Freshwater Aquaculture Development Research Articles

PENGARUH MEDIA TERHADAP PRODUKTIVITAS CACING SUTERA (Tubifex sp)

Silk worms (Tubifex sp) is one of the natural feeds that are the main needs of larvae because they have more complete and complex nutrition compared to artificial feed. The existence in nature that is uncertain and very fluctuating makes silkworms difficult to obtain. To maintain its availability, it is necessary to conduct research and technological development in cultivation, especially finding out the type of culture media that is effective for reducing silkworms. Padang Jaya District, North Bengkulu Regency. This study aims to determine the best culture media composition to increase silkworm prodoktivity. This research was carried out at the Freshwater Aquaculture Development Center (BPBAT) of Bengkulu Province, Sido Luhur Village, Padang Jaya District, North Bengkulu Regency. In April – May 2019, using a Complete Randomized Design (RAL) consisting of 4 treatments and 4 repeats. Treatment A (pond mud 10%), B (pond mud 50% + chicken manure 20% + palm waste 30%), C (pond mud 50% + chicken manure 25% + palm oil waste 25%), D (pond mud 50% + chicken manure 30% + palm oil waste 20%). The variables observed during the study were absolute weight, organic matter content of the medium, water quality including temperature, and pH. The data was analyzed using fingerprint analysis and continued with the BNT test of 95% confidence level. The results showed that the influence of media on the productivity of silkworms (Tubifex sp) had a significantly different effect on the productivity of silkworms. It was concluded that treatment D is the media with the best composition to increase the productivity of silkworms with an absolute growth of 10.06 grams or 16.77%. The best C/N ratio was obtained by D media of 48.75.

Status of Freshwater Aquaculture in Gujarat: A Trend Analysis and Potential

This study was undertaken during 2022 in the Regional Research Center of ICAR-Central Institute of Freshwater Aquaculture, Anand, Gujarat, India to study the present status and potential in the development of freshwater aquaculture in the state of Gujarat. The present seed production (2608.37 million fry) and Inland fish production (0.158 MT) in Gujarat is forecasted to reach 3100 million fry and 0.22 MT in 2030; 4600 million fry and 3.14 MT in 2050, respectively. The Regional Research station of ICAR-CIFA had contributed significantly in promoting aquaculture by imparting skill training and providing technical backup to fish farmers. Authors argue that in order to further develop freshwater aquaculture value chain, concerted efforts are required to disseminate technology packages for fish breeding and seed rearing, semi-intensive culture practices, diversified fish farming, scientific management (fish feed and nutrition, water quality and fish health), ornamental fish farming, pearl production and cluster-based fish farming. However, successful implementation of suggested points will be depending on the sustainable adaptive capacity of the freshwater aquaculture producers, entrepreneurs, strategies and planning of policy makers and line departments of various state departments, input dealers and buyers in the state of Gujarat. Hence, they need to be supported in terms of skill, policy and market towards establishing a vibrant fish value chain. Therefore, adoption of BMPs, nurturing entrepreneurs, aggregating farmers and strengthening extension services are recommended.

Effects of Vegetable–Fish Co-Culture on CH4 and N2O Emissions from an Aquaculture Pond

Freshwater aquaculture is an important source of greenhouse gas (GHG) emissions. GHG emissions are expected to lead to global warming and climate change. A reduction in GHG emissions is urgently required for the sustainable development of freshwater aquaculture. In this study, a laboratory-scale experiment was conducted to analyze the effects of a vegetable–fish co-culture on CH4 and N2O emissions from a freshwater aquaculture pond. The results show that the co-culturing of yellow catfish with pak choi (PC-F) or water spinach (WS-F) significantly reduced the N2O emission from the aquaculture pond by 60.20% and 67.71%, respectively, as compared with a yellow catfish monoculture (F). However, the co-culture of these two vegetables did not affect the level of CH4 emissions. The reduction in N2O emissions was primarily attributed to the decrease in the concentration of N2O and NO3− in the water. The overall global warming potential (GWP) of CH4 and N2O was significantly reduced by 19.1% with PC-F compared to F, but it did not significantly differ between WS-F and F. PC and WS cultivation improved the food yield by 1555.52% and 419.95% compared to F, respectively. Consequently, the GHG emissions intensity (GHGI) under PC-F and WS-F decreased by 96.15% and 80.77% compared to F, respectively. Altogether, the results highlight that a vegetable–fish co-culture is likely an efficient system for mitigating GWP per unit of food yield in freshwater aquaculture ponds. These results can provide a reference for the mitigation of GHG emissions from freshwater aquaculture.

