Abandoned Shrimp Ponds Research Articles

Evaluation of shrimp-associated species in abandoned ponds in Mati City, Philippines

This study aimed to identify, characterize, and evaluate the biodiversity of shrimp-associated species in abandoned shrimp ponds, specifically assessing the trophic levels of bycatch species in Barangay Dahican, Mati City. Using a scoop net, researchers collected macrobenthic samples from Maitum, Lahusan, and Butuasan, finding 1,528 individuals with varying species compositions namely: Oreochromis niloticus (Nile tilapia), Coenobita cavipes (Land hermit crab), Canarium labiatum (Plicate conch), Rochia nilotica (Commercial top), Clithon oualaniense (Guamanian nerite), Cerithium coralium (Coral cerith), and Callinectes sapidus (Blue crab). Cerithium coralium was the most abundant species with 70% relative abundance, followed by Clithon oualaniense, with 29%. In contrast, the least abundant species were the Oreochromis niloticus and Canarium labiatum, with 1% relative abundance. Moreover, biodiversity indices revealed that Lahusan 1 (H' = 0.731; D=0.46) and Butuasan (H' = 0.714; D = 0.5) had higher biodiversity, whereas Lahusan 2 had the lowest (H' = 0.318; D = 0.15). In contrast, Lahusan 2 appeared to be the least diverse (H' = 0.318; D = 0.15). There were significant differences in terms of species abundance (df = 6, MS = 34.18, F = 6.02, P = 0.000) and none in terms of site locations (df = 3, MS = 18.71, F=2.08, P= 0.188). The study results showed that these associated species were mainly benthic and came from the nearby environment. Providing good management for the abandoned shrimp ponds in the area could mean reverting them to their original state to provide a habitat for other organisms.

Biodiversity, ecology, and bionomic aspects of Anopheles mosquitoes during the dry season in southern Sumatra

Abstract. Dalilah D, Anwar C, Syafruddin D, Saleh I, Pahlepi RI. 2024. Biodiversity, ecology, and bionomic aspects of Anopheles mosquitoes during the dry season in southern Sumatra. Biodiversitas 25: 1644-1654. South Sumatra and Lampung are western parts of Indonesia’s provinces that are endemic to malaria. This study aimed to determine Anopheles mosquitoes’ diversity, ecology, and biting behavior in both provinces. Understanding the diversity, ecology, and bionomy of Anopheles supports malaria elimination in endemic areas as well as surveillance of vectors in malaria-eliminated areas. The study was conducted during the dry season from June to July 2023. Mosquitoes were collected from southern Sumatra, Indonesia, i.e. Segara Kembang Village in Ogan Komering Ulu (OKU) District, South Sumatra Province, as well as Gayau and Durian Villages in Pesawaran District, Lampung Province. Adult mosquitoes were caught by human landing, resting, and cattle bait collection, while larvae were collected with dippers in the breeding habitat. A total of 4426 mosquitoes from 8 species of Anopheles were identified based on their morphology. The diversity index of Anopheles from all sample areas during this season was low (H’<1). Anopheles barbirostris s.l. and An. vagus found in habitats such as paddy fields and former fish ponds in OKU and Pesawaran District. As for abandoned shrimp ponds in Pesawaran, An. sundaicus s.l. and An. subpictus s.l. were the dominant ones. Mosquito An. sundaicus s.l seems to have a greater tendency to bite humans, whereas An. subpictus s.l was generally zoophilic. An. vagus was always present in all collection methods in all villages, with the greatest abundance in OKU. The finding indicates An. vagus appears to be the most variable in the behavior of all captured mosquitoes; therefore, in the future, it may be able to act as a major vector if transmission is not prevented.

