crab cultivation less than in non-silvofishery ponds, this is
because silvofishery farmers prefer to cultivate shrimp commodities because it is considered
capable of adapting to mangrove habitats, fast growing, and relatively resistant to unfavorable
conditions so as to increase the production efficiency of silvofishery ponds (Appendix 2).
The difference in the percentage of expenditure per year shows that expenditure on
silvofishery ponds is 17% higher than non-silvofishery ponds, this is due to three harvest
seasons in a year which results in the use of more inputs so that the variable costs incurred are
higher and there are also additional maintenance costs mangrove (Appendix 2). When viewed
from the cost per growing season inputs used in silvofishery ponds are lower, the percentage
difference in expenditure of silvofishery ponds per growing season is 3% lower than non-
silvofishery ponds (Appendix 2). In Appendix 2 it can be seen that the percentage difference
in feeding quantity on silvofishery ponds is reduced by 9% compared to non-silvofishery
ponds because they get additional ecological benefits from mangroves as a feeding ground.
There are some respondents who continue to use additional feed other than natural feed
produced by mangroves because pond farmers are still accustomed to using additional feed to
increase fisheries productivity and mangrove feeding ground function has not been able to
cover all the feed needs of aquaculture pond commodities.
Although the cost of silvofishery ponds higher but this is offset by a much greater
revenue so that the comparison of income shows that the income of silvofishery pond farmers
greater than non-silvofishery pond farmers. Based on the value of the R / C ratio obtained by
both farming systems have a value of more than one so that both farming systems are
profitable. The R / C ratio of silvofishery ponds is greater than the R / C ratio of non-
silvofishery ponds, this indicates that silvofishery ponds are more profitable to cultivate than
non-silvofishery ponds. Details of the income analysis calculation can be seen in Appendix 2.
1.3 Financial and Economic Feasibility Analysis of Ponds Silvofishery
The implementation of a silvofishery pond system will provide ecological benefits in
the long term so it is necessary to conduct a feasibility analysis to see if the silvofishery pond
system is feasible, both financially and economically. Aspects that need to be considered in
the feasibility study are divided into two groups: financial aspects and non-financial aspects.
21
Feasibility analysis uses cash flow to determine the amount of benefits and costs incurred
over a certain period.
1.3.1 Analysis of Non-financial Aspects of Silvofishery Farms
Non-financial aspects that need to be discussed include technical, management, social,
environmental, market and economic aspects. This is done to determine the effectiveness of a
business by considering aspects that simultaneously determine how the profits obtained from
the business being run.
Technical Aspects
Technical analysis includes analysis of inputs and outputs in the form of goods and
services needed and produced in a business. The silvofishery pond business requires the
availability of inputs in the form of construction tools for making ponds, mangrove seeds,
fish seeds to be cultivated, fish feed, and labor.
1. Pond Creation
Ponds are an important part of the production facilities in the pond business. The
standard that must be met by farmers in making ponds is a pond with a size of 100×100
meters. Each pond unit must have a sluice gate and a single plot. The sluice gate is used as a
means of irrigating the pond. The single plot is used for the growth of fish fry or shrimp fry.
Farmers initially converted mangrove forests into non-silvofishery ponds which were
then replanted with mangroves to become silvofishery ponds. The total area of silvofishery
ponds in Canang Kering Village is 29 hectares with an average pond area of two hectares per
farmer. Each pond generally has a guard house and a Fisheries Business License (SIUP).
Based on the results of the respondent questionnaire, the capital required for pond
construction averaged IDR 33,357,142.86/ha.
2. Mangrove Seeds
Mangrove seeds are used as plants that support and complement silvofishery ponds.
Mangrove plants in these ponds have many ecological functions such as nursery ground and
feeding ground thus increasing the productivity of the ponds.
The price of mangrove seeds is Rp 500.00 per piece. For one pond, farmers generally
buy 1100 seedlings which are planted in seedling ponds. After one year the seedlings can be
moved to the pond, then for three years the mangrove seedlings are maintained until they
grow and become a habitat for aquaculture commodities.