Strategies in Developing Freshwater Fish Farming to Prevent Stunting

Background: Timor Tengah Selatan is home to some of the most common malnutrition problems in Indonesia. The high rate of stunting in Timor Tengah Selatan is caused by food availability, climate and lack of knowledge about stunting itself. Additionally, the rural nature of the region, its high water demand, poor road infrastructure, and lack of visibility for health workers are significant factors. Therefore, there is a need for efforts to achieve success in fighting stunting, one of which is the strategy of developing freshwater fish farming to overcome stunting in Timor Tengah Selatan. Aim: The research would like to analyze strategies in developing freshwater fish farming to prevent stunting in Timor Tengah Selatan. Method: This research is a type of qualitative descriptive research, while data collection techniques are carried out by exploring journals and other information relevant to the study. Findings: The results of the study show that the strategy for developing freshwater fish farming to overcome stunting in Timor Tengah Selatan is by increasing business and creating additional income for the community as well as encouraging the development of freshwater aquaculture to replace the decline in marine fish during difficult times. It will improve the economy of the region which is also supported by an increase in fishermen's income.

Integrated Multitrophic Aquaculture; Analysing Contributions of Different Biological Compartments to Nutrient Removal in a Duckweed-Based Water Remediation System.

Duckweed (Lemnaceae) can support the development of freshwater aquaculture if used as extractive species in Integrated MultiTrophic Aquaculture (IMTA) systems. These aquatic plants have the advantage of producing protein-rich biomass that has several potential uses. On the contrary, other biological compartments, such as microalgae and bacteria, present in the water and competing with duckweed for light and nutrients cannot be harvested easily from the water. Moreover, as phytoplankton cannot easily be harvested, nutrients are eventually re-released; hence, this compartment does not contribute to the overall water remediation process. In the present study, a mesocosm experiment was designed to quantify the portion of nutrients effectively removed by duckweed in a duckweed-based aquaculture wastewater remediation system. Three tanks were buried next to a pilot-scale IMTA system used for the production of rainbow trout and perch. The tanks received aquaculture effluents from the adjacent system, and 50% of their surface was covered by duckweed. Daily water analyses of samples at the inlet and outlet of the mesocosm allowed quantification of the amount of nutrients removed in total. The portion removed by duckweed was determined by examining the nutrient content in the initial and final biomass. The portion of nutrients removed by other compartments was similarly estimated. The results show that duckweed is responsible for the removal of 31% and 29% of N and P, respectively. Phytoplankton removed 33% and 38% of N and P, respectively, while the biofilm played no major role in nutrient removal. The remainder of the removed nutrients were probably assimilated by bacteria or sedimented. It is speculated that a higher initial duckweed density can limit phytoplankton growth and, therefore, increase the portion of nutrients removed by the duckweed compartment.

Phytoplankton dominates the suspended particulate nitrogen source in the Yangtze River

Globally, the large rivers export amounts of particulate nitrogen (PN) to the ocean, and studying the source and biogeochemical processes of the PN in the large river is important to regional/global N budget and cycle. However, the source apportionments and transformations of the PN along the Yangtze River remain unclear. Here, the elemental and isotopic compositions (N%, δ15N and δ13C value) of suspended particulate N (SPN) and surface sediment N (SSN) were determined in the wet and dry seasons along the Yangtze River, to investigate the seasonal and spatial variation in sources apportionments and transformations of the PN. In the wet season, the δ15N and PN content (%) of SPN increased from the headwater stream (2.3 ± 3.9 ‰ and 0.12 ± 0.04 %, respectively) to the lower stream (6.8 ± 2.4 ‰ and 0.47 ± 0.41 %, respectively) due to the imported anthropogenic N into the downriver section, while there was no significant change in the dry season. There were no distinctly spatial and seasonal variations in the source apportionment of SPN. Phytoplankton was identified as the dominant source of the SPN (42.3–56.9 %), which is probably the result of reducing soil erosion, reservoir construction, rapid urbanization and development of freshwater aquaculture. Terrestrial soil was the major source of SSN (34.5–49.8 %). Furthermore, the significant relationship between the δ15N-SPN values and NO3− concentrations, as well as the lower δ15N-SPN value compared to that of δ15N-NO3−, indicated a strong assimilation process of nitrate during phytoplankton growth. Meanwhile, most of the SSN showed lower C and N concentrations and higher δ13C and δ15N values, compared to those of the SPN samples at the corresponding sampling sites, which might be due to the SSN degradation. Our findings provided valuable information for the N cycle in the Yangtze River and underlined the importance of phytoplankton in the PN inputs.

