GROWTH AND YIELD OF RED SEAWEEDS (Kappaphycus alvarezii) CULTIVATED
USING BAMBOO RAFT METHOD AT VARIED DEPTHS
IN ALABAT ISLAND, QUEZON
John Paul S. Alpay
Aaron J. Condino
Carlo T. Marinay
Bachelor of Science in Fisheries and Aquatic Sciences
Southern Luzon State University
Alabat Campus
1
Chapter I
INTRODUCTION
The world's oceans and coastal ecosystems play a vital role in sustaining life on Earth,
providing not only a rich diversity of marine species but also essential resources that support human
livelihoods and global food security. Among these invaluable resources, seaweeds, or marine
macroalgae, have gained increasing recognition for their versatility in various applications, from
culinary delights to pharmaceuticals, and their significant role in mitigating climate change by
sequestering carbon dioxide. However, the sustainable cultivation and propagation of seaweeds
present considerable challenges as we navigate an era of increasing environmental pressures and
growing global demand.
Seaweeds, commonly referred to as marine macroalgae, have been recognized as a valuable
resource with immense ecological, economic, and nutritional significance worldwide. Among the
diverse species of seaweeds, Kappaphycus alvarezii, a red seaweed species, holds particular
importance due to its extensive application in various industries such as food, pharmaceuticals,
cosmetics, and biotechnology. The global demand for K. alvarezii continues to surge, primarily
driven by its rich content of carrageenan, a vital hydrocolloid used in the food and beverage
industry. Consequently, the sustainable cultivation of K. alvarezii has garnered substantial attention.
Seaweed cultivation has emerged as a sustainable and environmentally friendly solution to
address various global challenges, including food security, carbon sequestration, and wastewater
treatment (FAO, 2020; Gachon et al., 2010). The cultivation of seaweed offers numerous ecological
benefits, such as nutrient uptake, oxygen production, and habitat provision, while also providing
valuable products for various industries (e.g., food, pharmaceuticals, and biofuels) (Holdt & Kraan,
2011; Msuya et al., 2002). Given its multifaceted role in marine ecosystems and potential
2
contributions to human welfare, there is growing interest in optimizing seaweed propagation
methods to enhance growth and sustainability.
Seaweed cultivation traditionally takes place in open-water environments, such as coastal
areas and shallow bays (Msuya et al., 2002). However, the adoption of more controlled methods,
such as cage-based cultivation, has gained attention due to its potential to overcome challenges
associated with open-water cultivation (Buschmann et al., 2017). The use of cages can protect
seaweed from predation, mitigate the impact of environmental stressors, and allow for the
manipulation of key growth parameters (e.g., light, nutrient availability, and water flow) (Neori et
al., 2004; Pereira et al., 2018). As such, the cage method holds promise for enhancing seaweed
production and ensuring the sustainability of this valuable resource.
The Philippines, blessed with vast coastal areas and favorable marine conditions, has the
potential to become a major player in the production of K. alvarezii. Among its numerous coastal
regions, Alabat Island in Quezon province stands out as an area of great promise for the cultivation
of this valuable red seaweed. However, the traditional seaweed farming methods often face
challenges such as fluctuating environmental conditions, predation, and fouling. These challenges
have led to inconsistent yields and economic uncertainties for local seaweed farmers.
Alabat Island, situated in the Philippines, boasts a rich coastal environment suitable for
seaweed cultivation. This region has witnessed a growing interest in the cultivation of seaweeds,
driven by both local subsistence and commercial production. Various cultivation methods, such as
raft, cage, and longline approaches, have been employed to harness the potential of seaweeds in
Alabat Island. However, assessment of these methods is essential to optimize cultivation practices,
improve yields, and ensure the sustainability of seaweed farming in the region.
Alabat Island, situated in Quezon province, Philippines, offers an ideal setting for red
seaweed cultivation, owing to its favorable climate, abundant coastal resources, and proximity to
3
major markets. However, limited research has explored the cultivation of K. alvarezii in this region,
especially with regard to the influence of water depth on growth and yield.
This research proposal aims to address this knowledge gap by conducting a comprehensive
study on the growth and yield of K. alvarezii cultivated using raft methods at varying depths in
Alabat Island, Quezon. The study will investigate the physiological responses of K. alvarezii to
different depth conditions, assessing growth parameters, such as morphological characteristics.
Furthermore, the economic viability of cultivating K. alvarezii at different depths will be evaluated
to determine the potential for sustainable and profitable seaweed farming in this locality.