Potential Use of Biomass Waste as a Sustainable Energy Source in the Future: A Case Study

Mangroves have been degraded and converted for decades due to a multitude of factors, ranging from human activity to natural perturbations such as disasters and global warming. Experiments were conducted to determine the impact of fly ash (FA) on the growth of Rhizophora apiculata Blume's (R. apiculate). A completely randomised design (CRD) was employed with D as the control, and nine treatment soil amendments were created from abandoned shrimp pond sediment with rubberwood fly ash (RWFA). These amendments were made by mixing three separate FA samples (A, B, and C) in the ratios of 75:25, 50:50, and 25:75, respectively (A1-A3, B1-B3, and C1-C3), using a total of 200 R. apiculata specimens. The experiment revealed that the addition of FA and its combination had a significant effect on promoting the growth of R. apiculate and improved nutrient availability and retention in the soil. The results of the experiment demonstrate that the effect of Fly Ash (FA) and its combination significantly influence the growth of R. apiculate, impacting the total heights and number of leaves. The most beneficial effect the results of the experiment demonstrate that the effect of fly ash (FA) and its combination significantly influence the growth of R. apiculate, affecting the total height and number of leaves. The most beneficial effects were observed when the optimal proportion of each type of soil amendment was used. The study holds substantial benefits: it introduces a method for improving the soil of shrimp farms through the utilisation of rubberwood fly ash (RWFA) and serves essential nutrients to mangroves. Moreover, implementing this plantation technique can aid in protecting against coastal erosion.

Vegetation structure and carbon stock of restored mangrove on abandoned shrimp pond in the International Mangrove Botanical Garden Rama IX, Thailand

Abstract. Wongprom J, Maneeanakekul S, Tara A, Chandaeng W, Duangnamon D, Rueangket A, Wechakit D, Wanthongchai P, Maknual C. 2023. Vegetation structure and carbon stock of restored mangrove on abandoned shrimp pond in the International Mangrove Botanical Garden Rama IX, Thailand. Biodiversitas 24: 5821-5830. The conversion of mangrove forest into shrimp aquaculture has severely impacted biodiversity and increased carbon emissions. Restoration program is thus urgently needed for such mangrove forests. In this study, we investigated the vegetation structure and composition, and biomass and carbon stock of restored mangrove on abandoned shrimp pond. Observation plots at restoration sites with age of 3-year-old (MF3) and 14-year-old (MF14) were established in the International Mangrove Botanical Garden Rama IX, Chanthaburi Province, Thailand and at abandoned shrimp pond (ASP) and protected mangrove forest (PMF) as reference sites. The diameters and heights of mangrove species were measured and identified in order to determine the vegetation structure, composition, biomass, and carbon stock. Soil samples from four soil depths, i.e. 0-15, 15-30, 30-50, and 50-100 cm, were collected to quantify the soil carbon stock. The results showed the good growth of Rhizophora stand planted at the restored sites with high vegetation biomass and carbon stock. This species also promoted species diversity, suggesting that Rhizophora spp. are suitable species for the restoration of abandoned shrimp pond. The vegetation biomass and carbon stock of MF14 (230.99 t ha-1 and 102.54 t C ha-1, respectively) was higher than that of PMF (133.84 t ha-1 and 64.94 t C ha-1, respectively). Higher vegetation and soil carbon stocks of the restored mangrove forest was positively influenced by the Rhizophora stand. However, the ecosystem carbon pool of PMF was higher (366.38 t C ha-1). This result indicates that the conservation of mangrove forest is significant to maintain the forest diversity, ecosystem function, and reducing carbon emissions, while mangrove forest restoration is essential to improve the vegetation structure and increase the soil and vegetation carbon stocks.

Recovery of Mangrove Ecosystem Carbon Stocks Through Reforestation at Abandoned Shrimp Pond in Southeast Thailand

Mangrove forests play an important role in the carbon cycle by sequestering atmospheric CO2and storing it as carbon in plant materials and sediments. We evaluated the ecosystem carbon stocks and carbon accumulation rates of an 18-year mangrove reforestation site located in abandoned shrimp ponds of Southeast Thailand. Consequently, carbon stocks in biomass and soil increased drastically through reforestation compared to those in nonplanted area (NPA). Soil carbon stocks at 1.0- and 2.0-m depth after 18 years were approximately 2.1 times and 1.8 times higher than those in NPA. Soil carbon stocks at 1.0-m soil depth increased gradually across the mangrove chronosequence over 18 years. Ecosystem carbon stocks at the 18-year site were 179.6 ± 40.5 Mg C·ha−1to 1-m soil depth and 325.0 ± 77.6 Mg C·ha−1to 2-m soil depth, which was higher compared to those in NPA [69.3 ± 8.0 Mg C·ha−1(1 m) and 157.8 ± 10.9 Mg C·ha−1(2 m)]. The ecosystem carbon stocks were lower than the global mean value, but the carbon accumulation rate had a comparatively high value. The total carbon accumulation rate after 18 years was 9.9 Mg C·ha−1·year−1to soil 1-m depth and 18.1 Mg C·ha−1·year−1to 2-m depth. Moreover, correlation relationships between soil carbon stock and physicochemical properties such as pH, electrical conductivity, redox potential, bulk density, elapsed year, and temperature in NPA and reforestation sites were confirmed. Therefore, the recovery of carbon stocks through mangrove reforestation in abandoned shrimp pond can contribute to blue carbon ecosystem restoration as nature-based solutions.