Freshwater Aquaculture Development in EU and Latin-America: Insight on Production Trends and Resource Endowments

This paper provides a comparative overview of decadal changes in aquaculture production in the European Union (EU-27) and Latin America and the Caribbean (LAC). Contrary to other regions of the world, freshwater fish farming in these two territories is a marginal sub-segment of the aquaculture sector. Using an indicator-based approach, we track development tendencies in freshwater aquaculture, focusing on the main established and emerging species, diversification, and shifts in the mean trophic level of farmed animals. Geographical patterns in production trends are revealed in both regions. The study attempts to explain between-region and between-country differences in aquaculture growth by analyzing freshwater resource endowments at region-level and country-level, using total renewable water resources (TRWR) as an indicator of water-abundancy. Thermal optimum of main produced species is matched against climate conditions prevailing in main producer countries to provide further understanding of spatial heterogeneity in growth rates of aquaculture sector.

Domestication Strategies of Tinfoil Barb Barbonymus schwanenfeldii (Bleeker, 1854): Potential Candidate for Freshwater Aquaculture Development

This paper discussed domestication strategies of Tinfoil barb from different populations for evaluation of potential fish candidate for freshwater aquaculture development. Collection and maintenance of wild-caught adult fish was the first step in domestication strategies followed by characterization of fish, broodstocks selection and maturation, control of fish reproduction, and larval rearing. The Tinfoil barb presented an excellent performance to adapt to the new environment. This was indicated by survival rate of the fish acclimated in the captive environment of about 69.28 ± 19.64% for five weeks. Phenotypic characterization revealed that Tinfoil barb collected from Borneo, Java, and Sumatra have different morphological characters. Based on genetic characters, polymorphism percentage and heterozygosity of the Borneo tinfoil barb population provided the highest performance followed by Java and Sumatra. The growth model of all Tinfoil barb populations was allometric negative indicating a faster increase in length than in weight. Reproductive performance presented that the fecundity of Tinfoil barb female from Borneo was the highest (2795-5099 eggs/gram) followed by Sumatra (1822-2976 eggs/gram) and Java (2210 eggs/gram). The artificial reproduction performance of broodstock from Borneo also presented more excellent performance than other population after hormonal treatment. Fertility rate and hatching rate were 94,33+0,29 % and 77,44+1,03%, respectively. Java Tinfoil barb had fertility rate 93+0,05% and hatching rate 73,67+3,15%, while it was no fertility rate and hatching rate obtained from Sumatra brood-stock group. Wild-caught adult Tinfoil barb from Borneo population presented the best performance used for potential brood-stock regarding genetic characters, reproductive performances, and response to artificial reproduction. Future studies need to be concerned with the acceleration of gonad maturation and the improvement of larval rearing technology for improvement of domestication strategies of Tinfoil barb as a potential candidate for freshwater aquaculture development.

The total factor productivity index of freshwater aquaculture in China: based on regional heterogeneity.