The findings of this research will not only enhance our understanding of the ecological
requirements of K. alvarezii but also provide valuable insights for local communities and
aquaculture practitioners seeking to engage in sustainable seaweed farming. Additionally, this
research will contribute to the broader goal of promoting marine biodiversity conservation and the
development of environmentally friendly aquaculture practices.
The findings of this study hold the potential to revolutionize the seaweed farming industry
in Alabat Island and serve as a model for sustainable marine agriculture in similar coastal regions.
Moreover, this research aligns with the broader global goals of promoting sustainable food
production, conserving marine ecosystems, and supporting economic development in coastal
communities. Ultimately, the successful implementation of raft-based seaweed farming methods
can pave the way for a more secure and prosperous future for both the local communities of Alabat
Island and the broader Philippines seaweed industry.
4
Statement of the Problem
The primary aim of this study is to investigating the growth and yield of Red Seaweeds
(Kappaphycus alvarezii) cultivated in bamboo raft methods at varied depths in Alabat Island,
Quezon. Specifically, this research aims to address the following objectives:
1. Determine the growth and yield of Red Seaweeds (Kappaphycus alvarezii) cultivated
in bamboo raft methods at varied depths in Alabat Island, Quezon in terms of:
1.1. Daily growth rate;
1.2. Average growth rate;
1.3. Thallus length and
1.4. Harvest yield (wet and dry weight)
2. Determine the influence of environmental conditions on the Red Seaweeds
(Kappaphycus alvarezii) cultivated in bamboo raft methods at varied depths in Alabat
Island, Quezon in terms of:
2.1. Salinity;
2.2. Turbidity;
2.3. Water temperature;
2.4. pH conditions.
3. Assess the economic feasibility of Red Seaweeds (Kappaphycus alvarezii) cultivated
in bamboo raft methods at varied depths in Alabat Island, Quezon in terms of :
3.1. initial investment,
3.2. operational costs, and
3.3. revenue generated from seaweed production.
4. Provide recommendations for the adoption of the cage culture of seaweed cultivation
metho in Alabat Island based on the findings of the study, with considerations for
environmental conservation and the livelihoods of local communities.
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Significance on the Study
The research will investigate the cultivation of Kappaphycus alvarezii using raft methods
in varwhich holds significant value for multiple stakeholders. It not only contributes to scientific
knowledge but also has the potential to positively impact the local economy, environment, and the
lives of the fisherfolk community. Additionally, it serves as a stepping stone for future research and
development in the field of sustainable aquaculture.
Faculty / Academe: This study contributes to the academic knowledge base by providing empirical
data and insights into the cultivation of red seaweeds using raft methods. It can serve as a valuable
resource for educators and researchers in the field of marine biology, aquaculture, and fisheries
management, helping them stay updated with the latest research findings.
Fisheries Students: This research offers a practical learning opportunity for fisheries students to
gain hands-on experience in seaweed cultivation and marine resource management. It can be used
as a case study for students to understand the complexities and challenges of sustainable
aquaculture practices.
Local Government Unit: The findings of this study can inform local government units (LGUs) in
Alabat Island, Quezon, about the feasibility and potential benefits of seaweed cultivation using
cage methods. This information can be used to develop policies and strategies for promoting
sustainable aquaculture, which can contribute to economic development and food security in the
region.
Fisherfolk Community: The study has direct implications for the fisherfolk community in Alabat
Island. It can serve as a resource to introduce alternative and sustainable livelihood options, such
as seaweed farming, which may reduce the pressure on traditional fishing resources while
improving the income and living standards of fisherfolk.
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Future Researchers: As a foundation for further research, this study can inspire and guide future
researchers to explore related topics or expand on the findings. It can provide a benchmark for
comparison and help identify gaps in knowledge that require further investigation.
Aquaculturists: Aquaculturists can benefit from the practical insights and recommendations
derived from this study. It can help them optimize their seaweed cultivation practices, improve
yields, and contribute to the growth of the seaweed farming industry in the region and beyond.
Scope and Limitation
This study will focus on evaluating the growth and yield of Red Seaweeds (Kappaphycus
alvarezii) cultivated in raft methods at varied depths in Alabat Island, Quezon. The study will
specifically assess the growth and yield of the mentioned seaweed cultivars, as they are of particular
interest in the region. The research will primarily employ raft cultivation techniques to grow the
seaweed cultivars and will include monitoring and data collection over six months culture period.