Soil carbon stock in different of mangrove ecosystem in Mahakam Delta, East Kalimantan, Indonesia

Mangrove forests serve as a buffer against sedimentation from the mainland into the sea, protect the area from coastal erosion, and prevent seawater intrusion in some ecological types of coastal environments. Additionally, because soil and below-ground biomass retain a significant quantity of carbon, they are essential for carbon sequestration. The current study seeks to estimate the soil organic carbon stock of mangroves associated with natural regeneration, mangrove rehabilitation areas and abandoned shrimp ponds, in Mahakam Delta, East Kalimantan, Indonesia. A 125-meter-long transect line was used to collect data, with three sampling points representing the length of the transect line. Each soil sample was taken at three different depths: 0-50 cm, 50-100 cm, and 100-150 cm. After that, the samples were taken to the laboratory for carbon analysis. The mangrove rehabilitation area had the highest bulk density at 8.64 gr/cm3, followed by natural mangroves along the river border at 7.67 gr/cm3, and abandoned ponds had the lowest at 7.16 gr/cm3. The rehabilitation area had the highest soil carbon stock at 1120 tons/ha, followed by natural mangroves along the riverside at 686 tons/ha and abandoned ponds at 383 tons/ha. In accordance with the study, mangrove rehabilitation regions had larger soil carbon stocks than natural regeneration along the riverside and abandoned ponds. In order to protect the ecologically significant mangrove ecosystem and minimize the effects of climate change, mangrove restoration and rehabilitation are necessary.

Anthropogenic influences on coastal environmental changes in the Mekong Delta: a study from Ben Tre Province, Southern Vietnam.

Low-lying coastal environments are highly dynamic and sensitive to natural as well as anthropogenic perturbations. Climate change, sea level rise, storms and tsunamis are the natural phenomena that affect the deltaic coasts in Southeast Asia in general and Vietnam in particular. The effects of these phenomena can be exacerbated by human activities such as mangrove deforestation, aquaculture and infrastructure development. Conversely, the low-lying coastal areas are important in the economic development of Southeast Asian countries. In the Vietnamese Mekong Delta, coastal areas have been affected by a number of factors, such as climate change, sea level rise, aquaculture, pollution and tourism-related activities in recent decades. The present study investigated shoreline changes, expansion of aquaculture ponds, soil salinity changes and salinity intrusion in the river systems along the coastal areas of Ben Tre Province in the Vietnamese Mekong Delta between 1998 and 2020 using satellite imagery and field data. Variations in erosion and accretion were found to be not unique along the coast of Ben Tre. There was a rapid expansion of aquaculture ponds between 1998 and 2015 and a slight decline since then. Soil salinity has been increased between 1998 and 2020; it is seen from recent satellite data that soil is becoming more saline in the inland areas of Ben Tre. Saltwater intrusion into the rivers of Ben Tre is considered associated with El Niño-La Niña conditions. It is suggested that reforestation of abandoned shrimp ponds in Ben Tre by mangrove vegetation can be effective as a bioshield against coastal hazards, such as sea level rise and shoreline erosion.

