Lake Laut Tawar Research Articles

Analisa Limbah Fosfor Kegiatan Keramba Jaring Apung di Danau Laut Tawar Aceh Tengah

Floating net cage activities can cause water quality to decrease. The feed remains and the metabolism of the fish from these activities produces nitrogen and phosphorus . The objective of this study is to obtain the calculation model and the amount of phosphorus released into the waters of Laut Tawar Lake as a result of floating cage activities. The resulting formula was Pw = (F x [P]p) – ((It – Io) x [P]i), where their variables were given feed (F), phosphorus concentration of feed ([P]p), the final weight of fish (It), the initial weight of fish (Io), and phosphorus concentration in fishes ([P]i). It can be used to predict the increase in phosphorus waste based on the increase in floating net cage area. The weight of tilapia increases exponentially with the day of cultivation in the equation Y = 12.70e0.02x and the goldfish followed the formula Y = 2.28e0.03x. Phosphorus in tilapia varies from 1.58% to 2.23% with an average of 1.97%. Goldfish contain 1.19 - 2.02% phosphorus, with an average of 1.52%. Goldfish growth was not optimal due to inadequate feeding, so without excessive feeding and did not generate phosphorus waste. The cultivation of tilapia releases 0.09 Kg P/m2 of phosphorus waste from floating cages .

EKSPLORASI PANGAN TRADISIONAL ACEH: KARAKTERISTIK IKAN DEPIK (Rasbora tawarensis) DAN PRODUK OLAHANNYA

Depik fish (Rasbora tawarensis) is an endemic freshwater fish typical of Lake Laut Tawar in Central Aceh. Gayo people usually buy depik fish in fresh or processed form in the form of dried depik and belacan depik. This research is a laboratory experimental study that aims to analyze the quality of depik fish and its processed products (fresh, dry and fermented depik fish). The parameters analyzed consisted of chemical analysis in the form of proximate analysis (moisture, ash, protein, fat and fiber content) and microbiological analysis by calculating the total plate count (TPC) of total mesophilic bacteria, lactic acid bacteria and fungi. The results showed that there were differences in the chemical and microbiological characteristics of depik fish with their processed products. Fresh depik has the highest water content, while dry depik has the highest fat and protein content. The highest ash content and fiber content were obtained at belacan depik. The highest total of mesophilic bacteria was obtained in fresh depik, while the highest total of lactic acid bacteria was obtained in fermentation depik. Fungal populations were only found in dry depicts and fermentation depik

Ecosystem approach applicability to sustain endemic fishes in Lake Laut Tawar, Aceh

Lake LautTawar is the only home for two endemic cyprinids, i.e. Rasboratawarensis and Poropuntiustawarensis, both are economically important species supporting food security and livelihood to local inhabitants. The present research was aimed to examine the applicability of EAFM, ecosystem approach to fisheries management in protecting endemic fishes in LLT. By referring to standard module, the domains and its indicators were ranked and weighted. Having given score to the domain, the composite domain and the sum of aggregation values of all domains, the performance of fishery management could be presented as flag model. Gap analysis was implied by contrasting EAFM’s recommendation against current achievement with refer to defined indicator. The applicability of EAFM to sustaining endemic fishes was assessed by means impact analysis under the scenario of three generic goals(1) augmenting the quality and quantity of habitat and sustainable utilization of fishery resources, (2) promoting higher socio-economic benefits, and (3) improving function and synergy among management institutions. The results showed that recommendations from EAFM’s model were all doable and that impact positively to sustaining endemic species. The challenges in implementation encompass authority, cooperation and coordination, stakeholders, invasive species and administration status of the lake.

The competition index and growth performance between tilapia (Oreochromis niloticus) and native fish spesies Laut Tawar Lake in polyculture system

The polyculture system provides great benefits in cultivation, including increasing the productivity of land aquaculture, utilizing leftover feed, and improve water quality. The aim of this study was to analyze the competition index and growth performance of tilapia (Oreochromis niloticus), depik (Rasbora tawarensis), lemeduk/tengadak (Barbonymus schwanenfeldii) and peres/nilem (Osteochilus kappenii) in the polyculture system. This research was conducted at Fish Seed Center (BBI) Lukup Badak, Pegasing District, Central Aceh Regency on May – June 2020. This study used a completely randomized design consisting of 4 treatments and 3 replications, namely treatment A control (tilapia 150 of fish in monoculture system), treatment B (tilapia: 112 fish and lemeduk: 38 fish), treatment C (tilapia: 112 fish, depik: 38 fish), and treatment D (tilapia: 112 fish, peres: 38 fish). The experimental fish were reared in a happa container with a cage system of size 0.5x0.5x1m. The results showed that tilapia reared in the polyculture system had a significant effect (P <0.05) on growth performance compared to monoculture system (treatment A). The competition index shows a negative value between treatments. The research indicated that the best experimental was treatment B (tilapia: 112 fish and lemeduk: 38 fish) and treatment D (tilapia: 112 fish, peres: 38 fish) can increase growth performance and biomass production in polyculture system. In conclusion that the application of the polyculture system of tilapia was able to increase the value of growth performance and there was no competition between experimental fish.

