Environmental Sciences, Vol. 4, 2016, no. 1, 23 - 29
HIKARI Ltd, www.m-hikari.com
http://dx.doi.org/10.12988/es.2016.51012


Cultivation of Caulerpa lentillifera Using Tray and

Sowing Methods in Brackishwater Pond


Maria Danesa S. Rabia

Bohol Island State University
Calape, Bohol, Philippines

Copyright © 2015 Maria Danesa S. Rabia. This article is distributed under the Creative
Commons Attribution License, which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.

Abstract

Commercial cultivation of Caulerpa lentillifera is now gaining recognition
because of the increasing demand in the domestic and international market.
Studies on the different culture methods for large scale production of the species
in the country are scarce. The present study evaluated the effects of two
cultivation methods namely sowing and tray on the growth and biomass
production of C. lentillifera cultured in brackishwater pond. For the tray method,
propagules were clipped in two 0.75 m x 0.75 m tray and were hung in bamboo
frame whereas for the sowing method, propagules were planted directly in the
pond substrate with an interval of one meter. The weight gain using the sowing
method was significantly higher and could be translated to an average of 1 kg
every month of new or harvestable biomass. Specific growth rate of C. lentillifera
grown in the substrate was at 3.85% day-1 during the first month and at 2.92%
day-1 during the second month and was significantly higher compared to that of
stocks grown in trays. High organic load of the soil (substrate) could have
improved growth and biomass productivity. The results show that cultivation of
C. lentillifera using the sowing method is more effective. This system has
significantly contributed to increase in biomass yield. Moreover, this method of
farming entails lesser capital outlay without any other material requirements such
as bamboos and trays.


Keywords: Caulerpa lentillifera; Cultivation




24 Maria Danesa S. Rabia


Introduction

Green seaweeds from the genus Caulerpa particularly Caulerpa lentillifera and
Caulerpa racemosa are consumed all throughout the Philippines. Both species are
called sea grapes because of the grape-like tiny spherical beads tightly packed
together on the stems. C. lentillifera or locally known as “lato” is more preferred
because of its light, refreshing taste, soft and succulent texture (FAO, 1999). It is a
popular seafood delicacy eaten as raw dip only in vinegar or used in fresh salads
with other seafood and vegetables. It has gained recognition in the international
seafood industry because of its high nutritional value. According to Saito et al.
(2010), it has relatively high polyunsaturated fatty acids including omega 3 fatty
acids. It has also high mineral content such as zinc and iron and trace elements
including cobalt, selenium and valium that meet daily body requirements (Peña-
Rodriguez et al., 2011).

This seaweed is adaptable to a variety of environments making it suitable for
cultivation in ponds. It naturally inhabit a wide range of substrate consisting of
rubbles to over 50 meters deep, sand on reef flats and shallow, muddy lagoons and
forms beds and meadows in excellent condition habitats. However, it is sensitive
to changes in salinity being stenohaline; salinities lower than 30 ppt result to poor
growth and lower than 25 ppt salinity cause mortality.

Trono (1988) accounted the cultivation of C. lentillifera in the country and studied
the culture method. It started in early 1950s when it was accidentally introduced
in fishponds with some other seaweed as feed in the province of Cebu. The
culture technology of this species is relatively simple. Existing milkfish ponds can
be used for cultivation. Cuttings are used as planting material and are planted one
meter apart in the pond bottom. After the cuttings have rooted and started to grow,
regular water exchange is needed to maintain a fresh supply of nutrients and
maintain good water quality. Fertilization is done during the later stage when the
seaweed is almost harvestable and the natural nutrients may no longer available to
support the biomass. Fertilizer is applied using the “teabag” method wherein sacks
of fertilizers are suspended in the ponds. Paul & de Nys, 2011 evaluated the use a
culture vessel or tray in the cultivation of C. lentillifera. The vessels are square
perforated plastic trays with an area of almost 1 m2. Culture trays were rotated
every 4 days, moving randomly positions with the system. They found out that
this method is highly feasible.

The increasing demand for domestic consumption and international trade has led
to the commercial cultivation of the species. Among the other varieties of
Caulerpa, commercial aquaculture production only exists for C. lentillifera (Paul
& de Nys, 2008). Nonetheless, different culture methods for large scale
production of the species in the country are rarely evaluated. The development of
a practical commercial production system will significantly contribute to increase
in biomass yield and control of production cycles.

