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| Articles
by
J.S. Bujang |
Total Records (
7 ) for
J.S. Bujang |
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S.M. Al-Barwani
,
A. Arshad
,
S.M.N. Amin
and
J.S. Bujang
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Incidences of hermaphroditism in green mussels (Perna viridis) were determined in four different areas (Sebatu, Port Dickson, Muar and Johor Bahru) along the west coast of Peninsular Malaysia. In Sebatu, 1000 specimens of green mussels were used for the visual determination of sex ratios. The male:female visual ratio was 1:0.79. Three hundred and seventeen individuals were also sexually identified using histology technique. Male to female ratio was 1:1.01. Two hermaphrodite specimens were recorded during the months of June and September, 2004. In Port Dickson, 319 specimens were visually sex-determined, the male: female ratio was 1.00:0.86. One hundred forty one were also histologically identified. Male: female ratio was 1.00:0.96. There was no hermaphrodite specimen encountered in this population. For the population of Muar and Johor Bahru, the entire specimen’s numbers were visually sex-determined first and later confirmed by histological procedure. The male:female ratio was 0.72:1.00 and 1.00:0.95. No hermaphrodite specimen was found at either site. The pooled samples from different months showed no significant seasonal deviation in the sex ratio from a 1:1 ratio (Chi-square test, p>0.05). |
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S.M.N. Amin
,
A. Arshad
,
J.S. Bujang
and
S.S. Siraj
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Age structure, growth, mortality and yield-per-recruit
of Acetes indicus were examined in the coastal waters of Malacca,
Peninsular Malaysia between February 2005 and January 2006. Monthly length
frequency data were analyzed using FiSAT software for estimating population
parameters, including asymptotic length (L�), growth co-efficient
(K) and exploitation rate (E) to assess the status of the stock. The L�
and K for males were estimated at 29.40 mm and 1.70 year-1
and for the females that were 42 mm and 1.20 years-1, respectively.
The growth performance index (φ’) was calculated as 3.16 and
3.33 for males and females. The growth pattern of males and females showed
positive allometric nature of growth (b>3, p<0.05). The maximum
life span (tmax) of males and females was 1.76 and 2.50 years,
respectively. Total mortality (Z) by length converted catch curve was
estimated at 4.15 year-1 for males and 3.50 year-1
for females. The rate of natural mortality (M) for males and females was
calculated as 2.65 and 1.91 year-1 and the fishing mortality
(F) was 1.50 and 1.59 year-1 for males and females, respectively.
The recruitment pattern of A. indicus was continuous throughout
the year with two major peaks. The exploitation rate (E) of males was
0.36 and that of females was 0.45. The maximum allowable limit of exploitation
(Emax) of males and females was 0.71 and 0.57 for the highest
yield. The exploitation rates were less than the predicted Emax
values of males and females. Thus, the stock of A. indicus was
found to be under exploited in the investigated area. |
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N. Saupi
,
M. H.Zakaria
and
J.S. Bujang
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This study was carried out to analyze the analytic chemical composition and minerals content of yellow velvetleaf (Limnocharis flava L. Buchenau) edible parts collected from waterways at Sebauh, Bintulu, Sarawak, Malaysia in early July 2008 using standard method of food analysis. The edible parts of L. flava high in total carbohydrate by difference (14.56±0.14%) and gross calorific value (343.26±9.75 kJ/100 g), but low in moisture (79.34±0.15%), ash (0.79±0.03%) and crude protein content (0.28±0.01%) in dry weight basis. However, the crude fat (1.22±0.01%) and crude fiber content (3.81±0.04%) were within the range of Malaysian leafy vegetables. The high concentration of K (4202.50±292.37 mg/100 g), Ca (770.87±105.26 mg/100 g, Cu (8.31±1.83 mg/100 g), Mg (228.10±15.26 mg/100 g) and Zn (0.66±0.05 mg/100 g) were found in edible parts of L. flava. The concentration of Na (107.72±17.15 mg/100 g) was much higher when compared to the recommended dietary allowances. Thus, the edible parts of L. flava provide good sources of minerals such as potassium, calcium, magnesium and copper. However, nutritive value analyzed should not be the exclusive criteria for judging the consumptive significance of the edible parts. Besides, others factors such as palatability should also be taken into consideration. |
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Z.C. Cob
,
A. Arshad
,
J.S. Bujang
and
M.A. Ghaffar