A mini review on characteristic of depik fish (Rasbora tawarensis) and its processed products

Depik fish (Rasbora tawarensis) is a tpical endemic freshwater fish of Laut Tawar Lake in Central Aceh, Aceh Province. This lake has become the pride of the Gayo community as a source of clean water for various needs, a source of livelihood for residents and a tourist destination. Laut Tawar Lake and depik fish have become the trademark of the city of Takengon, Central Aceh. However, it is unfortunate that due to several reasons such as environmental degradation, introduction of foreign fish, destructive fishing techniques, pollution and climate change globally, depik fish population is currently decreasing drastically. Even depik fish has been appointed as a fish with a threatened status. Studies on the existence of depik fish as local food, form of presentation and nutrition are still rarely carried out. This article tries to review the existence of depik fish and its processed products through several existing studies including classification, distribution, morphological and genetic characteristics of depik fish as well as processing and characteristics of processed products.

Estimasi Potensi Produksi Ikan Di Danau Laut Tawar Berdasarkan Morphoedaphic Index

Laut Tawar Lake is located in Aceh Tengah District is the largest lake in Aceh Province. The lake, located at an altitude of 1230 meters above sea level, produces about 13 species of freshwater fish. Fish depik (Rasbora tawarensis), eyas (Rasbora sp.), and relo (Rasbora sp.) are endemic species of Laut Tawar Lake. This study aims to estimate the potential of fish production based on the value of morphoedaphic index. The observation was conducted for one year, from October 2016 until September 2017. The measurement of electric conductivity value of lake waters was conducted on 7 (seven) stations selected purposively in the lake area about 5870 hectares. The results showed that morphoedaphic index value of Laut Tawar Lake ranged from 5.10 to 7.84 with an average of 6.14. Potential of fish production in the lake is 33.47 kg/ha/yr with total potential of fish production of 196.49 ton/yr. The value shows a decrease of 10.93 kg/ha/yr over a period of 22 years. This decrease is caused by changes in morphometry parameters and water quality of Laut Tawar Lake.

Trend of rainfall over Indonesian major lakes from tropical rainfall measuring mission data

Establishing patterns of natural variability of water resources in lakes is important for water management. However, the availability of reliable data often becomes obstacles, especially in ungauged regions. Rainfall products from Tropical Rainfall Measuring Mission (TRMM) potentially fill this gap. The aim of this study is to assess the trend of rainfall over Indonesian major lakes using TRMM rainfall estimates to investigate the natural variability of rainfall over the lakes. TRMM 3B43 monthly data over the period of 1998–2017 obtained from Giovanni data portal maintained by NASA were used to assess the trend of rainfall over Indonesian major lakes. Rainfall correlation with El Niño-Southern Oscillation (ENSO) variability was also investigated using Southern Oscillation Index (SOI) and Multivariate ENSO Index (MEI). Trend analysis was carried out using Mann-Kendall test. Rainfall depths over Lake Laut Tawar in Sumatra tend to gradually decline, which is confirmed by the Mann-Kendall test. Result of the test of rainfall over all other investigated lakes on Kalimantan, Sulawesi, Papua, and Java indicate no trends except for that of Lake Paniai on Papua, which indicates an increasing trend.

A mini review on endemic and threatened fish Rasbora tawarensis in Lake Laut Tawar, Indonesia

Rasbora tawarensis or locally name Depik is an endemic and threatened fish species occurred in Lake Laut Tawar, Takengon City, Aceh Province, Indonesia. The population of the fish has been decreased over the years by over fishing, habitat perturbation and present of alien fish species in the Lake. Therefore, the conservation program is crucially needed, for this purposes the intensive studies have been conducted from 2009 to 2018. This paper presented the latest and previous findings on the bioecology, distribution, reproduction, feeding habits, genetic and breeding of this species.