The study will consider environmental factors such as water temperature, salinity, pH, turbidity,
which can affect the growth and yield of seaweed cultivars. The assessment of growth and yield
will include measurements of biomass production, wet and dry weight, and other relevant
parameters to determine the productivity of K. alvarezii. To some extent, the study may also touch
upon the economic feasibility of cultivating this seaweed cultivar in the Alabat Island marine
environment.
The study may be limited by seasonal variations in environmental conditions, which can
impact the growth and yield of seaweed cultivars. It may be necessary to conduct the study over an
extended period to account for these fluctuations. Specific environmental conditions in Alabat
Island’s marine environment, such as local currents or water quality, may affect the results. These
factors may not be representative of other marine environments. While the study focuses on three
specific seaweed cultivars, the results may not be generalized to all Eucheumatoids seaweed species
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or other types of seaweeds. The economic aspects of seaweed cultivation, such as production costs
and market demand, will be considered to some extent but will not be the primary focus of this
study. The study may face limitations related to the availability of resources, including funding,
equipment, and personnel, which can influence the scale and scope of the research. The study
assumes that the cultivation of seaweed will follow established practices, but human intervention
and management can vary, potentially impacting the results. While the findings will provide
valuable insights into seaweed cultivation in the Alabat Island marine environment, they may not
be directly transferable to other regions with different environmental conditions. The study’s results
are contingent on the availability and accuracy of data collected during the research process. Data
limitations may affect the comprehensiveness of the analysis.
Definition of Terms
The following keywords were defined operationally and contextually for each of the
research objectives:
Daily growth rate: Contextually, this refers to the rate at which the seaweed species grow
on a daily basis when grown in cages in Alabat Island, Quezon. Operationally, it involves measuring
the increase in seaweed size (e.g., length or weight) over each day of cultivation.
Average growth rate: Contextually, this refers to the overall rate of growth of the seaweed
species during the entire cultivation period. Operationally, it involves calculating the average
increase in seaweed size over the entire cultivation period.
Thallus length: Contextually, this refers to the size or length of the seaweed thallus (body)
at the end of the cultivation period. Operationally, it involves measuring the length of the seaweed
thallus using appropriate tools or methods.
Harvest yield (wet and dry weight): Contextually, this refers to the amount of seaweed
harvested at the end of the cultivation period, both in its wet and dry forms. Operationally, it
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involves weighing the harvested seaweed in its wet state and then drying it to measure the dry
weight.
Salinity: Contextually, this refers to the saltiness of the water in which the seaweed is
cultivated. Operationally, it involves measuring the salinity levels of the marine environment in
Alabat Island.
Turbidity: Contextually, this refers to the cloudiness or haziness of the water due to the
presence of particles. Operationally, it involves measuring the degree of turbidity in the marine
environment.
Water temperature: Contextually, this refers to the temperature of the seawater in which the
seaweed is cultivated. Operationally, it involves monitoring and recording the water temperature
regularly.
pH conditions: Contextually, this refers to the acidity or alkalinity of the water.
Operationally, it involves measuring the pH levels of the marine environment.
Initial investment: Contextually, this refers to the amount of money or resources required
to set up the seaweed cultivation using cage methods. Operationally, it involves calculating the
upfront costs of establishing the seaweed cages.
Operational costs: Contextually, this refers to the ongoing expenses incurred in maintaining
and running the seaweed cultivation operation. Operationally, it involves tracking and calculating
the costs associated with day-to-day operations.
Revenue generated from seaweed production: Contextually, this refers to the income
generated from selling the harvested seaweed. Operationally, it involves calculating the total
revenue generated from seaweed sales.
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Chapter II
REVIEW OF RELATED LITERATURES
This chapter serves as the foundational bedrock upon which our own study is built. It
provides a contextual framework for our research objectives, shedding light on the key variables,
theories, and findings that will guide our investigation into the efficiency and sustainability of
seaweed cultivation methods, specifically raft, cage, and longline approaches, in the unique and
ecologically significant setting of Alabat Island. Through this literature review, the proposed study
will aim to not only bridge the gap between existing knowledge and our research objectives but
also to identify areas of convergence, divergence, and the potential for novel contributions to the
field of seaweed cultivation, both locally and globally.
Review of Related Literatures
Seaweed cultivation is a significant component of aquaculture and has gained prominence
as an alternative source of income and food security for coastal communities (Neish et al., 2015).