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The age, growth, mortality and population structure of Strombus canarium Linnaeus, 1758 were examined in the Johor Straits, Malaysia from January to December 2005. A total of 2088 conchs were sampled where females were more abundant than males with monthly sex ratio of 1.72±0.17 (N = 12). The estimated growth parameter showed higher asymptotic length (L∞) and growth coefficient (K) in females (L∞ = 70.20 mm, K = 1.50 year-1) compared with the males (L∞ = 69.30 mm, K = 1.20 year-1). This resulted in better overall growth performance of females (φ’ = 3.81) compared with the males (φ’ = 3.48). The growth pattern of females and males showed positive allometric nature of growth (b>3, p<0.05), with estimated maximum life span of 2.0 and 2.5 year, respectively. The recruitment pattern was continuous, displaying only a single major peak event per year. The estimated natural mortality rate (M) was 0.95 year-1 in females and 0.86 year-1 in males, while the total mortality rate (Z) was 2.56 and 2.72 year-1, respectively. The fishing mortality rate (F) was 1.61 year-1 in females and 1.86 year-1 in males, which were higher than the natural mortality rates, thus indicating an unbalanced position of the stock. In addition, the exploitation rate (E) was higher than the maximum allowable limit of exploitation (EMSY), which was a further indication of overexploitation. For sustainable utilization of the resource, serious efforts should immediately be taken in reducing the exploitation rates of S. canarium in the study area. |
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Z.C. Cob
,
A. Arshad
,
J.S. Bujang
,
W.L.W. Muda
and
M.A. Ghaffar
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Strombus canarium is a commercially important gastropod that has great potential for advancement into aquaculture. In this study, the metamorphosis response of Strombus canarium larvae to various metamorphosis cues associated with conch nursery habitat and to KCl and GABA, were tested. Bioassays were run as static, no choice experiment and adopting a continuous exposure approach. Strombus canarium larvae showed strong metamorphosis responses when sediment (i.e., conch nursery habitat sediment/SD-NU) and detrital substrata (i.e., Thalassia detritus leachate/T-LC) from their nursery habitat were used (p<0.05). There was no metamorphosis in treatments using sterilized conch nursery habitat sediment (SD-ST) and sediment taken from outside conch nursery habitat (SD-OT). Experiments using fresh macrophyte blades of Enhalus acoroides (EA), Thalassia hemprichii (TH), Halophila ovalis (HA) and Ulva (UL) and adult conditioned seawater (SD-SW) also showed negative respond. Conch larvae demonstrate active habitat selection during metamorphosis and no spontaneous metamorphosis was observed. Settlement in S. canarium is associative in nature where epibionts associated with conch nursery habitat could be the cue for the metamorphosis. However, the specific epibionts/inducers and mechanisms underlining the process were not studied and therefore are subjected to more detailed investigation. The use of KCl was comparable with treatments using natural inducers (SD-NU and T-LC), thus was suggested for application in hatchery spat production of the species. |
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A. Arshad
,
S.M. Nurul Amin
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G.T. Yu
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S.Y. Oh
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J.S. Bujang
and
M.A. Ghaffar
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The population structure, length-weight and length-length
relationships of Acetes vulgaris were examined based on 1141 specimens
collected in the months of June and July 2006 from Pontian, Johor Bahru.
The morphological characteristics of A. vulgaris were examined
and the result was found to be similar when compared with the previous
research. Mean length of males was 23.18 ± 2.95 mm while for females
was 23.91 ± 3.53 mm. The range of total length for the males and
females was 14.00-33.00 and 13.00-32.00 mm, respectively. The relationship
between the total length and body weight of A. vulgaris was W =
0.0178L2.6368 (r2 = 0.829) for males and W = 0.0082L2.9144
(r2 = 0.902) for females. The carapace length and total length,
relationship for males and females were CL = 4.1844TL + 2.3983 (r2
= 0.732) and CL = 4.0872TL + 1.8879 (r2 = 0.732), respectively.
The sex ratio of female to male was found to be at 1: 3.27 with the number
of males exceeded that of the females. |
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Z.C. Cob
,
A. Arshad
,
J.S. Bujang
and
M.A. Ghaffar
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This study was conducted to analyze variation in Strombus canarium larvae development, growth and survivals when cultured during wet (main reproductive period) and dry seasons. Larvae were reared at 200 larvae L-1 in filtered seawater (0.22 μm) and fed with Isochrysis galbana at 1000 cells mL-1 ad libitum. The culture environment was maintained at 29 ± 1°C, salinity of 30 ± 1 PSU and photoperiod of 12:12 light dark cycle. Growth of the larvae was described on a length-at-age basis using the modified Gompertz regression. There was high correlation in shell length-at-age relationship for both wet season (R2 = 0.99) and dry season (R2 = 0.98) culture experiments. The maximal growth rate (M) and survival rate (S) were higher for larvae cultured during wet season (M = 62.44 μm day-1, S = 14.36 ± 2.31%), compared with dry season (M = 43.05 μm day-1, S = 5 ± 1.15%). The maximal attainable larval size (a) was however lower during wet season (950.19 ± 66.93 μm shell length) compared with dry season (1343.05 ± 586.51 μm shell length), which might be due to significantly low larvae density in the latter. Further studies are needed to investigate variation in bio-chemical composition of the egg mass, which was suggested as the main reason for the differences. |
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