e-ISSN:2528-0759; p-ISSN:2085-5842
JIPK. Volume 11. No 1. April 2019 		
			
DOI=10.20473/jipk.v11i1.10635
		
Available online at https://e-journal.unair.ac.id/JIPK/index

JIPK

JURNAL ILMIAH PERIKANAN DAN KELAUTAN
Research Article

Occurrence of Pedunculate Barnacle, Octolasmis spp. in Blue Swimming Crab, Portunus
pelagicus
Tingkat Kejadian Pedunculate Barnacle, Octolasmis spp. pada Rajungan, Portunus pelagicus
Marina Hassan*1, Mohd Fazrul Hisam Abd Aziz2, Kismiyati3, Sri Subekti4, Mohd Ihwan Zakariah1
Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia.
School of Fisheries and Aquaculture Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia.
3
Department of Fish Health Management and Aquaculture, Faculty of Fisheries and Marine, Universitas Airlangga, Surabaya,
Indonesia.
4
Department of Marine, Faculty of Fisheries and Marine, Universitas Airlangga, Surabaya, Indonesia.
1
2

ARTICLE INFO
Received: December 04, 2018
Accepted: March 19, 2019
*) Corresponding author:
E-mail: marina@umt.edu.my
Keywords:

Octolasmis spp., Portunus pelagicus, identification, site specificity, prevalence, mean intensity
Kata Kunci:

Octolasmis spp., Portunus pelagicus, identifikasi, site specificity, prevalence, mean intensity

Abstract
Barnacles are symbiont and harm to the crabs when they are in large numbers. They will
affect the respiration, normal activity and growth of the crabs. The prevalence, mean intensity and identification of pedunculate barnacle, Octolasmis spp. on blue swimming crab,
Portunus pelagicus from coastal area of Kuala Terengganu were studied. The site specificity of the different species of Octolasmis attached was examined. The crabs were measured
and weight. The crabs were euthanized by put in ice until no movement. The Octolasmis
were observed from the surfaces and gills or brachial chamber. The Octolasmis were observed from each gill. The prevalence and mean intensity were calculated. The Octolasmis
were preserved in 70% alcohol and mounting using glycerine jelly to make permanent
slide. A total of all 13 crabs were infested by four species of Octolasmis which is 218 Octolasmis angulata, 191 Octolasmis warwickii, 16 Octolasmis tridens and 218 Octolasmis
lowei. Octolasmis angulate showed highest prevalence (84.62%) and lowest prevalence
was O. lowei (23.08%) and O. warwickii (23.08%). The barnacles were attached to the
gill, carapace, abdomen and also walking legs. Barnacle occurred most frequently on the
gill part by having 371 (57.70%) barnacles compared to other areas, 272 (42.30%) barnacles. The distributions of barnacle in this study suggest distal areas are more susceptible in
infestation by Octolasmis spp. However, they did not show site specificity on the gill areas
because it depends on the water current.
Abstrak
Barnacle (teritip) adalah simbion yang dalam jumlah besar akan membahayakan kepiting.
Teritip tersebut berpengaruh pada pernapasan, aktivitas normal dan pertumbuhan kepiting. Prevalensi, intensitas rata-rata dan identifikasi pedunculate barnacle, Octolasmis spp.
pada rajungan, Portunus pelagicus dari daerah pesisir Kuala Terengganu telah diteliti.
Kekhasan lokasi dari berbagai spesies Octolasmis telah diperiksa. Kepiting telah diukur
dan ditimbang. Kepiting dieuthanasi dengan cara dimasukkan kedalam es sampai tidak
bergerak. Octolasmis diamati dari permukaan tubuh dan insang (branchial chamber). Octolasmis diamati pada tiap insang. Prevalensi dan intensitas rata-rata dihitung. Octolasmis
diawetkan dalam alcohol 70 % dan mounting menggunakan Jeli gliserin untuk membuat
slide permanen. Semua kepiting 13 ekor telah terinfestasi oleh empat spesies Octolasmis,
yaitu 218 Octolasmis angulata, 191 Octolasmis warwickii, 16 Octolasmis tridens dan 218
Octolasmis lowei. Octolasmis angulate menunjukkan prevalensi paling tinggi (84,62%)
dan prevalensi paling rendah adalah O. lowei (23,08%) dan O. warwickii(23,08%). Teritip
menyerang insang, karapas, abdomen dan juga kaki jalan.Teritip paling sering ditemukan
pada bagian insang 371 ekor (57,70%) dibandingkan pada bagian lain, 272 ekor (42,30%).
Distribusi teritip pada penelitian ini menunjukkan bahwa bagian distal lebih rentan mengalami infestasi Octolasmis spp. Namun, teritip tidak menunjukkan kekhasan lokasi pada
daerah insang bergantung pada arus air.