This review explores the existing literature on seaweed cultivation methods, with a focus on the
raft, cage, and longline approaches, in the context of Alabat Island.
Municipal Fishing Profile of Alabat Municipality
The waters surrounding the Alabat Municipality are known for their diverse marine life.
They provide habitat to a wide range of fish species, including both commercially valuable and
subsistence species. This diversity makes the area attractive for fisheries. The Alabat Municipality
is known for its commercial fisheries, with local fishermen and fishing communities actively
engaged in activities such as trawling, purse seining, and longlining. Key target species include
various types of tuna, mackerel, sardines, and other pelagic and demersal fish. Aquaculture is
another important component of the fisheries profile in the Alabat. Fish farming operations,
including the cultivation of milkfish (bangus), tilapia, and shrimp, contribute significantly to the
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local economy. Ponds, cages, and pens are commonly used for aquaculture. Many residents of the
Alabat rely on traditional and subsistence fishing practices to meet their daily needs. This includes
small-scale fishing using methods such as hook and line, traps, and hand nets. The catch from these
activities often includes reef fish, crustaceans, and mollusks (LGU Alabat, undated).
Overfishing is a concern in the region, as increased fishing pressure can lead to the
depletion of fish stocks and disrupt local ecosystems. Sustainable fishing practices and regulations
are essential to address this issue. Destructive fishing practices, such as dynamite and cyanide
fishing, can cause damage to coral reefs and marine habitats. Conservation efforts are underway to
protect these critical ecosystems. The effects of climate change, including rising sea temperatures
and ocean acidification, can impact the distribution and abundance of fish species in the area.
Adapting to these changes is a challenge for the local fishing communities (GMA, 2015). Effective
fisheries management, including the establishment of marine protected areas (MPAs) and the
enforcement of fishing regulations, is crucial to ensure the sustainability of fisheries resources in
the Alabat Islands (BFAR, 2021)
The fisheries sector In the Alabat Islands plays a significant role in the local economy,
providing livelihoods for many residents. It contributes to food security, income generation, and
employment opportunities in the region. However, balancing economic interests with conservation
efforts is a continuous challenge. Municipality of Alabat have a diverse and important fisheries
profile, with both commercial and subsistence fishing activities. Sustainable management and
conservation efforts are essential to ensure the long-term health of marine resources in this region,
while also supporting the livelihoods of local communities. To obtain the most recent and detailed
information on the fisheries profile of the Alabat Islands, it is advisable to consult local authorities,
government agencies, or research institutions.
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Seaweed Cultivation
Seaweed cultivation in the Philippines primarily involves Eucheuma and Kappaphycus
species due to their high commercial value. According to Hernandez et al. (2018), various
cultivation techniques, such as the floating raft and line methods, have been adopted to
accommodate the different species and environmental conditions in the Philippines.
Studies like Nishijima et al. (2016) have examined the environmental impact of seaweed
farming, emphasizing its potential to mitigate ocean acidification and improve water quality
through nutrient uptake. However, over-exploitation and improper farming practices can also lead
to adverse environmental effects, including habitat degradation.
Seaweed farming plays a crucial role in income generation for coastal communities. Chua
and Nacorda (2019) found that seaweed farming provides a stable source of income for small-scale
farmers, contributing to poverty alleviation and economic resilience. A study by Roleda et al.
(2017) highlights the growing global demand for seaweed-derived products, such as carrageenan
and agar. The Philippines has become a leading exporter of these products, creating economic
opportunities for the country. Community-based management of seaweed farms is a common
practice in the Philippines. A research by Geronimo et al. (2019) underscores the importance of
community involvement in governance and decision-making, which fosters sustainability and
social cohesion. Gender dynamics in seaweed farming have been explored by Santos et al. (2018).
Their study reveals that women often play key roles in seaweed farming, challenging traditional
gender roles and empowering women in coastal communities.
Seaweed farming in the Philippines faces challenges related to climate change, disease
outbreaks, and market fluctuations. Researchers like Salinas and Hurtado (2019) emphasize the
need for sustainable farming practices, disease management, and diversification of seaweed
products to address these challenges.
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Environmental and Economic Considerations
Seaweed cultivation methods have distinct environmental and economic implications. Raft
and cage systems may provide opportunities for community-based cultivation and livelihood
improvement (Turon & Collado-Vides, 2017). However, they may also be susceptible to
environmental stressors and disease outbreaks (Cruz-Lacierda et al., 2019). Longline systems, on
the other hand, are less labor-intensive but require careful consideration of their environmental
impact (Angell & Angell, 2017).