Cultivation of Caulerpa lentillifera 25


Objective

The main objective of the study was to determine the effects of different
cultivation methods (sowing and tray) on the growth and biomass production of
C. lentillifera cultured in brackishwater pond. The results of the study could serve
as basis in the development of effective culture system of C. lentillifera in
brackishwater pond.


Materials and Methods

Experimental Design

The experiment utilized a complete randomized design with two treatments
corresponding to the cultivation methods: tray and sowing. Growing of C.
lentillifera lasted for 60 days. The experiment was conducted in a private
brackishwater fishpond located at Bentig, Calape, Bohol.

Pond and Set-Up Preparation

Two ponds with an area of 37.5 m2 each were used in the experiment; each pond
was assigned respectively to the two culture methods tested. Standard methods of
pond preparation were observed. The ponds were dried and weeds were removed.
Weeding is very important to get rid of other algae that might compete with C.
lentillifera. Tea seed was added at 100 ppm to eradicate naturally occurring
predators in the mud and lime at 100 ppm was applied subsequently. Ponds were
fertilized with urea and cow manure at a rate of 100 ppm and 1500 ppm
respectively. The incoming water was screened to prevent the entry of other
organisms. The depth of the water was maintained at 1.2 – 1.5 m depth all
throughout the experiment.


Stocking and Water Quality Monitoring

C. lentillifera shoots or fronds were collected from a private Caulerpa farm. The
propagules were weighed and stocked according to the method of cultivation
used. For the tray method, 2,500 grams of propagules was used for each tray. The
propagules were clipped in two 0.75 m x 0.75 m tray; a total of 18 trays were
utilized. For the sowing method, 250 grams of propagules was planted directly in
the pond substrate with an interval of one meter; a total of 18 points were sowed.
Water quality parameters such as salinity, temperature and pH were monitored
daily. Water exchange (25% of pond water) was done daily to maintain necessary
level of nutrients required for growth.



26 Maria Danesa S. Rabia


Biomass Production Monitoring

Growth and biomass were monitored monthly by sampling three trays and sowed
points randomly. Total production yields were evaluated after 60 days. Pond
water was drained prior to final harvesting. Biomass was determined by weighing
the total harvested C. lentillifera for each treatment. Frond density was calculated
by counting the number of fronds protruding above the tray and number of fronds
that grow in the sowed propagules. Frond length was determined by measuring
the length of newly grown fronds using a caliper. To estimate the specific growth
rate (SGR), the following formula was used: SGR = [(ln final weight − ln initial
weight)/days] x 100. Where: ln = natural logarithm of final and initial weight.

Statistical Analysis

All data were subjected to T-test. Differences were considered significant at the p
< 0.05 level.

Results and Discussion

Water Quality

Important water quality parameters such as pH, salinity and temperature were
monitored twice a day, early in the morning and late in the afternoon to check
fluctuations that could affect the results of the study. Within the duration of the
experiment, the water quality parameters recorded were within the favorable range
for seaweed culture as manifested from their morphological features and relatively
high growth rates; the pH was at 7.9-8.4, salinity was at 29-37 ppt and
temperature at 28-31oC.

Growth

Total biomass productivities for C. lentillifera of the two methods are presented in
Figure 1. After 30 days of culture, C. lentillifera in the tray method gained 800 g
which is equivalent to 32% based on the initial weight while in the sowing method
1,190 g was added to total biomass which is equivalent to 476% increase based on
the initial weight. After 60 days, C. lentillifera in the tray method gained another
649 g and accrued a total of 58% weight increment while in the sowing method
swelled to almost double gaining another 1030 g and accumulated a total of 888%
weight increment based on the initial weight. The weight gain using the sowing
method was significantly higher and could be translated to an average of 1 kg
every month of new or harvestable biomass. High organic load of the soil
(substrate) could have improved biomass productivity. The weight gain obtained
in the present study however is relatively lower compared to the report of Paul et
al. (2009). They found out that total biomass productivity of C. lentillifera
monoculture in plastic trays was at 1.5 kg week-1. The culture system used a tip

Cultivation of Caulerpa lentillifera 27


bucket to generate sporadic and turbulent water renewals and this was a key
feature to sustaining biomass productivity with high biomass densities.