Cite this as: Marina, H., Fazrul, H., Kismiyati., Sri, S., & Ihwan, M. Z. (2019). Occurrence of Pedunculate Barnacle, Octolasmis spp. in Blue
Swimming Crab, Portunus pelagicus. Jurnal Ilmiah Perikanan dan Kelautan, 11(1):1–8. http://doi.org/10.20473/jipk.v11i1.10635
JIPK (ISSN: 2528-07597), Nationally Accredited Journal of Second Grade (Sinta 2) by Ministry of Research, Technology and Higher Education
of The Republic of Indonesia. Decree No: 10/E/KPT/2018
Copyright ©2019 Universitas Airlangga

April 2019

1

Marina et al., / JIPK, 11(1):1-8

1. Introduction
Crustaceans become a significant species led to
a growing interest in the aquaculture. In Malaysia marine fishery, the total landings of crabs are 3,745 tonnes
in 2010 and increased to 5,579 tonnes in 2013. Johor has
been the major areas for crabs in Malaysia and contributing about 2,929 tonnes of the total production 18,072
tonnes in period 2010 until 2013 (DOF, 2014). Most of
the edible crabs caught in the marine water regions belong to the family Portunidae. Because of the increasing
demands from all over the world, crustacean fisheries
productions are undergoing a significant global expansion. The high nutritive value and good in market price,
many countries in Asia like China (Lai et al., 2010), India (Soundarapandian et al., 2007; Bhat et al., 2011),
Japan (Hamasaki et al., 2011), Thailand (Nitiratsuwan
et al., 2010), Indonesia (Rejeki, 2007) and Malaysia
(Ikhwanuddin et al., 2012) are actively involved in P.
pelagicus fisheries commodity.
Portunus pelagicus commonly live in a wide
range of inshore and continental shelf areas, including
sandy, muddy and seagrass habitat. Unfortunately, the
disease factor became one of the most common problems
that can immobilize the crustacean aquaculture sector.
Thus, it was affect the crustacean production. Themost
study, diseases problem are related to the presence of
pathogenic organisms. But in some cases, the present of
barnacle from Octolasmis spp. usually found on crabs
and cause significant damage to the host. The calcified
carapaces of the crabs appear one of the suitable mobile
habitats for attachment of this barnacle. They will become pathogenic and cause harm to their host when it
present in large numbers on the crabs (Rohde, 1991). As
reported, the barnacles’s attachment in crabs does not
kill the crab but it may affect the crab respiration, normal activity and normal growth of the crabs (Sinduja et
al., 2013). Thus, this study was observed the prevalence
and mean intensity of the Octolasmis spp. found on the
crabs, and identify of the Octolasmis spp. found. The
site specificity of the different species of Octolasmis attached was examined in order to know whether there are
differences of distribution between the species.

2. Materials and Methods
2.1 Portunus pelagicus samples
Portunus pelagicus were collected from Kuala
Terengganu coastal area and brought to Parasitology
Laboratory, Institute of Tropical Aquaculture for examination. A total of thirteen crabs were examined because
of difficulty to catch the crabs during the raining season.

2

Jurnal Ilmiah Perikanan dan Kelautan

The weights of the crabs were measured to the nearest
gram (g) by using a digital electronic balance of 0.1g
sensitivity. The carapace width of crabs were measured
from the tip of the left dorsal spine to the tip of the right
dorsal spine (Bastami et al., 2012). Carapace lengths
of crabs were measured to the nearest centimeter (cm)
from the edge of the frontal region to the tip of the carapace back wall using a vernier caliper (Bastami et al.,
2012). The crabs were pitched by put in ice for a few
minutes or until no movement observed.
2.2 Octolasmis spp site specificity
Dorsal and ventral external surfaces of the carapace and appendages of each crab sample were examined and observed for the barnacles. The site of barnacle
attachment and number of individual barnacle on each
crab found on the external area were recorded. The barnacles were fixed and preserved in 70% alcohol (Ihwan
et al., 2014). The barnacles were mounting using glycerine jelly to make a permanent slide.

