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An investigation was accompanied in the rice field plots with developing an infrastructure of 30 m2 to ascertain the felicitous fertilization effects of the Nile tilapia (Oreochromis niloticus) and the common carp (Cyrpinus carpio) cultured along with the rice fish farming system in the plots. There were setting up three systems to assess the effect of fish species on tiller yield, regarding for fish species i.e. no fish stocking with rice (C), O. niloticus with rice (FT) and C. carpio with rice (FC). Each treatment of fish species cultured with different doses of fertilizer such as (T0) control: without any fertilization; (T1) with 100% recommended fertilizer (RF); (T2) with 75% recommended fertilizer (RF); (T3) with 10 ton compost fertilizer; (T4) with 5 ton compost fertilizer+75% RF, and rice culture with 5 ton compost fertilizer+50% RF. The maximum number of plant in the tiller were found in C. carpio (FC) species (7.02 no/tiller and 82.95 cm/tiller) whereas lowest in FT (6.40 no/tiller and 81.65 cm/tiller) during 75 DAT. In regards of fertilizer application, the highest values were observed in FC with an average of 31.71, 53.28 and 73.06 cm/tiller during 30, 40 and 60 DAT respectively, followed by F0 (31.92, 52.43 and 72.31 cm/tiller at 30, 45 and 60 DAT) and FT (30.28, 49.76 and 67.25 cm/tiller at 30, 45 and 60 DAT) respectively, in which there was found negative significant differences (P>0.05) among different treatments. The rice production in C. carpio fertilizer treatment T4 (7.30±1.86 kg/m2) was significantly higher than those of other treatments (7.16±2.78, 6.83±2.88, 6.67±1.44, 6.17±1.84 and 4.06±1.76 kg/m2 in treatments T5, T3, T2, T1, and T0 respectively). The yields of fish were significantly higher (P<0.05) in treatments T4, (11.70±3.86 kg/m2) than other fertilizer treatments T5 (11.25±3.56 kg/m2), T3 (10.85±5.76 kg/m2), T2 (10.80±5.55 kg/m2), T1 (9.90±4.66 kg/m2), T0 (4.78±3.48 kg/m2) and in FC and also compared to all other fertilizer treatments i

The integration of quality rice (Oryza sativa L), a globally important staple food crop with fish Nile tilapia (Oreochromis niloticus) and common carp (Cyprinus carpio) is deemed more profitable than a mono-crop culture of the rice. Thus, this study was undertaken to determine the best stocking density, fertilization application, feeding schedule, feeding rate, feed premix and their effects on nutrients uptake, weeds control as well as fish and rice production in rice-fish integrated farming system. A series of experiments were conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU) in Mymensingh, Bangladesh from December 2017 to December 2018. In randomized complete block design (RCBD) with three replicates. Each plot was 15 m2 and surrounded by elevated dikes of about 0.5 m height. Rice (BR dhan29) seedlings were transplanted from the nursery to the plots at alternative row spacing of 15 and 35 cm and a spacing of 20 cm within the rows. Common carp and Nile tilapia were released 20 days after transplanting (DAT) at an average weight of 25.32±0.81 g and 12.52±0.48g and 1:1 mixing ratio with stocking density of 6 fishes/m2. The study determined a stocking density of 6/m2 in 1:1 of carp and tilapia was the best stocking density. In experiment (II), each treatment of fish species cultured with different doses of fertilizer as follows (T0) control: without any fertilization; (T1) with 100% recommended fertilizer (RF); (T2) with 75% recommended fertilizer (RF); (T3) with 10t h-1of compost fertilizer; (T4) with 5t h-1of compost fertilizer + 75% RF, and (T5) rice culture with 5 t h-1of compost fertilizer + 50% RF. The outcome shows that T4 9.72±5.35provided the maximum yield, followed by T5 9.72±5.35,T3 9.63±6.66, T2 9.45±6.32, T1 8.08±3.86 and T0 4.00±4.56 kg/m2. However, in experiment (III) it was found that feed application for five days a week in morning and evening (0900-1800) has the best rice yield11.96 t h-1 and straw yield 6.63 t h-1.