Species diversity and estimation of carbon stock in abandoned shrimp pond of mangrove ecosystem in East Kalimantan

The mangrove forest ecosystem plays an absorbent and carbon sink to reduce CO2 levels in the atmosphere, including in degraded mangrove areas. This research was conducted precisely on abandoned shrimp ponds in mangrove areas in the Mahakam Delta. Four different locations are locating on Sepatin ponds, ponds, ponds, and ponds Bayur headland. The purpose of this study was to estimate the above-ground carbon stock in abandoned shrimp ponds. Carbon stock measurement methods create a 125 m transect and quadrant divided into six plots at each location. These measurements were conducted on living vegetation and dead wood from felling vegetation. Measurement of above-ground biomass was done by measuring the tree diameter at breast height (1.3 m) on each tree diameter> 5 cm in radius quadrant plot 7 m. Vegetation has a diameter <5 cm categorized in seedling criteria and measured 30 cm from the ground within the quadrant plot radius of 2 m. The vegetation diversity experienced a succession calculated using the diversity index by calculating the dominance index, diversity index, and similarity index of vegetation. While the calculation of above-ground biomass accumulation using allometric equations according to the species. The results showed that vegetation analysis in the fourth study sites obtained a high dominance index value at each location. The study is inversely proportional to the value of diversity and similarity index. The highest total carbon stock at Tanjung Nipah location was 11.599 Mg C. Ha -1, followed by Sepatin 6.248 Mg C. Ha -1, Benati Dalam 3.579 Mg C. Ha -1, and lowest carbon stock at Bayur location 1.460 Mg C. Ha -1.

Photosynthetic characteristics and leaf litter production of mangrove forests in Trang, southern Thailand

The aim of this study was to investigate the photosynthetic performance and litter production of planted (PLA) and natural (NAT) mangroves in Trang, southern Thailand. Relative chlorophyll content and other photosynthetic parameters, such as photosynthetic efficiency of Photosystem II (Phi2), yield of non-regulatory energy dissipation (PhiNO), yield of non-photochemical quenching (PhiNPQ) and quenching due to non-photochemical dissipation of absorbed light energy (NPQt), and litter fall production were determined and compared between two mangrove stands. Measurements of photosynthetic parameters were made using PhotosynQ to assess the health of the community structure in both stands. The assumption of this study, namely that there would be no significant difference in any photosynthetic parameter measured between the two stands, was confirmed using t-test with unequal variances confirmed (P &gt; 0.05 for all). Changes occurred quarterly and in sites with different species. In terms of litter production, significant differences were found according to stand (P &lt; 0.001), season (P &lt; 0.05) and site (Sikao, F3,129 = 4.357, P &lt; 0.01; Kantang, F3,190 = 3.243, P &lt; 0.01). PLA stands demonstrated similar photosynthetic characteristics to NAT stands. This study established the effects of land use changes on PLA mangroves (planted in an abandoned shrimp pond). The overall significance of the study is in highlighting the positive outcomes of mangrove restoration, particularly in degraded mangrove stands due to land use change.

Assessing the Natural Recovery of Mangroves after Human Disturbance Using Neural Network Classification and Sentinel-2 Imagery in Wunbaik Mangrove Forest, Myanmar

In this study, we examined the natural recovery of mangroves in abandoned shrimp ponds located in the Wunbaik Mangrove Forest (WMF) in Myanmar using artificial neural network (ANN) classification and a change detection approach with Sentinel-2 satellite images. In 2020, we conducted various experiments related to mangrove classification by tuning input features and hyper-parameters. The selected ANN model was used with a transfer learning approach to predict the mangrove distribution in 2015. Changes were detected using classification results from 2015 and 2020. Naturally recovering mangroves were identified by extracting the change detection results of three abandoned shrimp ponds selected during field investigation. The proposed method yielded an overall accuracy of 95.98%, a kappa coefficient of 0.92, mangrove and non-mangrove precisions of 0.95 and 0.98, respectively, recalls of 0.96, and F1 scores of 0.96 for the 2020 classification. For the 2015 prediction, transfer learning improved model performance, resulting in an overall accuracy of 97.20%, a kappa coefficient of 0.94, mangrove and non-mangrove precisions of 0.98 and 0.96, respectively, recalls of 0.98 and 0.97, and F1 scores of 0.96. The change detection results showed that mangrove forests in the WMF slightly decreased between 2015 and 2020. Naturally recovering mangroves were detected at approximately 50% of each abandoned site within a short abandonment period. This study demonstrates that the ANN method using Sentinel-2 imagery and topographic and canopy height data can produce reliable results for mangrove classification. The natural recovery of mangroves presents a valuable opportunity for mangrove rehabilitation at human-disturbed sites in the WMF.