3. Seeds
Seeds are one of the important inputs in silvofishery ponds. The fishery commodities
cultivated are tiger shrimp, tilapia and crabs. The seeds used when first introduced into the
ponds are tilapia fingerlings that are 2 inches in size, shrimp fry that are 12-15 pl (post
larvae), and crabs that weigh 3-5 grams. Tilapia fry w e r e obtained from natural catches,
shrimp fry were obtained from hatcheries and cobblers, while crab fry were obtained from
agents who came to the pond location.
The seed price obtained by farmers for tilapia seeds is Rp 250 per fish. Each plot of
pond is seeded with 1,500 fish. The price of seeds obtained by farmers for tiger shrimp seeds
is IDR 50.00 per head. Each plot of pond is seeded with 10,000 shrimp. The price of seeds
obtained by farmers for one kilogram of crab seeds is IDR 30,000 per kilogram. Each pond
was stocked with 20 kilograms of crab seed.
Farmers admit that they often have difficulty obtaining seeds because the number of
seed traders is limited in meeting the increasing demand for seeds. The availability of a
limited number of seed traders causes seed prices to increase.
4. Feed
Feed purchase is an optional operational cost in silvofishery pond management. Some
farmers continue to use supplementary feed in addition to the natural feed obtained from
mangroves because it is considered to increase productivity more quickly. The type of feed
used to feed tilapia cultured in ponds is fish pellets. Tilapia are fed with a frequency of pellets
twice a day a day. The type of feed used to feed the crabs is ikan rucah with a frequency of
once a day. Tilapia were fed with pellets twice a day. The type of feed used to feed shrimp is
artificial concentrate feed, which is global brand feed. Shrimp are fed with a frequency of
pellets twice a day.
This supplementary feeding is given one month after stocking until the harvest. The
feed is obtained by farmers at a price of Rp 10,000 per kilogram. Each pond plot generally
uses 25 kilograms.
5. Labor
The labor used comes from outside the family. 1-3 male laborers are needed to manage
the pond during the harvest season. The number of working days for farmers to carry out
23
harvesting activities is 5 hours, the wage of labor outside the family is IDR 85,000 per
working person day (HOK).
The number of working days for harvesting generally takes place in one day, so that in
a period of one year consisting of three harvest seasons with three people outside the family
there are 9 HOK. Cultivation activities other than during the harvest season are relatively
simple so that they can be carried out by farmers themselves.
Social and Management Aspects
Management aspects of silvofishery ponds consist of organizational structure and
responsibilities in business activities. The organization contained in this business is a farmer
group. The role of farmer groups in the research location is as a cooperative unit and as a
facilitator that connects farmers with the government when there is assistance, training, and
other activities. Farmer groups are assisted by the Department of Agriculture and Marine
Affairs.
The social aspect analyzes the social implications of silvofishery farming. This pond
business has a positive impact, namely opening up employment opportunities for people
living in Belawan Sicanang Village. With the pond business, people around the location get
job opportunities.
Environmental Aspects
Silvofishery ponds have a positive impact on the environment, this is due to waste from
the use of inorganic chemicals in ponds such as drugs used as feed for fish. The presence of
mangroves can also absorb waste and as a biofilter to improve water quality, in addition
mangroves also have an ecological function as a nutrient provider for aquatic biota, spawning
and nursery for various biota, erosion prevention that reduces the potential for pond rupture.
Market Aspects
The market aspect analyzes the demand, supply, price, marketing and sales forecasts of
farmed fish, market structure and competition of silvofishery farming activities.
1. Inquiry
The demand for fishery products in Medan is quite large, this can be seen from the
amount of fish consumption by the people of North Sumatra which reached 38.95 percent of
overall food consumption. This is higher than the national average of 35.14 percent (BPS
North Sumatra Province 2013). Shrimp, fish, and crabs are the types that are much favored by
the community so that the demand is quite high, but along with the high demand for fish is
still not balanced with the production of cultured fish that often experience crop failure.
2. Offer
The total supply of fish produced by silvofishery farms was obtained based on the
average production in the respondents' questionnaires. The average production of tilapia
reached 407.14 kg/ha/year, the average production of shrimp reached 184.29 kg/ha/year, and
the average production of crabs reached 30 kg/ha/year.