AcehSeis project provides insights into the detailed seismicity distribution and relation to fault structures in Central Aceh, Northern Sumatra

For the first time a dense seismic network (AcehSeis) consisting of 30 short-period seismic stations was installed for 10 months from July 2014 in order to record crustal earthquakes in Central Aceh, Northern Sumatra, following the hazardous earthquake with magnitude Mw. 6.1, July 2nd, 2013. The objective of this research is to investigate the active fault characteristics derived from local earthquake data combined with a digital elevation model. The network recorded more than 1790 local events occurring along the main Great Sumatran Fault (GSF) and its secondary faults. Local earthquakes with azimuthal gap angles greater than 180° were excluded to avoid non-unique earthquake locations. Therefore from all recorded earthquakes, 1127 local earthquakes were used for further seismological analysis. A method of simultaneous earthquake relocation and 1D velocity determination was applied to obtain better location of earthquakes. The output of the first relocated seismicity was then relocated again by using a double difference relocation method. After relocation, earthquakes are concentrated in a narrow zone along the active fault, indicating the reliability of the earthquake location. We then determined the focal mechanism of earthquakes, based on the first polarity picks.The seismicity distribution correlates with the well-known GSF and its main secondary faults. Earthquake locations also clearly revealed several active segments which include the Batee, Beutong, Tangse-Geumpang, Lampahan, Aceh and Seulimeum, and Nisam faults. Also less-known faults as the Pamue and Atu Lintang-Peusangan faults are imaged. In Northern Aceh an unknown earthquake cluster associated with an active fault, the Nisam Fault was detected, which is also visible in the topography. The seismicity along GSF is offset at around 96.7 E, constrained by the nearly N-S striking Atu Lintang-Peusangan Fault confirming the segmentation of GSF at this longitude. The Aceh segment and the Seulimum Fault in the northernmost region of the network are both active and clearly imaged by the seismicity. The Pamue and the Lampahan Faults seem to be the splay of GSF as indicated by identical strike direction as the GSF. The Lampahan fault is characterized by NW-SE seismicity lineation, which is in agreement with the focal mechanisms. The Laut Tawar Lake could be a part of the Lampahan Fault that is also offset at ∼96.7 E at the line of the Atu Lintang-Peusangan fault. The Burni Geureudong Fault on the other hand strikes ENE-WSW which suggests a conjugate fault of the Lampahan Fault.

Identification and stocking density of elements phosphate indigo system for fish farming cages nets floating in freshwater district Laut Tawar, Aceh Province

Lake Laut Tawar is located in Aceh district of Aceh province. The lake were used by the community as a livelihood by making a Cages. One of the elements that influence the fish growth is an element Phosphate (PO4) and other such as, pH, nitrate-nitrite, temperature and others. The lake has undergone changes caused by the use of commercial feed. The sampling locations based on the environmental setting by using method "purposive sampling" from January to May. The results was found of 0.1407 mg/L phosphate with fish expenditure amounting to 23728.61 ton / year using cages of net with number as 92, stocking density at 48,950 of fish and marine area 19.77 Ha. However the standard classes showed is under class II Regulation with No. 82 Year 2001 3400, solid lowest stocking cages tail on the size of 2.5 x 2.5 x 3M (spacious, 181m3) with post-harvest fish expenditure amounted to 1,214 tons of fish/year, the highest 9,250 cages tail on the size e of 5 x 5 x 3m (spacious 123m3) with fish expenditure by 2,800 tones of fish/year. While the results of feed conversion and Phosphate content is 12.70% with the Feed Conversion Ratio (FCR) was 1,635 and 1,491.

Current research on endemic and threatened freshwater fish ( Rasbora tawarensis ) in Lake Laut Tawar, Indonesia

Current research on endemic and threatened freshwater fish ( Rasbora tawarensis ) in Lake Laut Tawar, Indonesia

ANALISIS KADAR PROTEIN IKAN DEPIK (Rasbora tawarensis) DI DANAU LAUT TAWAR KABUPATEN ACEH TENGAH (Protein Content Analysis of Depik (Rasbora tawarensis) In Laut Tawar Lake Aceh Tengah)

This study aimed to determine protein content of depik (Rasbora tawarensis) fish collected from fish culture in Laut Tawar Lake, Aceh Tengah. Protein content in fish was analyzed using Kjehdal method with two replications. The result showed that average protein content of depik fish was 15.29%. Based on the result, it could be concluded that protein content of fish depik from Laut Tawar Lake is 15.29%.