Assessing changes of mangrove forest in Bac Lieu Province using multi-temporal satellite images during 1988-2018

This study is done to determine the current status of mangrove forests (mangroves) in Bac Lieu Province over the years (1988, 1998, 2013 and 2018), assess the change in mangrove area over specific periods, and at the same time determine causes of disappear and recovery processes. Landsat 5-TM, 8-OLI remote sensing image and Maximum Likelihood Classifier - MCL method were used to classify and assess the changes in the area of mangrove forests in Bac Lieu Province over the period 1988-2018. The results of the image interpretation in 1988, 1998, 2013, 2018 and the overlapping of the above maps show the area of mangroves in Bac Lieu Province has increased continuously from 1988 to 2018. During the 30-year period from 1988 to 2018, the total mangrove area in Bac Lieu increased by 1,069.4 hectares, 1.5 times higher than the original. The recovery rate of mangroves was determined to be 64.3 ha/year, 2 times higher than their disappearance rate during this period (28,7 ha/year). The main reason to the disappearance of mangroves is the conversion from mangroves to aquaculture (accounting for 91.1%), coastal erosion (accounting for 7,9%). Mangroves are restored mainly from coastal seawater surface (accounting for 46,3%), from agricultural land (27.8%), planting mangroves in abandoned shrimp ponds or planting mangroves in combination with aquaculture (accounting for 25,8%).

Preservation and recovery of mangrove ecosystem carbon stocks in abandoned shrimp ponds

Mangrove forests capture and store exceptionally large amounts of carbon and are increasingly recognised as an important ecosystem for carbon sequestration. Yet land-use change in the tropics threatens this ecosystem and its critical ‘blue carbon’ (carbon stored in marine and coastal habitats) stores. The expansion of shrimp aquaculture is among the major causes of mangrove loss globally. Here, we assess the impact of mangrove to shrimp pond conversion on ecosystem carbon stocks, and carbon losses and gains over time after ponds are abandoned. Our assessment is based on an intensive field inventory of carbon stocks at a coastal setting in Thailand. We show that although up to 70% of ecosystem carbon is lost when mangroves are converted to shrimp ponds, some abandoned ponds contain deep mangrove soils (>2.5 m) and large carbon reservoirs exceeding 865 t carbon per hectare. We also found a positive recovery trajectory for carbon stocks in the upper soil layer (0–15 cm) of a chronosequence of abandoned ponds, associated with natural mangrove regeneration. Our data suggest that mangrove carbon pools can rebuild in abandoned ponds over time in areas exposed to tidal flushing.

Is aquaculture abandonment a threat to sustainable coastal resource use? – A case study of Andhra Pradesh, India, with options for reuse

The conversion of important ecosystems and land used for other purposes to aquaculture and abandonment after short-term use threatens coastal resources. The spatial extent and location of abandoned aquaculture farms were explored in this study based on land use change detection and trajectories in the Krishna District of Andhra Pradesh, India, as a case study using the Geographic Information System (GIS), satellite data, spatial analysis techniques, and field verification. Satellite image interpretation keys for abandoned aquaculture were identified. The brackishwater aquaculture area increased by 387% from 1990 to 2000, then decreased by 19% in 2006, and further decreased by 47% in 2009. As a result, 6648 ha of shrimp farms were abandoned in 2006. This number further increased to 13,493 ha in 2009. The introduction of the Penaeus vannamei culture in 2009 has increased the shrimp farm growth by 35% in 2015 and revived 11% of the unused aquaculture farms. Considering the rise and fall of the extent of shrimp farms, overall 30.6% of the shrimp farms were abandoned in 2015. Markov chain analysis indicates that the abandoned aquaculture area will be 11,512 ha in 2021 and that the conversion of agricultural land into shrimp farms continues. The soil characteristics of abandoned shrimp ponds and the water quality of source waterbodies near unused areas indicate the potential of the reuse for shrimp farming based on suitable management practices. Identification of the prior land use of abandoned shrimp farms such as mangroves, agricultural land, has given the options for reuse. Efforts need to be made to revive abandoned shrimp farms; otherwise, they may lead to unsustainable resource use in major shrimp-growing countries worldwide.