Ecological Aspects of Seaweed Cultivation
The Philippines’ extensive coastline and suitable environmental conditions have made it a
hub for seaweed farming (Ohno & Iehisa, 2019). Research by Gomez et al. (2017) highlights the
diverse seaweed species found in the country, including Eucheuma spp., Kappaphycus spp., and
Gracilaria spp., which are commonly cultivated for their economic value. Environmental factors
such as water temperature, light availability, nutrient levels, and water quality play a critical role in
seaweed growth (Pangilinan et al., 2018). These factors vary across the archipelago, necessitating
site-specific cultivation practices and strategies (Gomez et al., 2017).
Socioeconomic Implications
Seaweed cultivation contributes significantly to the livelihoods of coastal communities in
the Philippines (Neish et al., 2015). Research by Cruz et al. (2018) emphasizes the role of seaweed
farming in income generation, poverty alleviation, and gender empowerment. Community-based
seaweed farming initiatives have been successful in enhancing the economic well-being of local
populations (Neish et al., 2015). However, challenges such as market fluctuations, disease
outbreaks, and limited access to capital and technology can affect the sustainability of seaweed
cultivation enterprises (Turon & Collado-Vides, 2017). Effective governance and support
mechanisms are essential to mitigate these challenges (Cruz-Lacierda et al., 2019).
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Technological Advancements
Technological advancements have played a pivotal role in enhancing the efficiency and
sustainability of seaweed cultivation in the Philippines (Ohno & Iehisa, 2019). Innovations in
seedstock production, propagation techniques, and farming practices have led to increased yields
and reduced environmental impacts (Pangilinan et al., 2018). Additionally, the introduction of
floating rafts, cage systems, and longline cultivation methods has diversified cultivation approaches
(Cruz-Lacierda et al., 2019).
Sustainability and Environmental Impact
Sustainability concerns in seaweed cultivation include the potential for seaweed farming
to negatively impact coastal ecosystems through nutrient enrichment, habitat alteration, and
competition with native species (Ohno & Iehisa, 2019). Research by Angell and Angell (2017)
emphasizes the importance of integrated coastal management practices to mitigate these ecological
risks.
Seaweed cultivation in the Philippines is a multifaceted industry with significant
ecological, socioeconomic, and technological dimensions. The diverse range of seaweed species,
coupled with varying environmental conditions, highlights the need for site-specific cultivation
practices. Sustainable seaweed farming has the potential to continue contributing to the livelihoods
of coastal communities, but challenges such as market fluctuations and environmental impacts must
be addressed through effective governance and technological innovations.
Seaweed farming in the Philippines is a significant economic activity that provides
livelihoods for coastal communities and contributes to the country’s export industry. Among the
various methods employed in seaweed cultivation, the raft method has gained popularity due to its
cost-effectiveness, scalability, and relatively low environmental impact.
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The Philippines is one of the world’s leading producers of seaweed, with carrageenanproducing seaweed species, such as Kappaphycus alvarezii and Eucheuma denticulatum, being the
primary focus of cultivation (Hurtado et al., 2008). Seaweed farming in the country predominantly
takes place in coastal areas, with a significant presence in regions like Mindanao, Visayas, and
Palawan (Gonzales & Montaño, 2008). Seaweed farming in the Philippines, particularly using the
raft method, plays a vital role in the country’s coastal communities and economy. The cultivation
of carrageenan-producing seaweeds on rafts has demonstrated economic viability, environmental
sustainability, and potential for further growth. However, addressing the existing challenges and
implementing sustainable practices will be crucial for the long-term success of this industry in the
Philippines.
Raft-Based Seaweed Cultivation
The raft method involves the cultivation of seaweed on floating structures, typically
bamboo or PVC rafts, which are anchored in shallow coastal waters. This method offers several
advantages, including ease of management, reduced vulnerability to strong currents and storms,
and the ability to rotate crops for improved seaweed quality (Perez, 2012). Raft-based cultivation
involves the suspension of seaweed within a buoyant platform (Turon & Collado-Vides, 2017).
Studies suggest that raft-based systems are popular due to their scalability and ability to grow
multiple seaweed species simultaneously (Neish et al., 2015). Alabat Island’s geographical location
and suitable conditions make it an ideal location for such systems (Cruz-Lacierda et al., 2019).