Recently, Sancti Petri channel on the southwestern (SW) part of Iberian Peninsula has been experiencing urban, industrial, and vehicular expansion. Until recently, there have been only few published reports documenting the pattern of metal accumulation in this estuarine sediment. In the present study, trace metals such as Cu, Zn, Ni, Mn, Pb, Co, Cd, As, and Hg concentrations were analyzed from 69 sediment samples collected from 23 sampling sites of the Santi Petri channel. The magnitude of trace metal accumulation found as the following trend: Mn > Zn > Cu > Pb > Ni > Co > As > Cd > Hg. Spatial distribution pattern demonstrated overall decreasing trend of trace metal from Cadiz Bay mouth to the open ocean mouth, clearly correlative to the presence of anthropogenic inputs. Results of the principle component analysis (PCA) revealed that sediment metal chemistry of Sancti Petri channel is mainly regulated by the concentrations of Pb, Cu, Zn, and Ni; possible sources of those were from vehicular-related emissions. Pollution load index (PLI) and geo-accumulation index (I geo ) indicated overall low values. The study will stimulate improvement of our understanding regarding the pattern of accumulation of metals in the coastal sediments, and the recorded values of metals in the present study can be used as suitable reference for future studies.

Mangrove macroalgae produce substantial proportion of biomass, which contributes to the coastal ecosystems. Relatively less is known for the seasonal variation in the occurrence and biomass of mangrove associated macroalgae. Consequently, mangrove macroalgae epiphytic on the pneumatophores of Avicennia marina (Forsk.) Vierh., were sampled from the Miri estuary of Sarawak during the four seasons of Malaysia namely southwest monsoon, northeast monsoon, and two inter-monsoons to elucidate seasonal variation in the occurrence and biomass production of macroalgae. Over the sample period, 11 species of mangrove macroalgae were identified from 6 genera. Six of these species such as Caloglossa leprieurii (Montagne) J.Agardh, C. adhaerens R.J.King & Puttock, C. stipitata E.Post, C. ogasawaraensis Okamura, Bostrychia kelanensis Grunow and Dictyota sp. were found to be common in each sample time. Considering four seasonal samples, maximum frequency of occurrence was observed for C. ogasawaraensis (66 ± 10%) and maximum biomass was observed for B. kelanensis (248 ± 95 g m-2). Marked seasonal variations were observed in the frequencies of occurrence and the biomass for the most of the dominant macroalgal species. To the best of our knowledge this is the first time to report the seasonal pattern data for occurrence and abundance of macroalgae from the mangrove systems of Malaysia.

This baseline study was carried out to investigate the physicochemical factors such as pH, salinity, temperature, turbidity, total dissolved solids (TDS), total suspended solids and dissolved oxygen (DO), as well as nutrient (nitrate, phosphate, ammonium) concentrations and the level of heavy metals (Fe, Zn, Cu, Mn) in the surface water of the Miri estuary at four sampling times based on the four seasons of Malaysia. Results indicated marked temporal differences in each of the water characteristics measured (except ammonium), where DO level (mean: 3.6 mg/L) was found in a concern level. The principle component analysis (PCA) was applied to the hydrological and hydrochemical data set of the Miri estuary; results indicated that principle component 1 and principle component 2 explained 61.78 and 18.69%, respectively, of the total variance in the data set. Besides, results of PCA also indicated that the factors for water characteristics variations were mainly related to TDS, salinity, and Fe. The data presented here will serve as benchmark information, especially to the agencies related to the formulation of suitable policy on water quality in such areas.

Assessment of litterfall production is essential to ascertain the status of nutrient cycling and forest health. Sarawak, Malaysia, is endowed with numerous pristine and estuarine mangroves; however, research on primary productivity of these forests is scanty. Therefore, litterfall production in a pristine Sibuti mangrove of Sarawak was estimated using litter traps for one year (January–December 2013), and forest structure was studied through tree census. The forest was dominated by Rhizophora apiculata (relative density [RD] was 77.11%), followed by Xylocarpus granatum (RD was 16.92%) and other species (RD was only 5.97%). The annual dry weight of litterfalls was estimated to be 1640.82 g m−2, of which R. apiculata contributed 92.94%, followed by X. granatum (4.01%) and other species (3.05%). Leaves were the most abundant (57.21%) contributory component of litters, followed by propagules (11.89%), flowers (10.85%), twigs (8.56%), and stipules (8.45%). No significant correlations were found for total litterfall and its major components with climatic variables and forest structure. Total litterfall of R. apiculata and X. granatum did not show any seasonal variations. However, leaf litter of R. apiculata showed a significant seasonal variation between intermediate (January–April) and wet (September–December) seasons. The litterfall production of Sibuti mangrove forest is higher in comparison to other tropical mangroves of the world. The higher productivity of the forest could be due to nutrient availability, pristine nature, and stand maturity of the forest rather than climatic influences. The findings of the study suggest that litterfall production of the pristine Sibuti mangrove is not influenced by the variability of climatic factors.