Figure 1. Gill division of P. pelagicus (Ihwan et al.,
2014)
The carapace was removed gently by using
forceps for allowing the inspection of barnacle on the
internal area (Kumaravel et al., 2009). The gills were
divided to left and right by followed method by Ihwan
et al., (2014). It was labeled as G1 until G8 (Figure 1).
Each gill was divided into three parts; distal, medial,
and proximal. The gills were observed under a dissecting microscope for the numbers of barnacle attachments. The barnacles were removed by using forceps
and preserved in 70% alcohol and mounting by using
glycerine jelly for permanent slide.
2.3 Identification of Octolasmis spp.
The capitulum length, peduncle of the barnacle
and calcareous plates including branched scutum, carina

JIPK. Volume 11. No 1. April 2019 / Occurrence of Pedunculate Barnacle, Octolasmis spp. in Blue Swimming.................

and the presence of tergum were observed. The length
and shape of calcareous plates were recorded. Barnacles have identified the species based on the description
of the morphological characteristics by Ihwan et al.,
(2013, 2014) and Jeffries et al., (2005). The good conditions of Octolasmis spp. specimens were selected for
the drawing process. All drawings were made by using
a compound microscope attached with Lucida camera.
The drawing measurements were in the nearest micrometers (µm). The photo of Octolasmis spp. were taken by
using research compound microscope (Nikon Eclipse
80i) with NIS-D Element programme.

Figure 2. Octolasmis angulate: whole body, (a) Scutum and (b) Carina (scale bar = 50µm)

2.4 Prevalence (P) and intensity (I) of Octolasmis spp.
The entire barnacles that have been collected
were analyzed for the prevalence and intensity for each
crab. The prevalence and intensity for barnacle found
from each gill crab according to their species. The calculation of prevalence (P) and mean intensity (I) were
calculated according to the formula of Margolis et al.,
(1982).

3. Results and Discussion
3.1 Morphological identification of Octolasmis spp.
found on P. pelagicus
There are four species of barnacle in the genus
Octolasmis spp. have been identified by comparing their
calcareous plates which including scutum and carina;
they are Octolasmis angulata (Figure 2), Octolasmis
warwickii (Figure 3), Octolasmis tridens (Figure 4), and
Octolasmis lowei (Figure 5). The prevalence and intensity of the barnacle infection are 92.3% and 49.46% respectively, which are 443 barnacles infect male and 200
barnacles infect female crabs. However, the distributions
of Octolasmis spp. on crabs were different. Octolasmis
angulata showed the highest prevalence (84.62%) followed by O. lowei (23.08%), O. tridens (30.77%), and
O. warwickii (23.08%). The different species showed
the different value of mean intensity, O. angulata (16.8)
and O. lowei (16.8) showed the highest intensity (16.8)
followed by O. warwickii (14.7) and O. tridens (1.2).
This study examined the barnacle as an ectosymbionts on blue swimming crab, Portunus pelagicus
from coastal area of Kuala Terengganu. From all barnacles that have been observed, four species of pedunculate barnacle genus Octolasmis were found and have
been identified by comparing their different shape of
scutum and carina. Usually, the morphology identification depends on the shape of calcareous plates (Jeffries
and Voris, 1996).

Copyright ©2019 Universitas Airlangga

Figure 3. Octolasmis warwickii: whole body, (a) Scutum and (b) Carina (scale bar = 50µm)

Figure 4. Octolasmis tridens: whole body, (a) Scutum
and (b) Carina (scale bar = 50µm)

Figure 5. Octolasmis lowei: whole body, (a) Scutum
and (b) Carina (scale bar = 50µm)