Microplastics in the surface sediments from the eastern waters of Java Sea, Indonesia

Background: This study aimed to investigate the abundance of microplastics in the eastern water of Java Sea. The study areas are well known for the high population and high industrial activities that can contribute to the plastic pollution. Methods: Microplastics were sampled from the surface sediments at five different stations representing different local activities: fish landing area (St 1), mangrove forest (St 2), abandoned shrimp pond (St 3), river mouth (St 4) and open sea (St 5). Results: Three types of microplastics were found; the most common was plastic fragments (54.34±6.39%) followed by fibers (41.45±4.59%) and films (4.21±3.90%). The highest abundance of microplastics was observed in the mangrove area (896.96±160.28 particles/kg), dominated with fragments and fibers. Films were found in greatest quantities in the fish landing area, but compared to the other types of microplastics, the abundance was much lower (80.73±37.62 particles/kg). Domestic wastes and fisheries activities were the main causes of the high microplastics in the study areas. Conclusions: The results of this study showed that microplastic pollution is a serious problem that needs to be paid attention not only from the government but also from the local people. Plastics management waste is needed.

Microplastics in the surface sediments from the eastern waters of Java Sea, Indonesia.

Background: This study aimed to investigate the abundance of microplastics in the eastern water of Java Sea. The study areas are well known for the high population and high industrial activities that can contribute to the plastic pollution. Methods: Microplastics were sampled from the surface sediments at five different stations representing different local activities: fish landing area (St 1), mangrove forest (St 2), abandoned shrimp pond (St 3), river mouth (St 4) and open sea (St 5). Results: Three types of microplastics were found; the most common was plastic fragments (54.34±6.39%) followed by fibers (41.45±4.59%) and films (4.21±3.90%). The highest abundance of microplastics was observed in the mangrove area (896.96±160.28 particles/kg), dominated with fragments and fibers. Films were found in greatest quantities in the fish landing area, but compared to the other types of microplastics, the abundance was much lower (80.73±37.62 particles/kg). Domestic wastes and fisheries activities were the main causes of the high microplastics in the study areas. Conclusions: The results of this study showed that microplastic pollution is a serious problem that needs to be paid attention not only from the government but also from the local people. Plastics management waste is needed.

Application of Remote Sensing Technology in Restoration of Mangrove Wetlands in Abandoned Shrimp Ponds in Vietnam

Application of Remote Sensing Technology in Restoration of Mangrove Wetlands in Abandoned Shrimp Ponds in Vietnam

The practice of hydrological restoration to rehabilitate abandoned shrimp ponds in Bunaken National Park, North Sulawesi, Indonesia

Djamaluddin R, Brown B, Lewis III RR. 2019. The practice of hydrological restoration to rehabilitate abandoned shrimp ponds in Bunaken National Park, North Sulawesi, Indonesia. Biodiversitas 20: 160-170. The world has lost a large extent of mangroves, while rates of recovery of these ecosystems from natural re-growth and restoration are slow. We developed a hydrological restoration technique to investigate the importance of hydrological modification in mangrove restoration success. Ecological Mangrove Restoration was adopted to restore abandoned shrimp ponds at Tiwoho, Bunaken National Park, North Sulawesi. Hydrological modification resulted in the creation of various mangrove sub-habitat conditions. These conditions remained unstable within the first three years and became relatively stable after seven years. Tidal inundation and soil surface salinity appeared to be the major factors controlling mangrove establishment and growth. All natural recruits and planted trees grew faster and produced more propagules/fruits within a short period of time after the normal physical conditions achieved. The restored site was covered by approximately 91.3 % of vegetation with the same canopy species composition as the natural stands. The practiced hydrological restoration method was simple, cost-effective and can help other practitioners in improving their mangrove restoration techniques.