3. Price
Fish prices for each type and size at the farm level vary. Based on the results of the
respondents' questionnaires, the average price received by farmers was silvofishery ponds for
tilapia production amounted to Rp 8,075.00 per kg, the price received by farmers for crab
production amounted to Rp 38,400.00 and shrimp amounted to Rp 67,550.00 per kg. The
general market price for tilapia production is Rp 15,000 per kg, crab is Rp 50,000 per kg, and
shrimp is Rp 60,000 per kg, but this is also influenced by the size and weight of the fishery
commodities.
4. Marketing
Marketing analysis in this business is to analyze the fish products sold by farmers and
how farmers distribute their products. For each type of aquaculture product, the size of fish
produced varies according to market needs. Consumer demand for aquaculture products
comes from various regions in North Sumatra Province. Pond farmers distribute their fish to
intermediary traders. Fish harvested by farmers are usually purchased by intermediary traders
to be marketed to the regions.
5. Business Competition
Competitors of silvofishery ponds that need to be considered are non-silvofishery
ponds. Silvofishery ponds have advantages in terms of higher yields and can be categorized as
organic products, lower input use resulting in lower costs per growing season, and additional
25
ecological benefits from the presence of mangroves such as reduced risk of crop failure due
to pond rupture.
1.3.2 Financial and Economic Feasibility Analysis of Silvofishery Farms
To analyze the financial aspects, it is necessary to analyze the cost and benefit
components of silvofishery ponds. These cost and benefit components are used to estimate the
value of Net Present Value (NPV), Internal Rate of Return (IRR), Benefit Cost Ratio (BCR),
and Payback Period (PP) both financially and economically. The feasibility analysis looked
at the entire silvofishery ponds in Canang Kering Village with a total area of 29 hectares.
There are some differences in the financial and economic feasibility analysis, in the
fixed cost component of the financial analysis shows the cost of land tax silvofishery ponds
while the economic analysis of tax costs are not calculated because it is a transfer of benefits
from silvofishery ponds submitted to the government for the benefit of the whole community.
In the variable cost component, there are differences in the price of feed and fertilizer
i n p u t s , financially the price of feed and fertilizer used is the market price while
economically using the shadow price (border price) because feed and fertilizer can be traded
internationally (tradeable inputs). Calculation of border price of feed can be seen in Table 20
and border price of fertilizer can be seen in Table 21.
Labor in the economic analysis is included in the component of social benefits and
variable costs, this is due to the social benefits of labor absorption from silvofishery ponds.
The value of labor absorption is obtained through wages received by workers who get the
opportunity to work from silvofishery farming activities, while labor in the variable cost
component is a shadow price obtained from the opportunity cost of work other than pond
farmers. The benefit component of silvofishery ponds can be divided into private benefits and
social benefits.
1. Private Benefits
The financial benefit component of silvofishery ponds is a private benefit obtained from
the sale of pond products and mangrove wood products. The value of the benefits of
silvofishery pond fishery is Rp 489,764,905.00 per year. Details of the calculation of fishery
products as presented in Table 22.
The useful value of wood products of silvofishery ponds is calculated based on the
potential of wood obtained by analyzing the volume of the stand. Department of Forestry
(2012) showed that the location of silvofishery ponds mangrove ecosystem dominated by
Rhizophora spp. with an average diameter of 0.14 meters, an average height of 5.3 meters,
and the average density of mangrove trees is 529 trees per hectare. Based on these data, the
potential of mangrove wood volume is 86.28 m3 per hectare.
The economic value of mangrove wood potential in Belawan Sicanang Village is Rp
375,298,235.00 / year. This value is obtained from multiplying the volume of mangrove
wood with the price of mangrove wood at the research site per cubic meter of Rp 150,000.00.
Costs incurred for mangrove wood collection obtained from the results of LPP Mangrove
research (2000) which is around 30% of the economic value of potential timber per hectare.
The net economic value of mangrove timber potential was obtained by reducing the
economic value by the cost of extraction, which amounted to IDR 262,708,765.00/year
(Table 23).