April 2019

3

Marina et al., / JIPK, 11(1):1-8

Octolasmis angulata has different shape of calcareous plates with long shape. It has capitulum oval
shape and partially calcified with 3 plate (Ihwan et
al., 2014). Octolasmis warwickii by having 5 capitular plates, 2 scuta, 2 terga and a carina (Voris and Jeffries, 1997). From the previous study, there were five
Octolasmis species recorded from portunid crabs in the
Northern Gulf of Thailand (Jeffries et al., 2005). The
following species are Octolasmis angulata, Octolasmis
cor, Octolasmis lowei, Octolasmis neptuni, Octolasmis
tridens, and Octolasmis warwickii. It were reported that
Octolasmis angulata was found on the gill chambers
of species of the families Calappidae, Palinuridae and
Portunidae from the Bay of Bengal, Arabian Sea, Malay Archipelago and off Madras. According to Jeffries
et al., (2005), 10 species of genus Octolasmis have been
recorded in South East Asia which attached on a living organism, Octolasmis angulata, Octolasmis bullata,
Octolasmis cor, Octolasmis lowei, Octolasmis neptuni,
Octolasmis tridens, Octolasmis warwickii and three unidentified species.
3.2 Site specificity of Octolasmis spp on P. pelagicus
The higher infestation rate of Octolasmis species was recorded by O. angulata and O. lowei, both
are 33.9%. The O. warwickii is 29.7% and O. tridens is
2.5%. Octolasmis angulata showed the highest number
of infestation on other areas such as carapace, legs, and
abdomen are 70 Octolasmis. For the gills area preference, gill number 4 (G4) showed the highest number of
Octolasmis angulata attached (n= 33). The Octolasmis
angulata are commonly attached in the range gill number 3 to 8 (G3, G4, G5, G6, G7, and G8). It majorly distributed on the distal part for both gills (Table 1; Figure
6).

areas such as carapace, leg, and abdomen also showed
the highest number of barnacle infestation, 188 barnacles. For gill area, gill number 2 (G2) was the only gill
that infected by barnacles which is 3. It distributed on
the distal, proximal and medial part for both gills (Table
2; Figure 7).

Figure 7. Gill preference of Octolasmis warwickii
For O. tridens, other areas such as carapace,
leg, and abdomen showed the highest number of barnacle which is 9 infested on it. For gill area, gill number
4 (G4) showed the highest number of O. tridens attachment, 4 barnacles. These barnacle species are commonly attached in the gill number 2, 3, 4 and 7 (G2, G3, G4,
and G7). It majorly distributed on the distal part for both
gill (Table 3; Figure 8).

Figure 8. Gill preference of Octolasmis tridens

Figure 6. Gill preferences of Octolasmis angulata
The total number of Octolasmis angulata infested on the gills were 149. For O. warwickii, other

4

Jurnal Ilmiah Perikanan dan Kelautan

For O. lowei, gill number 6 (G6) showed the
highest number of infestation, 42 barnacles. For gill
area, these barnacle species are commonly attached in
the range gill number 1 to 8 (G1, G2, G3, G4, G5, G6,
G7 and G8). These species are majorly distributed on
the distal part for both gills (Table 4; Figure 9).

JIPK. Volume 11. No 1. April 2019 / Occurrence of Pedunculate Barnacle, Octolasmis spp. in Blue Swimming.................

Figure 9. Gill preference of Octolasmis lowei

horseshoe crabs, coral, mollusks, sea snakes and fish
(Jeffries and Voris, 1996; Amber et al., 2014; Tan et al.,
2011). However, six barnacle species of the genus Octolasmis which are Octolasmis angulata, Octolasmis cor,
Octolasmis lowei, Octolasmis neptuni, Octolasmis tridens, Octolasmis warwickii were reported in crabs and
lobsters (Jeffries et al., 2005). There was more barnacle
on the gill of crabs. It could be more fouled because gill
was a better available to the settling of barnacle from
larval stages (Bastami et al., 2012). Our results showed
the distribution of the O. angulata, O. warwickii, O. tridens and O. lowei are randomly among the gill area.
For gill as site specificity study, the highest abundance
of barnacle was recorded in gill number 3 (G3) to gill
number 6 (G6). There were observed that only O. angulata and O. lowei were found at proximal, distal and
medial part.

Table 1. The distribution of Octolasmis angulata attached on the gill area of Portunus pelagicus.

Most species within the genus Octolasmis colonize on host species usually decapods. For mean intensity, both O. angulata and O. lowei showed the highest
mean intensity (16.8). The infestation occur entire body
of the P. pelagicus such as gill, abdomen and the carapace area. Earlier study reported that the O. angulata
has minimum value of intensity (11.0) in P. pelagicus
and O. warwickii has 14.3 % value of intensity (Kumaravel et al., 2009). The observation suggest that infestation rate of Octolasmis differ between species and
location.
Most barnacle species are typically very selective as to the site of attachment on the body of the
host (Voris et al., 1994). Sinduja et al., (2013) was
mentioned the stalked barnacles attach in various species and various region. The Octolasmis was reported
attached to many decapods and isopod crustaceans,