Continuously improving freshwater aquaculture efficiency will promote the sustainable development of freshwater aquaculture, which is crucial to ensure aquatic food supply. In particular, measuring the total factor productivity (TFP) of freshwater aquaculture to find ways to improve its efficiency is of great significance to sustainable development of freshwater aquaculture industry. Therefore, based on directional distance function, this paper constructs a meta-frontier Malmquist index (MMI) model by considering the regional heterogeneity to evaluate the TFP of freshwater aquaculture of China from 2004 to 2019. The results show that (1) from the perspective of time, TFP fluctuated significantly from 2004 to 2012, while after 2013, TFP remained around 1 with small fluctuation. In other words, freshwater aquaculture in China began to maintain a relatively negative state of development. (2) From a regional point of view, this study found that freshwater aquaculture TFP of inland region is better than the TFP of coastal region. (3) From the decomposition index, the variation of freshwater aquaculture TFP was driven by the combined effect of technology change (TC) and technical efficiency change (EC). In addition, the decomposition index efficiency shows that the technical efficiency decreases and the management efficiency changes little. (4) The gap of freshwater aquaculture technology in coastal areas is very small, and close to the optimal technical level. While in inland region, on the contrary, there is more room for improvement. According to the above empirical results, this paper finally gives some policy suggestions to improve the TFP to ensure the sustainable development of freshwater aquaculture.

Parasitic copepods Caligus lacustris (Copepoda: Caligidae) on the rainbow trout Oncorhynchus mykiss in cage aquaculture: morphology, population demography, and first insights into phylogenetic relationships.

Herein, data on rainbow trout infections with the copepod Caligus lacustris in cage aquaculture on Lake Ladoga is presented. Caligus lacustris (n = 127 ex.) were collected from a farm in Lake Ladoga housing cage-reared rainbow trout to describe the size-age and sex structure of the copepod population. Morphological features of the copepods were evaluated according to 10 characters with terminology proposed by Kabata and Gusev (J Linn Soc (Zool) 46(309):155-207, 1966). To determine the phylogenetic position of C. lacustris within the genus Caligus, fragments of the cytochrome c oxidase subunit 1 mitochondrial gene (COI, 645bp) and 18S rRNA gene (1617bp) were sequenced. An increase of parasite prevalence was observed as the lake was warming up from July to September. The morphological features of the crustacean's larval and adult stages, characterized by specific parameters of quantitative traits, are described. Three COI haplotypes and only one 18S rRNA haplotype of C. lacustris were identified among five samples. Based on 18S rRNA analysis (resolution of the COI tree was poor), we can conclude that the clade containing C. lacustris, and the aforementioned sister species, appears as an early radiation of the genus Caligus. The development of freshwater aquaculture contributes to the transfer of the native parasite C. lacustris to farmed rainbow trout.

In vitro follicle culture shows that progestagens are the maturation-inducing hormones (MIH) and possible regulators of the ovulation-mediating hormone PGE2 in female Eurasian perch Perca fluviatilis.

In European aquaculture, Eurasian perch, Perca fluviatilis L., is perceived as one of the most highly valuable freshwater fish species and a strong candidate for the development of freshwater aquaculture. In the pursuit of improving the quality of reproduction in this domesticated species, investigating the hormones mediating the final oocyte maturation (FOM) is therefore indispensable. But, the exact nature of the maturation-inducing hormone (MIH) in Eurasian perch is unknown. To further validate the existence of a maturation-inducing activity behind potential hormonal candidates in this species, we in vitro tested a group of nine hormones: cortisol (Co), 11-deoxycortisol (11-D), corticosterone (coS), 11-deoxycorticosterone (DOC), 17α,20βdihydroxy-4-pregnen-3-one (DHP) and 17α,20β,21 trihydroxy-4-pregnen-3-one (THP), prostaglandin E2 (PGE2), estradiol-17β (E2) and testosterone (T), in their ability to trigger FOM advancement and the production of sex steroids potentially involved in FOM. Using mature female perch, two in vitro experiments were conducted with oocytes at the start of the FOM. The follicles were incubated for 62 h in Cortland media with and without human chorionic gonadotropin (hCG). By the end of the incubation, only DHP and THP triggered the full advancement in FOM even at low doses with the effect of DHP being in vivo validated. However, the de novo productions of E2 and DHP were not shown to be regulated by either of the MIH candidates. Progestagens are hence more credible candidates as MIH than corticosteroids in Eurasian perch. Our in vitro study also revealed that both PGE2 and DHP are strongly associated with ovulation and that PGE2 might have slightly contributed to such DHP activity.