According to the Ministry of Forestry (2012) logging that can be done for silvofishery
ponds with an ideal proportion of mangrove forests and ponds 80:20 is logging with an area
range of 25% - 50% of the total area. The total area of silvofishery ponds at the research site
is 29 hectares with a ratio of land for the purposes of ponds and mangrove area is 70:30 with
a total economic value of mangrove wood amounting to Rp 78,812,629.00. Logging of
mangrove wood at the research site is done with a system of logging needs, which is allowed
when there is a sudden need (eg school fees, marriage, or childbirth) with a maximum area
cut down 25% of the total area of mangroves in the pond. Based on these calculations
obtained economic value of mangrove wood amounted to Rp 19,703,157.25 / year (Table
23).
2. Social Benefits
One of the differences between financial and economic feasibility analysis is that the
benefits received by silvofishery farmers include private benefits and social benefits. Private
benefits received by silvofishery farmers are the same as the benefits in the financial
feasibility analysis. Social benefits are benefits that are felt not only by business actors but
also by the whole community. The social benefits received by pond farmers can be estimated
from the physical function of mangroves as an abrasion barrier, the biological function of
mangroves as a feeding ground, and labor absorption.
The economic value of mangrove forests as an abrasion barrier is obtained using the
economic loss approach. The benefits of mangrove forests as abrasion barrier can be replaced
with an estimate of economic losses due to abrasion before and after the implementation of
27
silvofishery pond system, then the value obtained is deducted by the cost of planting and
maintaining mangroves. To determine the economic value of the benefits of mangroves as an
abrasion barrier, the value of losses due to inundation that occurs during flood tides is
estimated. The calculation of costs is focused according to the land use that is inundated by
sea water, including residential areas, rice fields and community aquaculture, and road
networks. The damage costs used were assumed to be when it was severely damaged by tidal
flooding.
The sea level rise that occurs during normal tide conditions is as high as 0.8 meters.
The frequency of occurrence of this condition is quite large, which can reach around 432
hours per year, or during the East season and transitional season (March-November). Tidal
flooding is expected to inundate the coastal area, reaching an inundation area of 240.02
hectares or 11 percent of the total area of Medan Belawan Sub-district.
Canang Kering Village is located in Neighborhood 20 in Belawan Sicanang Urban
Village which is also affected by tidal flooding. The area of Neighborhood 20 is 45.50
hectares or 3.01 percent of the entire area of Belawan Sicanang Urban Village. The total area
inundated during tidal flooding in the Canang Kering Village area was obtained from the
Belawan Sicanang Urban Village Office (2013). The estimated value of losses in each land
use due to abrasion can be seen in Table 24.
The Head of Neighborhood 20 revealed that the impacts that occurred in Canang
Kering Village were classified as minor damage, due to the location of the village which is
not directly adjacent to the beach. According to the results of an interview with a key person
who is an environmental observer, the value of losses due to tidal flooding is estimated at
33.33% of the losses experienced by coastal areas, so the estimated economic loss due to tidal
flooding in Canang Kering Village is IDR 1,621,435,562.00/year (Table 25). The silvofishery
pond system was implemented in Canang Kering Village with a total area of 29 hectares of
ponds over the past four years. Key person estimates the change in losses incurred due to tidal
flooding after the implementation of silvofishery pond system is 10%. The value of the
benefits of silvofishery ponds as an abrasion barrier is worth Rp 49,250,669.10 per year.
The value of mangrove forests as a feeding ground was estimated by the difference
between the feed cost of silvofishery ponds and the feed cost of non-silvofishery ponds. The
value of the benefits of silvofishery ponds as feeding ground is worth Rp 1,989,048.81 per
year. The calculation of the economic value of mangrove forests as a feeding ground can be
seen in Table 26.
Table 26 Economic value of mangrove forest as feeding ground
The value of social benefits of labor absorption is obtained from the difference between
the wages of silvofishery farm labor and the opportunity cost of other jobs. Silvofishery ponds
use outside labor only in harvesting activities, which requires an average of three workers
calculated based on the number of man-days (HOK). In the research location, harvesting
activities are carried out for one day, in a year there are three harvest seasons so that for one
hectare of pond there are 9 HOK in a year. The number of available labor is assumed from
the number of households in Canang Kering Village. Calculation of the percentage of labor
absorption from silvofishery ponds is presented in Table 27.
