Christopher Kri U (2001) Colonisation and growth of marine
animals on artificial reefs at Batu Penyu, Talang-Satang National
Park, Malaysia. Hornbill 5:nn-nn
COLONISATION AND GROWTH OF MARINE ANIMALS ON
ARTIFICIAL REEFS AT BATU PENYU, TALANG-SATANG NATIONAL PARK,
MALAYSIA
CHRISTOPHER KRI ANAK UBANG1
SUMMARY
The artificial reefs at Talang-Satang National Park
were constructed for marine conservation using concrete reef balls.
Since 1998 about one thousand reef balls have been deployed around
the coast of Sarawak. This is the first reef ball project in Asia
and was instigated for conservation purposes. The National Park has
important turtle nesting beaches, and reef balls are used to stop
trawlers from trawling within the resting areas used by turtles
during the nesting season.
This study focused on the presence and absence of
easily visible marine life on or using the reef balls at an
artificial reef at Batu Penyu within Talang-Satang National Park,
and did not attempt to identify organisms to species level. It was
found that reef balls are colonised by a range of marine animals and
the colonisation rate is very encouraging. The reef balls were
tagged for future monitoring. Future studies should include
collection and identification to species level to compare the
diversity of artificial reefs with natural reefs.
Reef balls appear to be successful as a basis for
the growth of new coral reefs. For the purpose of conservation,
decisions on the material used should be based on comparative
studies of different types of artificial reefs.
INTRODUCTION
The artificial reefs at Talang-Satang National Park
were created in 1998 using reef balls. Reef balls are constructed
using cement with the same pH as salt water, using special mixtures
and micro silica. This ensures that reef balls mimic the natural
reef limestone and remain stable. Reef balls can be used to promote
regeneration of damaged reef areas, to anchor mooring and marker
buoys, and to create recreational SCUBA diving sites, improved fish
habitat and lobster nurseries. Reef balls are also useful to stop
trawling because they have sharp textured surfaces, which are
capable of ripping trawler nets.
The objective of this study is to collect
information on the presence and absence of marine organism living on
the reef balls deployed in 1998 at Talang-Satang National Park near
Batu Penyu, about two kilometres away from Pulau Talang-Talang
Besar. No previous research or monitoring programmes have been done
by the Forest Department on reef balls.
METHODOLOGY
Out of a total of 180 reef balls making up the
artificial reef, six reef balls of each size (small, medium and
large) were selected and tagged. Methods for random sampling were
considered, but proved impractical when diving.
Sessile animals A piece of wire mesh 50 cm x
50 cm was placed on the reef balls forming 25 squares each 10 cm x
10 cm. For hard and soft corals, sponges and barnacles, the
proportion of squares in which they were present was recorded. Where
a patch of coral was centred in one square but overlapped an
adjacent square, it was only counted once.
Mobile animals The numbers of individual sea
urchins, molluscs and fish seen on or in the reef balls or using the
reef balls (e.g. feeding on the surface) were recorded.
For this study only the large and easily identified
animals were recorded. The observation did not count bivalves, which
are encrusted with other marine life (e.g. barnacles) and difficult
to distinguished separately. No specimens were taken for
identification.
RESULTS
The number of sessile animals recorded is shown in
Table 1. The numbers for mobile animals seen are shown in Table 2;
many crabs and shrimps were seen, but it was impossible to count
them properly because they fled rapidly. No cuttlefish were
seen.
Table 1: Percentage of reef balls colonised and
average cover
Sessile animals |
% of reef balls colonised |
% of 10 x 10cm squares colonised |
Small |
Medium |
Large |
Small |
Medium |
Large |
Hard coral |
100 % |
100 % |
100 % |
21 % |
46 % |
56.7 % |
Soft coral |
83 % |
100 % |
66 % |
7.3 % |
32 % |
16 % |
Sponges |
83 % |
16 % |
83 % |
11.3 % |
0.3 % |
20 % |
Barnacles |
100 % |
100 % |
100 % |
72 % |
80 % |
68 % |
Table 2: Total numbers and average of invertebrates
and fish per reef ball
|
Total |
Average numbers per reef ball |
Small |
Medium |
Large |
Invertebrates |
Sea urchin |
24 |
0.6 |
0.83 |
2.16 |
Lobster |
4 |
0 |
0.33 |
0.33 |
Molluscs |
34 |
4.0 |
0.5 |
1 |
Nudibranch |
2 |
0.17 |
0 |
0.33 |
Fishes |
Butterfly fish |
8 |
0.33 |
0.5 |
0.66 |
Angelfish |
11 |
0.5 |
0.66 |
0.66 |
Snapper |
17 |
0.8 |
0.5 |
1.5 |
Grouper |
2 |
0.17 |
0 |
0.16 |
Sweetlips |
2 |
0 |
0 |
0.33 |
Puffer fish |
1 |
0 |
0 |
0.16 |
Parrot fish |
17 |
0.83 |
1.16 |
0.83 |
DISCUSSION
Method The method used is suitable for
sessile and slow moving animals but not good for lobsters and crabs
because they flee. There is also a problem of identifying early
stages of growth, so only adults were recorded. Because the reef
balls were tagged, it will be possible to repeat the survey in
future years and track colonisation and growth. This is the first
reef balls project in Malaysia, so no comparisons are available.
Information from Marine Fisheries Department in Sarawak on shipwreck
and tyre reef monitoring is also unavailable.
Colonisation of reef balls The results from
the study are very promising as there is visible growth of coral and
other marine life on the reef balls. After two and a half years, all
the reef balls studied had been colonised by hard corals, and
barnacles, and most of them by soft corals and sponges. The reef
balls are used by large numbers of crabs and lobsters, and typical
reef fish such as angelfish and butterfly fish.
CONCLUSIONS
Reef balls can be very effective for marine
conservation, as a wide range of marine animals use them, either
living on them or using them for shelter or as feeding grounds.
Although this study only looked at the presence and
absence of easily visible marine life on the reef balls, this
information will help in planning more detailed research in the
future. Specimens should be collected and identified to species
level to compare diversity with natural and other types of
artificial reefs. Long term monitoring studies of the tagged reef
balls would give information on the rate of colonisation and growth
of marine animals. Similar studies on other types of artificial
reefs, such as tyres, wrecks and building waste should be carried
out for comparison.
Reef balls are also effective for preventing
trawling, and are especially useful near turtle nesting beaches.
More reef balls could be deployed to build reefs for recreational
SCUBA diving, as they are used by attractive reef fish.
Reef balls appear to be successful as a basis for
the growth of new coral reefs.
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