Financial Feasibility Analysis of Gourami Farming in A Collaborated Business Association System

As catch fisheries have experienced overfishing symptoms, which resulted in a decrease in fish resources, the government must develop freshwater aquaculture. Sleman Regency has known for its growing freshwater aquaculture development, which supplies about 70% of the total fish production in Yogyakarta Special Province. Despite the rising demand for fish consumption, fish cultivators face problems in the capital, infrastructure, weak bargaining power, quality problems, and long distribution chains. One way to overcome these problems is to strengthen the bargaining position through the fish farmer groups. This study aims to analyze the financial feasibility of gourami farming, whose owners are members of business associations. In the business association, fish farmers agree to collaborate in running their business to cultivate gourami in a supply chain process ranging from production to marketing. The collaboration of fish farmers integrates four segments of the fish-raising chain system, consist of seedling handling from 0 to1.5 months old, raising fish from 1.5-to 3.5 months, from 3.5 to 6.5 months, and 6.5 to 12 months. Using a quantitative research method, this study analyzes 40 fish farmers in Seyegan, Sleman District of Yogyakarta. The financial feasibility analysis uses the net present value, benefit-cost ratio, internal rate of return, and break-even point. Results of these analyzes indicate that financially, the collaborative gourami farming in Seyegan District is feasible with an NPV of segment I is Rp 11,122,952.00, of segment II, is Rp 2,174,940.00, of segment III, is Rp 9,748,705.00. Of the segment, IV is Rp 18,691,435,86. The B/C Ratio for segment I is 1.87, segment II is 1.55, segment III is 2.13, and segment IV 2.05. The BEP value for segment I is Rp 1,709,228.00, for segment II is Rp 1,779,290.00, for segment III is Rp 852,100.00, and for segment IV is Rp 2,000,672.00.

The role of women in freshwater aquaculture development in Kenya

Abstract For many years, aquaculture has been erroneously viewed as a male-dominated sector, offering women inadequate opportunities partly due to the high capital investment requirement and or the technologies linked to the venture. Women work in all areas of the aquaculture value chain but their opportunities have not kept pace with aquaculture growth. Hence, they form a larger component of the poor, limiting their income-generating activities and asset building potential. Gender disaggregated statistics that could track women’s engagement in aquaculture activities in Kenya are scanty. Hence, women’s presence, influence and interests are invisible. All aquaculture labour practices should embrace the Sustainable Development Goals 5 that focus on gender equality and empowerment of all women and girls. To that end, gender equality must be mainstreamed into aquaculture planning, development, monitoring and evaluation. This will require concerted political efforts by sector leaders, advocates and gender champions, supported by new technical instruments for implementation. The study leverages on incorporating gender lens and making gender visible in every phenomenon, questioning if, how and why processes, opportunities and standards differ systematically for women and men and not solely for women. Finally, it proposes sections where women’s engagements can be strengthened to increase the importance of aquaculture production in Kenya.

Mycological and histopathological identification of potential fish pathogens in Nile tilapia

Due to recent rapid progress in the development of freshwater aquaculture in Egypt, many new and precedent fish fungal diseases have emerged. Nile tilapia (Oreochromis niloticus) has been threatened by various diseases that have harmful health consequences and prone to mortalities. The current study was conducted (using 800 randomly collected diseased cultured and wild Nile tilapia) to identify the three most serious fungal pathogens that induced mortalities. The infection can be superficial as Saprolegnia spp. that is characterized by focal dermal cottony growth and is the most common in occurrence. While, systemic infection as Ichthyophonus sp. that invades the highly vascularized organs impairing their functions, Branchiomycosis is a devastating disease that affects gills obstructing blood flow. Saprolegnia spp. was identified through the morphological characters of culture on Sabouraud's dextrose agar media (SDA) and histopathological examination of tissue. Surprisingly, Saprolegnia spp. grew on Eagle's Minimum Essential Medium (MEM) at pH 7.0 only giving zoospores. Ichthyophonus sp. was isolated and is characterized by spherical double-walled multinucleate schizonts that are verified in squash preparations from infected internal organs (liver, spleen, and kidneys) and tissue sections. Additionally, it developed two different forms of growth on MEM depending on culture medium pH. Branchiomyces spp. exhibited different stages of growth in gills and so appeared congested, paled, white-colored or marbled according to the progress of infection. A key diagnostic feature to genus Branchiomyces is the branching of hyphae at their tips with the first report for a description of such branching in compression techniques from gills. Also a microscopic examination of fungal culture aids in the identification. Herein, we report Branchiomyces sanguinis for the first time and Branchiomyces demigrans in Nile tilapia in Egypt. Both species are distinguished based on the shape and diameter of hyphae in compression techniques from infected gills as well as the diameter and location of spores in histological sections. Koch's Postulate confirmed the identity of the investigated pathogens. The current research represents the first comparative mycological and histopathological study for Saprolegnia spp., Ichthyophonus sp., and Branchiomyces spp. as well as their prevalence in wild and cultured Nile tilapia throughout the different seasons in Egypt.