Description of Depik Fish (Rasbora Tawarensis) Lipid Content in Laut Tawar Lake Aceh Tengah

This study was aims to determine the fat content of depik fish (Rasbora tawarensis) collected from Laut Tawar Lake Central Aceh. The samples used were fresh fish from traditional catching around Laut Tawar lake with the weight of 12.45 and 12.74 gram. The samples were analyzed by Soxhlet method with two repetitions. The result of this study showed that the fat content of depik fish was 6,50%. It can be concluded that depik fish from Laut Tawar lake Central Aceh had average of fat content of 6,50%.Key words: Rasbora tawarensis, Laut Tawar, Aceh Tengah

Morphometric Variations of Rasbora Group (Pisces: Cyprinidae) in Lake Laut Tawar, Aceh Province, Indonesia, Based on Truss Character Analysis

The genetic variation of Rasbora group in Lake Laut Tawar has been reported previously, however information on morphometric variations of this Genus was not available. Hence, the objective of the present study was to evaluate the morphometric characters of Rasbora group in Lake Laut Tawar, in order to contribute useful information on the biology of this important fish. The truss morphometric method was utilized in this study. A total of 45 samples of Depik, 42 samples of Eas and 44 samples of Relo were used in this evaluation. Eight homologous landmarks were determined along the outline of the fish, and based on these landmarks, 14 characters or linear measurements were recognized. Discriminant function analysis was employed to distinguish the fish sample. The results showed that the truss morphological characters could highlight the high differentiation between Relo and the other two groups, and the closeness of Eas and Depik. The morphometric data strongly indicated that Eas and Depik should be regarded as a same species, Rasbora tawarensis , and Relo may be considered as a cryptic species. This finding is in agreement to the genetic data which was published previously.

DNA Barcoding of Freshwater Fishes from Lake Laut Tawar, Aceh Province, Indonesia

Background. on a short standardized segment of the genome. The main objective of the barcode of life project is to provide a database of genetic sequences which can be used as a tool for universal species identification.&#160; Indonesia has at least 1300 freshwater fish species, however unfortunately no species has been barcoded as yet.&#160; In the presently reported study, we subjected to barcoding a total of 14 species of freshwater fishes from Lake Laut Tawar, Indonesia. Materials and methods. On average, 10 random samples from each species were processed for DNA analysis. Approximately 655-bp were amplified from the 5&#8242; region of the mitochondrial cytochrome C oxidase subunit I (COX1) gene. All obtained sequences were edited and aligned using MEGA 4.0 program. Nucleotide divergence among sequences was estimated based on Kimura 2-parameter distances. Unique haplotypes were determined using DnaSP Version 5.10.02 software, and the genetic relations among haplotypes were assessed by constructing a phenogram using the neighbour-joining method Results. A total of 31 haplotypes from 14 freshwater fish species were produced in this study. The read lengths were 626-bp, where 259 sites were polymorphic, 254 sites parsimony informative, and five singletons. No stop codons, deletions, or insertions were observed in any of the sequences.&#160; The nucleotide distance between species ranged from 7.1%&#8212;between Puntius brevis (Bleeker, 1850) and Poropuntius tawarensis (Weber et de Beaufort, 1916)&#8212;to 30.4%&#8212;between Channa gachua (Hamilton, 1822) and Homaloptera sp.&#8212;indicating that P. brevis and P. tawarensis are very closely related. Conclusion. >This study confirms the utility of COX1 gene in accurate identification of 14 species of freshwater fishes from Lake Laut Tawar, however, three species could not be identified to species level namely Rasbora sp. (local name: relo), Homaloptera sp. (ilie) and Clarias sp. (mud). It is suggested that future studies should incorporate morphometric methods to resolve the taxonomic status of these undetermined species.

Komunitas fitoplankton di perairan Danau Laut Tawar Kabupaten Aceh Tengah, Provinsi Aceh

Abstract. The aims of the present study was to evaluate community structure and biomass of phytoplankton based on the depth stratification in the waters of Lake Laut Tawar. Sampling was conducted during March and April 2010. The results showed that 43 species of phytoplankton belonging to five classes were found in Lake Laut tawar. The most common class was Chlorophyceae with 20 genera, followed by Bacillariophyceae (diatoms) by 9 genera, Cyanophyceae (10 genera), Dinophyceae (2 genera), and Euglenophyceae (2 genera). The highest species composition was found at II with 15 m depth (24 genera), while the highest abundance of phytoplankton was occured at station with 10 depth (155600 cells/l), while the lowest abundance was obtained at 15 depth (12745 cells/l). Overall the phytoplankton population in Lake Laut Tawar was dominated by Bacillarophyceae. In addition, the diversity index of phytoplankton was in moderate level (2.34), while the evenness index was ranged from 0.43 to 0.87, indicate the distribution of the individuals of each species was varied, however there was no predominant species detected.Keywords. Phytoplankton, structure community, Laut Tawar Lake.