Copyright ©2019 Universitas Airlangga

Octolasmis tridens preferred the proximal and
distal part of gill only. The patterns of the distribution of
barnacle for this study are more to left and right part of
the gill area or proximal and distal part. In this study, it
showed certain Octolasmis spp. only specified to certain
part of the gill. Shazia and Javed (2017) was observed
that the Octolasmis was concentrated on the proximal
and medial parts of the gills rather than distal. The attachments of barnacle influenced by certain factor, for
example the current or water flow through gill (Voris
et al., 1994). In crabs, most of the water enters through
the openings at the bases of the chelipedes and through
pores situated in between walking legs. Then, water enter the crab hypobranchial chamber through opening at
the bases of thoracic appendages, this occurs as results
of pressure created (Shazia and Javed, 2017). The water flows was influenced the site selection of Octolasmis
spp. attachment. Mostly the Octolasmis was distributed

April 2019

5

Marina et al., / JIPK, 11(1):1-8

Table 2. The distribution of Octolasmis warwickii attached on the gill area of Portunus pelagicus.

Table 3. The distribution of Octoclasmis tridens attached on the gill area of Portunus pelagicus.

Table 4. The distribution of Octoclasmis lowei attached on the gill area of Portunus pelagicus

within branchial chambers of crabs because of the water flows into the branchial chamber. However, the attachment of Octolasmis on crabs also depend on the
behaviour. Walker (2001) was found that O. angulata
principally attached to the cuticle of the anterior chamber wall in the epibranchial space compared to the

6

Jurnal Ilmiah Perikanan dan Kelautan

gills of Charybdis callianasa. Charybdis callianasa behaviour is frequently buries itself into soft bottom in nature. Thus, the buried position make the
respiration current is likely to be reversed with water
entering through the epibranchial space and leaving
through the openings at the bases of chela and legs.

JIPK. Volume 11. No 1. April 2019 / Occurrence of Pedunculate Barnacle, Octolasmis spp. in Blue Swimming.................

4. Conclusion
In conclusion, four different species of Octolasmis spp. have been identified and described by comparing to the previous study. All samples that have been
identified up to species are O. angulate, O. warwickii,
O. tridens, and O. lowei. Basically, the distribution of
Octolasmis spp. did not show their specific gill attachment but the previous study showed the specific gill
attachment. Generally, site specificity for the Octolasmis spp. mostly depend on the water current and their
abundance according to the species which attach earlier.
Besides, their natural surrounding will affect the infestation rate.

Acknowledgments
We would like to thanks to Nurul Aleana Md
Said from School of Fisheries and Aquaculture Sciences (PPSPA) for their help during sampling and laboratory work. We also thank to Mr Shuhaimi, Mrs Wahidah
and Mrs Farizan from Institute of Tropical Aquaculture
(AKUATROP), Universiti Malaysia Terengganu for
their assistance in the laboratory.

References
Amber, K.G., Flint, M., & Paul, C. M. (2014). An antemortem guide for the assessment of stranded
Australian sea snakes (hydrophiinae). Journal
of Zoo and Wildlife Medicine, 45(4): 755-765
Bastami, A., Najafian, M., & Hosseini (2012). The distribution of the barnacle Epizoite, Chelonibitapatula (Ranzani) on blue swimmer crab, Portunuspelagicus. World Applied Science Journal,
20: 236-240.
Bhat, B. A., Ravichandran, S., & Allayie, S. A. (2011).
Influence of the eyestalk hormones on the metabolism and ionic regulation of the Crab Portunus pelagicus (Lineaus, 1857). Journal of Biological Sciences, 11: 203-209
DOF: Department of Fisheries. Fisheries Statistics of
Malaysia (2014). Fisheries Statistics of Malaysia, Fishery Economic Division, Malaysia.
Hamasaki, K., Obata, Y., & Kitada, S. (2011). A review
of seed production and stock Enhancement for
commercially important portunid crabs in Japan. Aquaculture International, 19: 217-235.
Ihwan, M. Z., Ikhwanuddin, M., & Marina, H. (2014).
Morphological distribution of Pedunculate