Mangrove macroalgal assemblages can be used to assess the level of bioavailable metal for environmental monitoring. To date there have been very scarce information on influence of abiotic factors on the temporal variations in occurrences and biomass production of mangrove macroalgae and their use in environmental monitoring elsewhere. Consequently, present study examined influence of some abiotic factors on the temporal changes in occurrence and biomass production of macroalgae epiphytic on pneumatophores of Avicennia marina (Forsk.) Vierh., and accumulation of heavy metal (Cu, Zn, Fe and Mn) by some of these selected macroalgae in Miri estuary, Sarawak. Within a pneumatophore two vertical segments (apex and basal) were considered to estimate frequencies of occurrences and biomass of macroalgae considering 4 seasons of Malaysia namely southwest monsoon, northeast monsoon, and two inter-monsoon. Acid extracted metals (Cu, Zn, Fe and Mn) were measured using AAS (Atomic Absorption Spectrophorometry) in surface sediment, surface water and most dominant six macroalgal species. Eleven species of mangrove macroalge were recorded, of which 6 species were common throughout the study period. From this study, macroalgal species such as Caloglossa adhaerens, , C. stipitata, C. ogasawaraensis, Bostrychia kelanensis and B. anomala were considered to be the new records in the Malaysian mangrove ecosystems. Significant differences (ANOSIM and nMDS) were observed in regards to biomass production between assemblages of two vertical segments (apex and basal) of pneumatophores. In general, marked seasonal variations were observed in the frequencies of occurrences and biomass for most of the dominant macroalgal species; presumably because of high temporal variations of hydrological and hydrochemical factors including turbidity and nutrients of the estuarine water. Canonical Correspondence Analysis (CCA) indicated that turbidity were the main variable influencing biomass production of ma

This study was carried out to assess the fishery resources of the Sibuti River estuary, Sarawak, Malaysia. Data were collected from the study area for a period of one year in different seasons. The estuary is relatively species-rich and a total of 4675 individuals of 32 families from 60 species of fish (55), crab (four) and shrimp (one) were collected. Coilia dussumieri was the dominant species (22.63%) followed by Nemapteryx caelata (11.85%), Otolithes ruber (7.85%) and Ilisha elongata (5.80%). Marked seasonal variations were found among most of the hydrobiological factors; however, seasonal variations were not significant for the diversity indices such as Shannon–Wiener, Margalef and Evenness. The number of fish taxa caught in different mesh size gill nets was 1 inch (42 species) > 2 inch (36 species) > 4 inch (25 species), suggesting that smaller mesh nets are more suitable for assessing the diversity of fishery resources. SIMPER analysis showed that Coilia dussumieri was the most abundant species in the dry (10.3%) and intermediate (8.1%) seasons, whereas N. caelata was most abundant in the wet season (7.1%). Significant differences (ANOSIM and nMDS) were observed in the species community structure between dry–intermediate and dry–wet seasons; however, species compositions were not significantly different between intermediate and wet seasons. Canonical correspondence analysis (CCA) showed that most of the species assemblages were positively correlated with turbidity and chlorophyll a, followed by phosphate, nitrate and zooplankton density. The findings suggest that the Sibuti mangrove estuary is productive in terms of diversified fishery resources, which are influenced by the hydrobiological factors.

Mangroves have substantial roles to induce sedimentation in the vulnerable coastal regions, which subsequently helps to combat climate change induced impacts like sea level rise. Although Sarawak has numerous pristine estuarine mangroves, studies on the roles of these mangroves in regards to sediment deposition are scanty. Therefore, this study was carried out to determine the sediment accretion and accumulation pattern of pristine Sibuti mangrove using tiles and sediment traps from January to December 2013. Monthly average accretion and accumulation rate of sediments of this mangrove were 0.55 mm and 0.08 g cm-2, respectively. A total of 6.56 mm and 0.93 g cm-2 sediments were accreted and accumulated annually. Significantly positive correlation (r=0.794) was found for the monthly accretion of sediments with accumulation. Accretion and accumulation of sediments were also positively correlated with rainfall. Comparatively higher rate of accretion and accumulation of sediments were estimated in the months of wet season when the rainfall and tidal inundation duration were high. Erosion was found higher in the months of dry season when the rainfall was low. Seasonal variations were not found for sediment accretion as well as accumulation in the study area. The findings of the study suggest that the roles of this forest in regards to sediment accretion through retention is compatible with the predicted annual rate of sea level rise of 1.8 to 5.9 mm within 21st century by IPCC.