The opportunity cost approach is done by calculating the wages of employment
opportunities other than as silvofishery pond labor. In this study, it is assumed that other
alternative jobs are as laborers, because labor is the most common livelihood of the Canang
Kering Village community. Labor wages are Rp 35,000 per person day of work (HOK). The
value of social benefits of silvofishery ponds as labor absorption is Rp 11,745,000.00 per
year. Calculation of the value of labor absorption can be seen in Table 28.
According to Gittinger (1986), Net Present Value (NPV) is the present value of the
flow of benefits generated by an investment. Based on NPV criteria, a project or business is
feasible to implement if the NPV is greater than zero. In the calculations performed, the NPV
value of silvofishery ponds is Rp 2,555,462,368.68 financially and Rp 3,187,956,928.44
economically. NPV value indicates that the silvofishery pond business is feasible to
implement financially and economically.
Benefit Cost Ratio (BCR)
The value of the Benefit Cost Ratio (BCR) is a comparison between the discounted net
benefits that have a positive value with discounted net benefits that have a negative value.
Based on the results of the BCR calculation obtained by, indicating that in principle
silvofishery ponds are feasible to implement financially and economically because the BCR
value is greater than one. BCR value of silvofishery ponds financially is 12.31; meaning that
each cost incurred by one rupiah per hectare per year will generate additional income in the
form of net profit of 12.31 rupiah per hectare per year.
The BCR value of silvofishery ponds economically is 15.95; meaning that every cost
incurred by one rupiah per hectare per year will be generates additional income in the form of
a net profit of 15.95 rupiah per hectare per year.
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Internal Rate of Return (IRR)
Internal Rate of Return (IRR) illustrates how much profit or excess income will be
obtained each year from this business. If the IRR value obtained is less than the deposit
interest rate used is 7%, the money used as capital should be saved or used for other
businesses because it will get a more favorable return, or in other words, the business is less
feasible in terms of return on capital. In this case, based on the calculations made IRR value
of silvofishery ponds is 65% financially and 76% economically, which indicates that the farm
is feasible to be cultivated because the rate of return on capital is higher than the prevailing
interest rate.
Payback Period (PP)
Payback Period is calculated to determine how long the investment value can be
returned. The payback period value is obtained from the comparison of the investment value
with the discounted net benefits. Based on the calculation results, the PP value for
silvofishery pond investment is 3 years 8 months financially and 3 years 6 months
economically.
1.4 Factors Influencing Pond Farmers' Decision to Implement a Pond System Silvofishery
In general, Medan Belawan Sub-district is located 3 meters above sea level, thus from a
geographical point of view it is included in the lowland zone (less than 100 meters below sea
level). According to the urban, rural regional planning field (1980) that urban cultivation
activities can be developed at a regional altitude of < 1000 meters below sea level. Based on
these altitude criteria, Medan Belawan Sub-district is very suitable for the development of
aquaculture areas.
In line with regional autonomy, the acceleration of aquaculture development is directed
to create superior commodities through the development of aquaculture systems by involving
business actors in the region and continuous guidance by prioritizing sustainability aspects.
Potential pond land in Medan City area is 2,000 hectares with a production of 1,249.5 tons.
Pond land in Medan Belawan Sub-district is 310 hectares (Department of Fisheries and
Marine of Medan City 2013). Aspects that need to be done in order to maintain the
sustainability of fish and shrimp farming, among others:
1. Planting mangroves around ponds so that mangroves can function as biofilters to improve
water quality. The remains of mangrove leaves that have decomposed are also needed by
shrimp and fish for life and growth.
2. Improve supervision and enforcement of environmentally unfriendly cultivation activities.
3. Conduct regular training to fish farming communities on sustainable aquaculture concepts.
The main problem of pressure on mangrove habitats stems from the human desire to
convert mangrove forest areas into areas of commercial activities, agriculture, especially for
the opening of ponds. According to Bengen (2000), widespread destruction of mangrove
forests for pond clearing will result in the loss of biodiversity and other resources and
ecological functions of the ecosystem.