Экструдированные стартовые комбикорма для клариевого сома

Industrial fish-breeding is a promising trend for freshwater aquaculture development. The production of clarid catfish in Kazakhstan has advantages over traditionally grown fish species (trout, sturgeon) due to their valuable edible qualities. Clarid catfish grows very quickly even at high seeding densities, is undemanding to the environment, resistant to diseases, and effectively assimilates food. When growing clarid catfish in water recycling systems it is possible to refuse using oxygen equipment, because the fish species can use atmospheric air for breathing. As a result, the construction of such plants can save up to 40% of capital investments. In the course of the research, the physiological nutritional requirements of clarid catfish juveniles were established. Based on the data obtained there have been developed two extruded starter compound feed recipes for clarid catfish juveniles containing protein/fat 53.5 : 11.4 and 61.85 : 5.82 and energy exchange energy value varying within 16.46 - 17.12 MJ/kg. There have been conducted the production tests on assessing the efficiency of the developed compound feed and their intake by larvae and clarid catfish fry in the fish farms of “Kapshagayskoye NVH-1973”, LLP and “HalykBalyk”, LLP. The feed Aller Agua (Denmark) served as a control feed for comparing the nutritional and consumer qualities of the developed feed for trout. The determined feeding ratio of the developed feed did not exceed 0.93 units, it was insignificantly inferior to the import feed. The fry survival rate made 76% when using both the control and developed feed. The compound feeds for clarid catfish juveniles were developed by extruding, which allowed to obtain increased digestibility, water resistance and extended storage life. Introducing these feeds into the fish breeding practice will help to increase the efficiency of clarid catfish fry growth and expand opportunities of aquaculture facilities.

Growth monitoring of koi fish (Cypri nus carpio) in natural hatchery techniques in Umbulan, Pasuruan, East Java

Koi fish (Cyprinus carpio) are one of the most popular ornamental fish commodities in the world. The purpose of this study was to analyze the growth and monitoring of koi fish on natural hatchery techniques. This research was conducted at the Technical Implementation Unit of Freshwater Aquaculture Development in Umbulan, Pasuruan, East Java Province between December 2017 and January 2018. The koi fish breeding technique in Umbulan is done naturally using two females with the same weight of 1.5 kg and three males with a weight of 1.8 kg, 1.5 kg and 1.5 kg respectively. The maintenance of the larvae included feeding, the monitoring of the larvae and the associated water quality measurements. The hatching rate of the koi fish eggs was 80%. The specific growth rate during maintenance was 0.164%, and the growth rate for every week was 1.822 x 10−3 g/day; 1.34 x 10−3 g/day; and 1.75 x 10−3g/day. The feed conversion ratio was 1.38 and the survival rate was 73.8%. The average of the water quality values including temperature was 26.25° C. The pH was 7.53, the dissolved oxygen was 6.26 mg / L, NO3 was 0.75 mg / L, NO2 was 0.01 mg / L, Fe was 0.06 mg / L and PO4 was 0.74 mg / L.