Carbon dynamics and land use carbon footprints in mangrove-converted aquaculture: The case of the Mahakam Delta, Indonesia

Mangroves provide a number of important ecosystem services to humanity but their persistence is threatened from deforestation, conversion, and climate change. The Mahakam Delta was once among the largest mangrove forests in Southeast Asia comprising 2% of Indonesia’s total mangroves. Currently, about 62% of this extensive mangrove in the Mahakam Delta has been lost mainly due to conversion into aquaculture. To understand the impacts of mangrove conversion on carbon losses and therefore their values in climate change mitigation, we sampled 10 intact mangroves and 10 abandoned shrimp ponds to quantify: (1) the total ecosystem carbon stocks; (2) potential CO2 emissions arising from mangrove conversion to shrimp ponds; and (3) the land use carbon footprints of shrimp production. The mean ecosystem carbon stocks in shrimp ponds (499 ± 56 Mg C ha−1) was less than half of the relatively intact mangroves (1023 ± 87 Mg C ha−1). This equates to a potential annual emission factor over 16 years following mangrove conversion of 120 Mg CO2e ha−1 yr−1, which is similar with the total carbon loss from land conversion in freshwater tropical peat swamp forests. Inclusion of C losses from land use/cover change in a life cycle analysis (i.e., the land use carbon footprint) resulted in an estimated 2250 kg CO2-e emitted for every kg of shrimp produced in mangrove-converted ponds. Conversion of mangroves to shrimp ponds in the Mahakam Delta resulted in a carbon loss equivalent to 226 years of soil carbon accumulation in natural mangroves. Conservation of mangroves are of great value for inclusion in climate change mitigation strategies because of their large carbon stocks, the large carbon emissions generated from land use, and the potentially long period of time required to recover carbon stocks following abandonment.

Effects of Salinity on Survival and Growth of Gurami Sago (Osphronemus goramy, Lacepède, 1801) Juveniles.

Gurami Sago Osphronemus goramy (O. goramy) are an herbivorous freshwater finfish species native in Indonesia. This species has not yet been cultured commercially in brackish water. A 60-days study was conducted to evaluate the effects of salinity on survival and growth of O. goramy. Two independent experiments were performed to determine the effects of salinity on survival and growth of juvenile O. goramy, first one was to determine the median lethal salinity (MLS-5096 h) and second one was to assess the survival and growth at different sub-lethal salinities. In MLS-5096 h study 0.0, 4.0, 8.0, 12.0 and 16.0 ppt salinities were used to initially find out the salinity tolerance range. Accordingly, a definitive salinity tolerance test was done in next phase to find out exact median lethal salinity by directly transferring the test species to 13.0, 14.0, 15.0 and 16.0 ppt salinity for 96 h. The median lethal salinity of O. goramy was estimated at 14.0 ppt. In the second experiment, survival and growth of the O. goramy were recorded at salinities 4.0, 8.0 and 12.0 ppt along with 0.0 ppt as control during 60 days. Osigni goramy exhibited lowest final average weight at 12.0 ppt salinity and significantly highest at 4.0 ppt salinity. Highest SGR and weight gain were obtained at 4.0 ppt followed by 0 ppt, 8 ppt and 12 ppt salinity. All treatments were significantly (p<0.05). Survival rate of O. goramy varied between 76.45% (at 0.0 ppt) and 66.66% (at 12.0 ppt). The O. goramy grew and survived satisfactorily at 0.0 to12.0 ppt salinities, implying that the species can be cultured commercially in brackish water, in view of in Indonesia, there are many abandoned shrimp ponds.

Evaluation of Rhizophora Mucronata Growth at first-year Mangrove Restoration at Abandoned Ponds, Langkat, North Sumatra

Degraded mangrove areas can be restored and rehabilitated. In Indonesia, one of the main recommended of mangrove species for restoration of degraded was Rhizophora mucronata. The purpose of the study was to evaluate R. mucronata growth at first-year mangrove restoration at abandoned shrimp ponds, Pulau Sembilan village, Langkat, North Sumatera, Indonesia. The recovery area divided into three zones based on the salinity concentration, landward, middle, and seaward zones. The evaluation parameters of mangrove reforestation consist of seedling diameter and height, leaves number, and seedling growth rate. Results showed that 3 of 4 evaluation parameters of R. mucronata growth belong to landward zone, namely seedlings diameter, the number of leaves, and percentage of growth. By contrast, height R. mucronata seedlings dominated in the middle area. The study also found that the proper zone for mangrove restoration with R. mucronata was in the landward with 96% growth rate and 30 part per thousand salinity concentration. The present study, therefore, suggested that the recommended species for the degraded area was the prerequisite for successful mangrove restoration.