Raft-based seaweed farming involves the cultivation of seaweed species on floating rafts
or platforms anchored in the sea. According to Campbell et al. (2016), this method offers several
advantages, including ease of scalability, reduced risk of disease, and enhanced water quality
control. It has become a popular choice for seaweed farmers seeking to optimize yields and
minimize environmental impacts. Seaweed farming on rafts has been associated with positive
environmental effects, such as nutrient uptake and carbon sequestration (Neori et al., 2004). These
15
ecosystem services make raft-based seaweed farming an attractive option for mitigating the effects
of eutrophication and climate change. Despite its advantages, raft-based seaweed farming faces
challenges related to fouling, biosecurity, and market demand. Research by Msuya et al. (2019)
discusses these challenges and suggests strategies for sustainable growth in the seaweed farming
industry.
Seaweed farming has been instrumental in providing employment opportunities and
income generation for coastal communities in the Philippines (Neish & Potter, 2010). The raft
method’s cost-effectiveness and relatively low capital requirements make it accessible to smallscale farmers. Compared to other forms of aquaculture, seaweed farming is considered
environmentally friendly as it requires no additional feed, reduces nutrient pollution, and provides
habitat for marine organisms (Hayashi et al., 2014). The Philippines is a leading global producer of
carrageenan, which is extracted from seaweeds cultivated using the raft method. Carrageenan has
various industrial applications, including food and pharmaceuticals (Hurtado et al., 2008). Despite
its many benefits, seaweed farming using the raft method faces challenges such as disease
outbreaks, market fluctuations, and competition for coastal resources (Largo et al., 2019). Future
research should focus on enhancing disease management, improving farming practices, and
exploring market diversification to sustain and further develop this industry.
The raft method of seaweed farming holds great promise for the sustainable production of
seaweed and its associated benefits. However, it is essential for researchers and practitioners to
address challenges related to fouling, biosecurity, and market development to unlock the full
potential of this cultivation technique. Further research and innovation are needed to advance the
practice of seaweed farming on rafts. Factors such as environmental conditions, economic
feasibility, and community engagement need to be carefully considered in making this choice.
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Conceptual Framework
This conceptual framework will guide the researchers systematically investigate the growth, yield,
and feasibility of Red Seaweed cultivation in bamboo rafts in Alabat Island, Quezon using InputProcess-Output Approach. Overall, this conceptual framework provides a structured approach to
address the objectives of the research study and presents a clear path from input factors to the
desired outputs and recommendations.
Input: This component includes the environmental factors and the specific cultivation method used
in the study. Environmental factors such as salinity, turbidity, water temperature, and pH conditions
may influence the growth and yield of Red Seaweeds. The bamboo raft system and varying depths
are the chosen methods for cultivation.
Process: This component outlines the key aspects being studied. It involves the growth and yield
of Red Seaweeds, including daily and average growth rates, thallus length, and harvest yield.
Additionally, an economic feasibility assessment is conducted, focusing on initial investment,
operational costs, and revenue generated from seaweed production.
Output: The output component represents the outcomes of the study. This includes data on the
growth and yield of Red Seaweeds under different conditions, as well as an economic viability
analysis. The recommendations section provides guidance based on the findings, including
suggestions for the adoption of the cage culture of seaweed cultivation method, environmental
conservation considerations, and strategies to support the livelihoods of local communities.
The conceptual framework for the research study focused on investigating the growth and yield of
Red Seaweeds (Kappaphycus alvarezii) cultivated in bamboo raft methods at varied depths in
Alabat Island, Quezon, using the Input-Process-Output (IPO) approach. The conceptual framework
outlines the main components of the study and how they are interconnected was illustrated on
Figure 1.
17
Conceptual Paradigm
1. Depth of
cultivation
2. Environmental
conditions
(salinity, turbidity,
water temperature,
pH)
3. Economic factors
(initial investment,
operational costs,
revenue)
Input
1. Seaweed Growth
and Yield:
 Daily growth rate
 Average growth
rate
 Thallus length
 Harvest yield (wet
and dry weight)
2. Economic
Feasibility
Assessment:
 Initial investment
 Operational costs
 Revenue generated
from seaweed
production
Process
1. Growth and Yield
Data:
 Data on growth
rates, thallus length,
and yield of
Kappaphycus
alvarezii at different
depths and under
varying
environmental
conditions.
2. Economic Viability
Analysis:
 Assessment of the
economic feasibility
of seaweed
cultivation in the
studied area.
3. Recommendations:
 Suggestions for the
adoption of the cage
culture of seaweed
cultivation method
in Alabat Island.