According to Triyanto et al. (2012), silvofishery cultivation within mangrove areas
allows for aquaculture without the need to convert mangrove areas. This alternative
management is expected to increase the economic value of mangrove forests without
threatening their ecological functions. Aquaculture of fishery products by applying
silvofishery pond system can produce better productivity seen from the harvest that was
originally twice a year can be increased to three times a year. According to Wahana (2013)
some of the benefits that can be obtained by applying silvofishery, namely:
1. The construction of the bund will be strong because it will be held by mangrove roots from
mangrove trees planted along the pond bund.
2. The results of research by Martosubroto and Naamin (1979) in Wahana (2013) show that
there is a significant relationship between mangrove area and aquaculture production where
the increase in mangrove area will increase aquaculture production.
3. One of the ecological functions of mangrove ecosystems has been used as wastewater
treatment since 1990. Results from a field study in Futian National Natural Resource
Conservation, China indicated that increasing pollutant concentrations in mangrove areas did
not lead to detectable damage to mangrove plants.
4. Increased income of pond farmers due to increased production of fish catches.
5. Prevent coastal erosion and seawater intrusion inland so that settlements and freshwater
sources can be maintained.
6. Mangroves will reduce the impact of natural disasters such as storms and tidal waves so that
the risk of farming activities being exposed will be reduced.
T h e case study of factors influencing the decision of pond farmers to implement
silvofishery farming systems uses the independent variables of formal education, pond area,
ownership status, length of farming, and participation in training. The dependent variable
used has two possibilities. Respondents who have applied the silvofishery pond system is
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given a value of 1 (Z=1) and for respondents who do not apply the silvofishery pond system
is given a value of 0 (Z=0). The following data processing results Table 30.
Based on the results of the logistic regression analysis obtained a significant value in
the Omnimbus test of 0.000. The value is smaller than the real level used is 10% and 15%
(0.000 < 0.10) and (0.000 < 0.15), meaning that the independent variables used affect the
decision of farmers to choose the pond system. From the analysis obtained Cox and Snell R
Square value of 0.647 and Nagelkerke R Square of 0.891. Nagelkerke R Square value is
greater than Cox and Snell R Square indicates the ability of the five independent variables in
explaining the variance of the decision of farmers in the selection of pond systems by 89.1%
and there are 10.9% other factors outside the model that explain the dependent variable.
The Significant value in the Hosmer and Lomeshow Test obtained is 0.983. This value
is greater than the real level used, namely 10% and 15% (0.983> 0.10) and (0.983> 0.15),
meaning that the model made is acceptable and hypothesis testing can be done. So that the
overall percentage value in the classification table obtained is 95%. This value shows that of
the 40 data there are 38 data that are correctly classified. This shows that the resulting model
is good. Details of the logistic regression results can be seen in Appendix 5.
Based on Table 33, it can be seen that of the five independent variables that allegedly
affect the decision of farmers to implement the pond system, there are three variables that are
significant. Variables that significantly influence the decision of these farmers are formal
education, land area, and participation in training. Based on whether or not the influence of a
variable is seen from the significant value in Table 33 which is smaller than the real level
used is 10% and 15%.
Formal education variable has a significant value of 0.141. This value means that
education has a significant effect on the likelihood of the implementation of silvofishery pond
system by farmers at a real level of 15% (0.141 <0.15). The coefficient obtained positive sign
(1.318) and the value of Exp (β) or odds ratio obtained amounted to 3.735. This indicates that
the higher the level of formal education of a farmer then the chances of farmers to apply
silvofishery farming system is greater 3.735 times than not to apply silvofishery farming
system. In general Formal education level will give the farmer the ability to understand the
relationship between environmental quality and pond productivity.
Variable farm area has a significant value of 0.099. This value means that the area of
the farm has a real effect on the chances of the implementation of silvofishery farming system
by farmers at a real level of 10% (0.099 <0.10). The coefficient obtained positive sign (1.974)
and the value of Exp (β) or odds ratio obtained amounted to 7.197. This means that if the area
of the pond increases by one hectare, the chances of farmers to apply silvofishery pond
system is 7.197 times greater than not to apply silvofishery pond system. This is because the
area of the farm will affect the level of production efficiency of silvofishery ponds The
variable of participation in training has a significant value of 0.131. This value means that
participation in training has a real effect on the chances of the implementation of silvofishery
farming system by farmers at a real level of 15% (0.131 <0.15). The coefficient of the results
obtained positive sign (2.747) and the value of Exp (β) or odds ratio obtained amounted to
0.064. This means that if participation in training increases by one experience, the chances
of farmers to implement silvofishery farming system is 0.064 times greater than not to
implement silvofishery farming system. Through participation in training, farmers can gain
skills or expertise in implementing the technical aspects of silvofishery farming systems.
