Fish Standing Stock at the Artificial Reefs ofPulau ... - seafdec.org.my

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* density/10m square 1 rare 1-2individual observed2 common 3 5 individuals observed3 abundant 6 10 individuals observedSmall (less than 30 cm) E.coiodes can be observed at the shallow end of the tyre reefs near theboundary to the coral reefs.Larger E. coiodes were observed at the boat reefs and the concreteartificial reefs. The number of fish observed were smaller as the size of each individual increasedat the artificial reefs. The mean number of individuals per reef type were high at the tyre reefcompared to the other reefs (Figure 2).Anypherodon leucogrammicus were observed to be high in number near the natural reefs and thetyre reefs compared to the other two reefs. Other resident fish observed were Chaetodontid andSweetlips but occurrence varied from each observation.(/)25.~(,)Q)0-(/)--20.!!2m 15 :J"0:~"0c10-0ci 5z~ nO.of individual~ nO.of species0~0 f..,0 ~ ~(,,0.§~ '
The artificial reefs observed varied in a number of aspects such as depth range, structurecomplexity and material used. Epinephalus sp. was observed in this study as this species showedno significant variation to depth as it can be observed throughout the different depth studied. Evenat the deepest depth (the boat artificial reefs) the small individuals can be observed. As this type offish has a predatory eating habit colonisation of the structure by algae, mollusc and otherencrustation may be of indirect impact to the fish. It might be dependent on other type of grazersand plankton feeders which are daily visitors or benthic feeders that hide in the reef. Most of thefish species observed near the artificial reef can be considered as predatory type (grouper, snapper)and herbivorous grazer type for example the parrotfishes were less in the deeper part of the reef.Plankton feeders or pelagic hunter group for example the rainbow runner Elegatis bipunnulataand the Trevally (Caranx sp.) observed to circle the water column above either just swimming orhunting.From all the species, Epinephalus coiodes can be considered the most abundant in this area andwere observed in a range of sizes. The sizes observed were from the large adults to smallindividuals (20 cm total length). All the different size individuals can be seen occupying the samearea. Pulau Payar as a whole may be acting as a trap for the larvae stages that then grow tojuvenilesand stay around Pulau Payar. The young may have drifted from another area or naturally producedaround the island and get trapped by the water current and reef structure around Pulau Payar.Further studies should be done on the juveniles production and aggregation around Pulau Payar.The knowledge of the life cycles and breeding season for the species may be useful to describe theproduction of the species here. The second most abundant grouper species is the Anypherodonleucogrammicus. This species were also observed in a wide range of sizes. The maximum sizeobserved was estimated to be nearly 1 m in length and the smallest size observed wasapproximately 0.06 m. Smaller size juveniles were not observed during the survey. The stock ofgrouper in the artificial reef ofPulau Payar was in the range between 15-35 kg per metre square,compared to the maximum catch by Omar et al. (1991) approximately 20 kg per sampling trip.Observation shows that any non-harmful material can be used as artificial reefs to aggregate andproduced fishes (Grove and Sonu, 1991). Production here is mainly described as the increase ofbody size and the increase in chances of fry production as the recruitment of new small juvenileswas not observed during the study. Increase in recruitment or overspill of young ones is consideredone of the major contribution of the artificial reefs to the marine ecosystems but a lot more studyshould be done to prove this in a quantitative form. Amarine ecosystem needs enough input so thatthe individual ecosystems can accumulate and reproduce. Reproduction and output of anecosystem relies on many factors, for example the number of matured individuals, reproductivecycles and food availability.The best type of artificial reef observed were boat reefs and tyre reefs according to the number andvariety of fish sizes aggregating around it. Compared to the concrete reefs both the reefs wereobserved to have more crevices and holes for juveniles to seek refuge compared to the concretereefs. Abdul-Razak and Ismail (1992) found that the mix type reef with extra structure and spacesaggregate higher numbers of species compared to plain single structure. Furthermore the boat
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Fish Standing Stock at the Artificial Reefs ofPulau ... - seafdec.org.my

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