RIVER DAM EFFECTS ON CUBAN FISHERIES AND AQUACULTURE DEVELOPMENT WITH RECOMMENDATIONS FOR MITIGATION

Dam construction in Cuba and their use for freshwater aquaculture development are explained. Some of the environmental impacts of Cuban freshwater reservoirs, particularly in fisheries, the salinization of coastal lands, and effects on marine fisheries, are reviewed and analyzed. Some argumentation and explanations given are in response to remarks on the impact of Cuban dams on species composition of reservoir fishery landings and on coastal marine fisheries. The main impacts of dams are on estuarine and adjacent coastal lagoons. The reduction (85%) of freshwater flow over coastal lagoons had increase salinity in more than 15 , temperature (about 4-5 C), sedimentation (50-60%), and has decreased nutrient inputs. However, the nutrient concentrations of coastal waters are still at the mesotrophic level and the influence of underground water and increased urban and industrial effluents to more than 160,000 tons/year are suggested as possible additional nutrient sources. The main impact of dams on coastal waters are on coastal lagoons and river deltas, with negative consequences for the fishery of several euryhaline species, although is not the principal cause of the decrease of marine fishery landings. River dams have also accelerated the natural ageing process of coastal lagoons, especially because their sediments are not removed in the absence of river floods. Several practical actions are recommended to mitigate the negative effects of dams and to increase fish production in freshwater reservoirs and coastal lagoons. A polyculture program is recommended, based on the integrated Vallicoltura system principles to rehabilitate coastal lagoons, including the use of mechanization to remove bottom sediments.

TRANSFERÊNCIA DE TECNOLOGIA EM PISCICULTURA DE ÁGUA DOCE: A EXPERIÊNCIA DO PROJETO “PEIXE MAIS” NO ESTADO DO TOCANTINS

Aiming to promote the development of freshwater aquaculture in Tocantins, Embrapa Fisheries and Aquaculture, in partnership with the Ministry of Fisheries and Aquaculture, developed the Project called “Peixe Mais” (which refers to more technology in freshwater chain), which uses the technology transference as rural development tool, interacting and promoting strategic changes in the production chain of freshwater fish. One of the actions of this project to be reported in this work is the experience of Continuing Training in Freshwater Fish Farming, which was held in 2014 in the city of Araguaína, State of Tocantins, Brazil, with focus on native fish farming technology transference through technological update of multipliers. In this context, the goal of this paper is to present the experience of "continuing training in freshwater fish farming" in the Project in regard to methodological aspects and results transferred to rural multipliers of Tocantins. Among the results, it was noted that the initiative aimed to bring different realities in this territory, promoting a discussion, creating communication between research activities and the rural extension, and transferring technology and knowledge that underlie the links in the fish production chain for field workers who will multiply the knowledge acquired.

WATER LEVEL VARIATIONS FOR EGG HATCHABILITY AND LARVAL SURVIVAL OF KELABAU FISH (Osteochilus melanopleura Blkr)

The purposes of this study were to observe and analyze the water level variations of the culture media that were optimal for egg hatchability and larval survival of kelabau fish kept in aquarium. This study was conducted in the Freshwater Aquaculture Development Centre (FADC) Banjar Regency in August 2015. The method used in this study was experimental, using a completely randomized design with 3 treatments (A = water level of 15 cm/aquarium), (B = water level of 25 cm/aquarium), (C = water level of 35 cm/aquarium) and 3 replications. The parameters measured in this study were the egg hatchability, survival rate, relative growth rate, and water quality (temperature, pH, DO, Ammonia). Data were analyzed by Anova and the differences between treatments were tested with Duncan test. The results showed that the water level very significantly affected the egg hatchability with the highest value in B (38.29%) followed by C (31.83%) and A (14.04%). The highest survival rate was in C (79.73%) followed by B (65.10%) and A (21.83%). The relative growth rate had not significant effect with the average results between all treatments (104.92 – 117.27%). The water quality of the culture media was still good to support the growth and survival of fish.

SISTEM INFORMASI GEOGRAFIS BUDIDAYA IKAN LELE

Kampar is a regency in Riau Province that has a very large potential for freshwater fisheries. Kampar Regency has a strategic geographical location, bordering Pekanbaru and Siak Regency in the north and Kuantan Singingi Regency in the south, and bordering Rokan Hulu Regency and West Sumatra province in the west, while in the east it borders Pelalawan Regency . With its geographical location Kampar has the potential for the development of freshwater aquaculture, especially aquaculture ponds (fish cages) and floating nets. Seeing the information of fish cages in Kampar Regency, which are still known from the mouth of the mouth and not yet published, the Fisheries Service needs to provide information about the locations of fish cages in Kampar Regency. In making it easier for the Fisheries Service to provide information about the location of fish cage locations in Kampar District, the authors are interested in making the title of a web-based Geographic Information System for fish cages. The development system used in this study is to use the waterfall method. The map design displayed by this system uses google maps.