 Considerations for
environmental
conservation.
 Considerations for
the livelihoods of
local communities.
Output
Figure 1. the Conceptual Framework of the Study
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Chapter III
RESEARCH METHODOLOGY
This chapter outline the comprehensive approach to be employed to gather, analyze, and
interpret data, providing a clear roadmap for understanding how these seaweed cultivars thrive
when subjected to cage cultivation method. Through this meticulous methodology, it aim to unearth
valuable insights into sustainable seaweed farming practices, contributing to both the scientific
understanding of these organisms and the potential for economic development in coastal
communities.
Research Locale
The research study will be conducted in Alabat Island, particularly in Brgy. Balungay, Alabat,
Quezon. The Municipality of Alabat is located in the province of Quezon, which is part of the
CALABARZON region in the Philippines. It is situated on Alabat Island, which is surrounded by
the waters of Lamon Bay and the Philippine Sea, making it an important area for fisheries. Alabat's
coastal areas are rich in marine biodiversity, providing a diverse range of fish species, crustaceans,
and mollusks. Common fish species include bangus (milkfish), galunggong (round scad), tilapia,
and various types of reef fish. Commercially valuable species such as tuna and snapper are also
present in the deeper waters off the coast. Aquaculture is a significant component of the local
fisheries industry. Fishponds, particularly for raising bangus (milkfish) and tilapia, are common in
the area. There may also be smaller-scale aquaculture operations for seaweeds, shrimp, crabs, and
prawns.
19
Figure 1. Map of Brgy. Balungay, Alabat, Quezon and the proposed site (encased in yellow box)
Figure 2. Map of Alabat Island and its municipalities.
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Research Design
The study will use experimental research design in the comparative assessment of seaweed
cultivation methods in Alabat Island and offers a roadmap for collecting and analyzing data to
answer the research objectives. Experimental research design is a scientific approach used to
investigate cause-and-effect relationships between variables. It involves manipulating one or more
independent variables (IVs) to observe their effects on one or more dependent variables (DVs)
while controlling for extraneous variables. Experimental research design is a powerful method for
investigating causal relationships between variables by systematically manipulating and controlling
them. Its implications include the ability to establish cause-and-effect relationships, precision in
identifying specific factors, replicability for validation, considerations of generalizability, and
ethical responsibilities toward participants.
The primary aim of this study is to evaluate the growth and yield of Red Seaweeds
(Kappaphycus alvarezii) cultivated in raft methods at varied depths in Alabat Island, Quezon. using
a Randomized Complete Block Design (RCBD) which involves a systematic approach to
investigate and compare the growth and yield of three different seaweed cultivars under controlled
experimental conditions. RCBD is a statistical design that helps reduce the potential for bias and
improve the accuracy of the results by accounting for variability in the environment.
The study will employ three treatments with Red Seaweeds (Kappaphycus alvarezii)
cultivated in raft methods at varied depths of 1.0 meters, 2.0 meters and 5.0 meters, as Treatments
1, 2 and 3, respectively, all will be replicated thrice.
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Experimental Lay-out
The study will employ nine units of bamboo raft for the study. Each of the units will have a distance
of 10 meters interval from each other.
Legend : blue box – Treatment 1; orange box - Treatment 2 and green box - Treatment 3
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Materials and Methods
Site Selection
The study will be conducted at Brgy. Balungay, Alabat, Quezon. This is chosen as previous
seaweed cultivations were constructed in this particular area. The Alabat shore includes sand-fat
tidal regions, with minimal turbulence. This area's water quality attributes based on the study of
Luna (unpublished thesis) are ideal for the growth and periodic availability of various macroalgae
species. The area experiences a sufficient exchange of water due to the continuous flow of the
current in the region. As a result, Alabat is a unique location for seaweed cultivation.
Suitable sites for seaweed cultivation will be selected based on the following criteria: •
Stable seawater with not less than 30 ppt salinity • Sandy/ rocky bottom with transparent water •
Ideal temperature 26-30 oC. • The area should have minimum 1.0 m water depth during low tide. •
Area with mild water currents are preferred. Researchers will be surveying research locations that
were suitable for seaweed cultivation. Determining the location of the study includes the condition
of the bottom of the water, the depth and quality of water including temperature, current speed, pH
and brightness.