Keragaman jenis dan persen penutupan tumbuhan air di ekosistem Danau Laut Tawar, Takengon, Provinsi Aceh

Abstract. Primary production in freshwater can be observed with the existing of aquatic plants includes micro and macrophyte. The study of aquatic plant is necessary due to the plant has important in aquatic environments, such as providing habitat, spawning ground, feeding ground, and nursery ground for aquatic biota. This study was conducted in June 2012, and the purposes were to identify species of aquatic plants and their percent cover in Lake Laut Tawar, Takengon. Sampling were conducted using quadrate transects of 0.5 x 0.5 m2, and the every transect was divided into 25 sampling points. A total of 10 species of aquatic plants were found and there were divided into four groups based on their morpho-ecology i.e. emergent, free floating, free submerged and rooted with floating leaves. Of these, emergent group was the most predominant (six species), followed by free floating (two species), free submerged (one species), and rooted with floating leave (one species). Hydrilla verticillata (free submerged group) and Eichhornia crassipes (free floating group) had the highest percent covers and density.

Genetic variation and taxonomy of Rasbora group (Cyprinidae) from Lake Laut Tawar, Indonesia

There were three presumed form of Rasbora found in Lake Laut Tawar, i.e. Depik, Eas and Relo. However, their phylogenetic status was remaining unclear. For this purposes the genetic data were utilized to resolve the taxonomic ambiguity of Rasbora group in Lake Laut Tawar. Approximately 655-bp were amplified from the 5′ region of the mitochondrial cytochrome oxidase subunit I (cox1) gene using the primer pairs (Fish F1 and Fish R1). A total of 14 haplotype sequences were produced from the ingroup where haplotypes 1 to 8 were shared by Eas and Depik, and haplotypes 9 to 14 were belonging to Relo. The genetic divergence varied from 0.2 to 9.6% i.e. between Eas and Relo, 9.6% and between Depik and Relo, 9.5%. The genetic data strongly indicated that Eas and Depik should be regarded as the same species of Rasbora tawarensis.

Length-weight relationships and condition factors of two threatened fishes, Rasbora tawarensis and Poropuntius tawarensis, endemic to Lake Laut Tawar, Aceh Province, Indonesia

Summary Studied were the length-weight relationships (LWRs) and condition factors of two threatened species, Rasbora tawarensis and Poropuntius tawarensis, endemic to Lake Laut Tawar. The objective of the present study was to establish baseline data on LWRs of the two endemic fishes. The growth pattern for both species was predicted using a Linear Allometric Model (LAM) of length-weight relationship and Fulton’s condition factor (KTL) as well as Relative Weight (Wr). The b value of R. tawarensis was relatively similar between females and males, while the b value of female P. tawarensis was slightly higher than in males. Nevertheless, both R. tawarensis and P. tawarensis showed an allometric negative growth pattern. The average KTL value of R. tawarensis was 1.85 and 1.73 for females and males, respectively, while P. tawarensis had values of 2.44 and 2.41 for females and males, respectively. In addition, the average Wr values of R. tawarensis were 98.9 and 100.45 for females and males respectively, while 102.30 for female and 102.96 for male P. tawarensis, indicating that the condition factors of P. tawarensis were higher than in R. tawarensis.

Spawning seasons of Rasbora tawarensis (Pisces: Cyprinidae) in Lake Laut Tawar, Aceh Province, Indonesia

BackgroundRasbora tawarensis is an endemic freshwater fish in Lake Laut Tawar, Aceh Province, Indonesia. Unfortunately, its status is regarded as critical endangered with populations decreasing in recent years. To date no information on the spawning activities of the fish are available. Therefore, this study provides a contribution to the knowledge on reproductive biology of R. tawarensis especially on spawning seasons as well as basic information for conservation of the species.MethodsMonthly sampling was conducted from April 2008 to March 2009 by using selective gillnets. The gonadosomatic index, size composition and sex ratio were assessed. The gonadal development was evaluated based on macroscopic and microscopic examinations of the gonads.ResultsThe gonadosomatic index (GSI) varied between 6.65 to 18.16 in female and 4.94 to 8.56 for male. GSI of the female R. tawarensis was higher in March, September and December indicating the onset of reproductive seasons, the GSI and oocyte size being directly correlated with gonadal development stages. Although, a greater proportion of mature male than female was detected during the study, the sex ratio showed that the overall number of female was higher than male. The ovaries had multiple oocyte size classes at every stage of gonadal development, thus R. tawarensis can be classified as a group synchronous spawner or a fractional multiple spawner.ConclusionThe spawning seasons of R. tawarensis were three times a year and September being the peak of the reproductive season and the female was the predominant sex. This species is classified as a group synchronous spawner.