Ownership status variable has a significant value of 0.563. This value means that
ownership status has no significant effect on the chances of farmers implementing
silvofishery pond system. This is because the research location of land ownership does not
affect the efficiency of pond production.
Variable length of farming has a significant value of 0.904. This value means that the
length of farming does not significantly affect the chances of farmers implementing
silvofishery farming system. This is because the length of time a person farms does not affect
the decision to implement a silvofishery farming system. Farmers who have The experience
of farming with the same system that has been used for generations tends to make it more
difficult to take the risk of implementing a new farming system.
1.5 Silvofishery as an Alternative Form of Ecosystem Utilization
Mangroves Sustainable
Based on the feasibility analysis, it can be seen that the silvofishery pond system is
feasible both financially and economically so that it can be an indicator of the achievement of
economic aspects. Environmental aspects are achieved through the implementation of
silvofishery pond system as an effort to rehabilitate mangrove forests that have been damaged
and the additional ecological benefits of mangroves in the pond area as an abrasion barrier
and feeding ground. The social aspect is seen from the silvofishery pond system which is a
job and source of income for the community around the mangrove area. This shows that the
silvofishery pond system has met the three pillars of sustainability and can be an alternative to
sustainable use of mangrove ecosystems. In realizing sustainable use, synergism between
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government, community and business actors is needed to support the ecological and
economic functions of the area.
In addition to its economic and ecological benefits, silvofishery farming also has some
disadvantages. One of the disadvantages of silvofishery ponds is that they require higher
investment costs for the purchase of mangrove seedlings. The results of aquaculture obtained
in silvofishery ponds are less because cultivation cannot be done intensively. This is due to
the density of biota to be cultivated must be in accordance with the existing environmental
power and environmental conditions are relatively more natural so that the threat of predators
is quite large (Perhutani 1993).
At the beginning of the implementation of the silvofishery pond system, aquaculture
production will decline because it has not received ecological benefits from the mangrove
ecosystem, but when the ecosystem function has returned silvofishery ponds will get a greater
profit than the mangrove ecosystem non-silvofishery ponds. This also occurs in the case of
organic farming activities which are also sustainable utilization efforts in agriculture. At the
beginning of the application of agriculture, agricultural production will decrease due to the
need for a conversion period to degrade the remaining chemicals in the soil when used for
conventional agriculture (Mayrowani 2012). The problem in developing this utilization is that
at the beginning of the application of organic farming is considered ineffective, but when the
ecosystem function has returned, some research results say that organic farming if done
properly will provide greater benefits than conventional agriculture, this is due to the higher
price of organic products compared to conventional product prices, lower production material
costs compared to conventional production costs, and better and healthier product quality
(Sugino 2010). Thus, silvofishery can be one of the right alternatives in an effort to utilize
mangrove ecosystems in a sustainable manner.
CONCLUSION :
In Canang Kering Village, there are two pond systems, namely silvofishery ponds and
non-silvofishery ponds. The advantage of silvofishery ponds is that they have three harvest
seasons a year, while non-silvofishery ponds only have two harvest seasons a year. Input use
per growing season in silvofishery pond systems is lower than in non-silvofishery ponds.
The results of income analysis showed that the income of silvofishery farmers is greater than
non-silvofishery farmers. Based on the value of the R / C ratio obtained, both farming
systems have a value of more than one, so that both farming systems are profitable. Based on
the comparison of income, farmers who apply silvofishery system has a higher level of
income and R / C ratio because it produces higher output despite lower inputs.
The results of the analysis of financial and economic feasibility with NPV, BCR, IRR, and PP
indicators show that this silvofishery pond business is feasible to run. This can be seen from
the analysis of financial and economic feasibility criteria that meet the requirements.
Factors influencing farmer decisions to implement silvofishery farming are formal education,
farm size, and participation in training.