Average monthly growth rate is presented in Figure 4. Generally, there was a
decline in the growth rate after 30 days of culture. Specific growth rate of C.
lentillifera grown in the substrate was at 3.85% day-1 during the first month and at
2.92% day-1 during the second month and was significantly higher compared to
that grown in trays. The results were comparable to specific growth rate of
Kapphycus alvarezii cultured using bottom line and raft monocline methods
(Samonte et al., 1993). The growth rates recorded in the experiment were lower
compared to the average monthly growth rate of Kapphycus alvarezii grown on
bamboo raft inside a floating net cage (Hurtado-Ponce, 1992).


Biomass Properties

C. lentillifera is characterized by thallus consisting of long horizontal stolons with
few rhizoidal branches below and many erect, grapelike branches above. The erect
branches are populated with many small capitates ramuli crowdedly attached to
the main axis. There is no significant different in terms of thallus and branch
length of C. lentillifera grown using the two methods (Figure 3).


.



Figure 3. Percentage weight increment of C. lentillifera during the experiment.
Each treatment is a mean of the replicates. Means with different letters indicate
significant differences between treatments (P<0.05)






28 Maria Danesa S. Rabia



Figure 4. Monthly specific growth rate of C. lentillifera. Each treatment is a mean
of the replicates. Means with different letters indicate significant differences
between treatments (P<0.05)


Figure 5. Thallus and branch lengths of C. lentillifera grown using sowing and
tray method after 60 days of culture in brackishwater pond. . Each treatment is a
mean of the replicates. Means with different letters indicate significant differences
between treatments (P<0.05)

Conclusion

C. lentillifera grown using the sowing method had significantly higher growth rate
and biomass production. The results show that cultivation of C. lentillifera using
the sowing method is more effective. This method of C. lentillifera farming
entails lesser capital outlay without any other material requirements such as
bamboos and trays.

Acknowledgments. I would like to express my sincerest gratitude to the
following for the contribution and support in the successful conduct of the study:
Mr. Buenaventura M. Cabangbang for providing us with free C. lentillifera propa-
gules and for allowing us to conduct the experiment in their fishponds; Jomel
Baobao former science research specialist and 4th year BS Fisheries students Arvin

Cultivation of Caulerpa lentillifera 29


Coloso, Christine Alag, Julie Ann Gabi and Gil Vincent Pocot for the assistance
in the conduct of the experiment.


References

[1] M. Avelin, M. Vitalina, L. Araceli, J. Matias, Rediscovery of naturally
occurring seagrape Caulerpa lentillifera from the Gulf of Mannar and its
mariculture, Current Science, 97 (2009), no. 10, 1418-1420.

[2] A.Q. Hurtado-Ponce, Cage culture of Kapphycus alvarezii var tambalang
(Cigartinales, Rhodophyceae), Journal of Applied Phycology, 4 (1992), 311-313.
http://dx.doi.org/10.1007/bf02185787

[3] N.A. Paul, R. de Nys., Invention title: Cultivating Seaweed, Specification for a
patent in the name of James Cook University A01G 33/00 (2006.01). OPI date 07-
04-2011.

[4] N.A. Paul, A.D. Symon, R. de Nys., 2009, Green Caviar and Sea Grapes:
Targeted Cultivation of High Value Seaweeds from the Genus Caulerpa, School
of Marine and Tropical Biology, James Cook University, Townsville 4811.

[5] A. Peña‐ Rodríguez, T.P. Mawhinney, D. Denis Ricque‐ Marie, L.E.
Cruz‐ Suárez, Chemical composition of cultivated seaweed Ulva clathrata (Roth)
C. Agardh, Food Chemistry, 129 (2011), 491–498.
http://dx.doi.org/10.1016/j.foodchem.2011.04.104

[6] H. Saito , C.H. Xue, R. Yamashiro, S. Moromizato, Y. Itabashi, High
polyunsaturated fatty acid levels in two subtropical macroalgae, Cladosiphon
okamuranus and Caulerpa lentillifera, Journal of Phycology, 46 (2010), 665–673.
http://dx.doi.org/10.1111/j.1529-8817.2010.00848.x

[7] G.P.B. Samonte, A.Q. Hurtado-Ponce, R.D. Caturao, Economic analysis of
bottom line and raft monocline culture of Kapphycus alvarezii var tambalang in
Western Visayas, Philippines, Aquacuture, 110 (1993), 1-11.
http://dx.doi.org/10.1016/0044-8486(93)90429-3

[8] G.C. Trono, Manual on Seaweed Culture: Pond Culture of Caulerpa and
Pond Culture of Gracilaria, Marine Science Institute, College of Sciences,
University of the Philippines Diliman. Quezon City, 1988.


Received: October 28, 2015; Published: November 23, 2015