Purchase of Seaweed Seedlings
Researchers will get and select good quality seedlings at the nearby fishing locality of
Calauag, Quezon; these are brittle, shiny and young branches with sharp pointed tips, no traces of
grazing or whitened thallus (sign of beginning “ice-ice” disease). Healthy, epiphyte-free, and
untreated seaweeds will be procured from a seaweed farm at Calauag Quezon. The seedlings will
be carefully cut and weighed using a weighing scale to achieve a consistent weight of 100 grams
each. Subsequently, they were securely fastened to a rope line (number 4) using a straw (Softie).
The collection and purchase of seaweed seedlings will approved by the local authorities, and the
biological identity of seaweed species will be confirmed by the reference sample.
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Construction of Raft
The bambop raft will be made of bamboo, rope, and concrete anchors. One unit is
composed of four bamboos arranged in a square shape. Researchers will install 10 m x 10 m
bamboo raft (made of bamboo poles having 7.5 to 10 cm diameter). Rafts will be fixed at the bottom
at the varied depth using 15 kilograms concrete anchors at the farming site. Seaweeds seedlings
(100 g) will be tied to polyethylene rope (PER) #8 tied vertically to the bamboo raft using strawlace
while at the shore. Four (4) PE ropes of 10 meters length will be tied vertically at each unit of
bamboo raft with interval of 2 meters from each other. Forty (40) Clusters of seedling each
weighing 100 grams will be tied individually at each ropes with the distance between seedlings at
25 cm. In total, there will be nine (9) units of rafts for the experiment. Fishing nets will be tied
underneath to protect the seedlings from the grazers.
Figure 3. The design of the raft method that will be used in the study (adapted from SEAFDEC,
2002).
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Preparation of Farm Site
Prior to planting, an ocular inspection of the site will be conducted, lasting one or two days.
Cleaning and clearing activities were then carried out, including the removal of siltation, debris,
sea urchins, starfish, and other organisms that feed on seaweeds. The chosen site is located far from
freshwater sources, ensuring it is free from wave actions and distant from water transport highways.
Importantly, the site benefits from a continuous flow of current, providing sufficient water
circulation.
Culture Days
The culture of red seaweeds will be conducted for specific days based on the recommended
culture days for K. alvarezii by Hurtado-Ponce (2002) as cited by Tahilludin et al.(2022).
Cultivation will be conducted for 60 days in a cycle (total of 1 cycle) representing the wet season.
During the cultivation, measurement of water condition and quality will be carried out regularly.
Seaweed Preparation
Seaweed used must be one clump tied at each rope. Before stocking, seaweed seedlings
needed acclimatization to adapt, by soaking seaweed in a place that will be used for planting.
Acclimatization aims to prevent shock. the planting of seaweeds will took place during low tide.
Sampling and Observation
Observation of seaweed growth and yield will be conducted at the beginning of stocking
and every 15th day throughout culture period. Moreover, water quality observation for parameter
such as temperature, salinity, pH, turbidity will be measured every 15 days. From each line
consisting of 40 plants, five plants will be randomly selected to represent each treatment. These
detached plants were then weighed using a weighing scale and measured in total length using ruler.
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The specific growth rate will be calculated using the following formula derived from Tahiluddin et
al. (2022a).
Collection of Data
The data that will be collected in this study will consist of weight data, water quality and
economic feasibility of seaweed cultivation. Techniques of data collection are described as follows:
1. Weights and biomass were measured weekly by sampling each group of different straps and
columns per treatments and replicates. Seaweed samples will take 1 sample per strap of each
column in every replicates of each treatments; 2. Water quality parameter consisted of depth, ,
temperature, pH, dissolved oxygen, and salinity measured in situ every week; and 3. economic
feasibility of Red Seaweeds (Kappaphycus alvarezii) cultivated in bamboo raft methods at varied
depths in Alabat Island, Quezon in terms of :initial investment, operational costs, and revenue
generated from seaweed production will be analyzed after the conduct of the experimentation.
Permitting
Researchers will obtain the necessary permits and approvals from local regulatory bodies, such as
the Bureau of Fisheries and Aquatic Resources (BFAR) and the local government. Compliance with
environmental regulations and guidelines is crucial.
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Statistical Treatments
In the data analysis, a two-way analysis of variance (ANOVA) will be performed using the SPSS
Version 20 software application. The obtained data will be presented as mean ± standard error (SE),
and the level of significance will be set at 0.05. The homogeneity of variance will be verified and
the Turkey’s test will be used for the multi comparison of means at the level confidence of 5 %.
Pearson correlations will be also investigated to have some information on the relationship between
all the studied parameters.
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