Copyright ©2019 Universitas Airlangga

Barnacle Octolasmis angulata (Aurivillius,
1894) on Wild Mud Crab Genus Scylla from
Setiu Wetland, Terengganu Coastal Water,
Malaysia. Journal of Fisheries and Aquatic
Sciences, 9: 366-371
Ihwan, M. Z., Ikhwanuddin, M., & Marina, H. (2013).
Morphological characteristic of pedunculate
barnacle attached on the gill of wild mud crab,
Scylla olivacea from Setiu Wetland Terengganu, Malaysia. In: The 22st Scientific Conference
of the Microscopy Society of Malaysia, Terengganu, Malaysia.
Ikhwanuddin, M., Azra, M. N., Talpur, M. A. D.,
Abol-Munafi, A. M., & Shabdin, M. L.
(2012). Optimal Water temperature and salinity for production of blue swimming crab, Portunus pelagicus 1st day juvenile crab. Aquaculture, Aquarium, Conservation & Legislation. 5:
4-8.
Jeffries, W. B. & Voris, H. K. (1996). A subject indexed
bibliography of the symbiotic barnacles of thegenus Octolasmis Gray, 1825 (Crustacea: Cirripedia: Poecilasmatidae). The Raffles Bulletin of
Zoology, 44: 575–592.
Jeffries, W. B., Voris, H. K., Naiyanetrand, P., & Panha,
P. (2005). Pedunculate barnacle of the Symbiotic genus Octolasmis (Cirripedia: Thoracica:
Poecilasmatidae) from the Northern Gulf of
Thailand. The Natural History Journal of Chulalongkorn University, 5: 9-13.
Kumaravel, K., Ravichandran, S., & Rameshkumar, G.
(2009). Distribution of barnacle Octolasmis on
the gill region of some edible crabs. Academic
Journal of Entomology, 2: 36-39.
Lai, J. C. Y., Ng, P. K. L., & Davie, P. J. F. (2010). A
revision of the Portunus pelagicus (Linnaeus,
1758) species complex (Crustacea: Brachyura:
Portunidae), with the recognition of four species. The Raffles Bulletin of Zoology, 58: 199237.
Margolis, L., Holmes, J. C., Kuris, A. M., & Shad, G. A.
(1982). The use of ecological term in parasitology. Journal of parasitology, 68: 131-133.
Nitiratsuwan, T., Nitithamyong, C., Chiayvareesajja, S.,
& Somboonsuke. (2010). Distribution of blue
swimming crab (Portunus pelagicusLinnaeus,
1758) in Trang province. Songklanakarin Jour-

April 2019

7

Marina et al., / JIPK, 11(1):1-8

nal of Sciences and Technology, 32: 207-212.
Rejeki, S. (2007). The effects of different water flow
rates on the survival rate of blue crab (Portunuspelagicus) zoea IV-megalopa stages. Journal of
Coastal Development, 10: 197-203.
Rohde, K. (1991). Ecology of Marine Parasite. University of Queensland Press, Queensland, Australia.
Shazia, R. & Javed, M. (2017). Pedunculate barnacle
Octolasmis (Cirripedia, Thoracica) on the gills
of two species of Portunid Crabs. International
Journal of Marine Science, 7(45): 432-438.
Sinduja, K., Raja, K., Saravanakumar, A., & Vijayakumar, R. (2013). Occurrence of goose barnacle
Octolasmis spp. infestation on commercial important crabs from parangipettai, Tamilnadu,
Southeast Coast of India. Wayamba Journal of
Animal Science, 578: 768-772.
Soundarapandian, P., Thamizhazhagan, E., & Samuel,
M. J. (2007). Seed production of commercially important blue swimming crab Portunus pelagicus (Linnaeus). Journal of Fisheries and
Aquatic Sciences, 2: 302-309.
Tan, A. N., Christianus, A., & Abdul-Satar, M. K.
(2011). Epibiont infestation on horseshoe crab
Tachypleus gigas (Muller) at Pantai Balok in
Peninsular Malaysia. Our Nature, 9: 9-15.
Voris, H. K., Jeffries, W. B., & Poovachiranon, S.
(1994). Patterns of distribution of two barnacle
species on the mangrove crab, Scylla serrata.
The Biological Bulletin, 187: 346-354.
Voris, H. K. & Jeffries, W. B. (1997). Size distribution,
and significance of capitular plates in Octolasmis (Cirripedia: Poecilasmatidae). Journal of
Crustacean Biology, 17: 217 – 226.
Walker, G. (2001). Some observations on the epizoic
barnacle Octolasmis angulate within the branchial chambers of an Australian swimming
crab. Journal of Crustacean Biology, 21 (2):
450-455.

8

Jurnal Ilmiah Perikanan dan Kelautan